Another Kick in the Pants for Kinesio Tape

For those who don’t know, Kinesio Tape is the colorful, stretchy tape that you see displayed on many athletes. The purported benefits are numerous, with each one being more imaginative than the former.

kinesiotape  Last year, I wrote a piece that outlined the data on Kinesio Tape and looked at a couple meta-analysis papers (studies that pool the data from all the other studies). These meta-analysis studies not only show a lack of data supporting Kinesio Tape, but actually provide evidence that Kinesio Tape is no better than sham/placebo.
That was last year.

More recently, in June 2014, the Journal of Physiotherapy published another review of the available data and came to the same conclusion.

Looking at studies on shoulder pain, neck pain, low back pain, knee pain, plantar fasciitis and other complaints, the authors concluded, “The current evidence does not support the use of this intervention in these clinical populations“. In other words, there the evidence does not support the idea of using Kinesio Tape for any of these complaints.

Unfortunately, many therapists will not only ignore this evidence, but continue to use it on patients and bill insurance companies for it. It is possible that billing insurance companies for the time spent with the patient could be considered fraudulent, as I wrote about here.

Polarized Training and Injury Prevention

Training methods for a triathlon or longer running events have traditionally been a bit of an enigma for many athletes and coaches. There have been so many methods touted (Lydiard, Daniels, Run Less/Run Faster, Crossfit’s Endurance etc) how is the average runner supposed to know what to do?

In this post, I will talk about the method I typically endorse – the “Polarized Training” method – a training method that leans heavily on low heart rate/Zone 1 training, with some high intensity workouts/Zone 3 training but very little Zone 2/race pace training. This flies in the face of the “specificity of training” notion, but I base this recommendation on all the research outlined in this blog post.

If you’re short on time, let me give you this brief outline: Injuries in distance running are extremely common and I blame training errors for most of them. The “no pain, no gain” attitude is all to common and is unfortunately promoted by many coaches. Despite the lack of “specificity of training”, polarized training is the method that I typically endorse. I base this on many hours of researching papers and looking at what world-class endurance athletes are apparently doing and studies that compare polarized training to other methods of training.

I am assuming that there will be a varying amount of knowledge in the people who read this article, so I have divided it up into sections. In Section #1, I will get angry email replies from coaches. Section #2 briefly outlines some of the basic terms of exercise physiology needed to understand the rest of the article. In Section #3, I talk about why there should be an emphasis on Zone 1 training. Section #4 explains what polarized training is and Section #5 outlines some studies showing that for endurance athletes, polarized training generally seems to be a superior way of training. You can click on the links below to be taken to each section.

Section 1: My thoughts on coaching runners/triathletes

Section 2: A very brief primer on exercise physiology terms

Section 3: The case for Zone 1 training in endurance athletes

Section 4: What is Polarized Training?

Section 5: The evidence behind polarized training.

Section 1: My Thoughts on Coaching

Let me start by saying that I’m not a running coach. What I am about to say is not to throw all coaches under the bus…just some coaches.

Despite having taken multiple courses in exercise physiology in undergrad and chiro school as well as doing some brief work in a lab testing athletes in VO2max, lactate threshold etc., I don’t feel capable of coaching athletes because I don’t feel knowledgeable enough…plus I don’t have the patience for most athletes! That being said, I think it’s important that most runners/triathletes DO ask their running/triathlon coaches what educational background they have. A working knowledge of how to use the TrainingPeaks website doesn’t qualify.

I have seen way too many coaches have the “no pain, no gain” philosophy. Their runners do tempo run after tempo run and suffer the consequences in injuries, overreaching and burn-out I see this happening in well intentioned community level tri/running coaches, high school coaches, but particularly in collegiate coaches. Don’t even get me started on the running coaches who claim to do running gait analysis – that actually keeps me up at night!

So, since I’m not a coach, you may be wondering why I want to talk about endurance training. The answer is simple – the majority of running injuries are due to training errors – too much (volume), too soon (frequency), too fast (pace).

If you have terrible running mechanics, your body’s tissues should be able to adapt; given enough time. Loading the body’s tendons, ligaments, muscles and bones in the “zone of optimal stress” will allow them to become stronger, more resilient and resistant to injury. The “zone of optimal stress” is kind of a Goldilocks idea: Not enough stress applied to the tissues means the tissues won’t be exposed to enough stress to stimulate an adaptation response. Too much stress means the amount of stress exceeds the physical capabilities of the tissues and they will fail (injury). Just the right amount of stress means that the load is enough to stimulate adaptation, but not enough to cause failure.

Finding the zone of optimal stress for each athlete as an individual, is the art of being a running coach.

I find that many of my patients have undergone some amount of training errors. For example, more than 50% of their weekly mileage is on one long run, they exhibit a couch to marathon in 1 year type of mentality etc., but the overwhelming amount of training errors are that they just try and run too fast, too often. They do way too many tempo runs and way too many training sessions at or near race pace. This is where we get into the convergence of the coaching and the clinician: if the coach and the clinician have different goals and are giving different advice, the athlete is stuck between two competing interests.

That being said, I often run into endurance athletes and coaches who are resistant to the idea of training below their aerobic threshold. They can’t understand how not running at race pace will help them in a race (the lack of specificity of training). I have written about this in the past but this post is an update where I want to present more up to date studies.

Section 2: A Brief Primer on Exercise Physiology Terms:

Before we get into the nuts and bolts of polarized training, let me do an extremely brief primer on some exercise physiology terms.

Aerobic exercise: Low intensity exercise where oxygen is used by the body in the steps needed to generate energy

Anaerobic exercise: Higher intensity exercise that is intense enough to produce lactate as a bi-product of energy production. Uses two sources for energy production: 1) Creatine Phosphate and ATP and 2) Anaerobic gycolosis which uses glucose

Ventilatory threshold 1 (VT1): While exercising, your breathing is relaxed enough that you can speak in full sentences. Any increase in exercise intensity will cause a spike in your breathing rate.

Ventilatory threshold 2 (VT2): While exercising, your breathing allows you to speak, but not in full sentences. Any increase in exercise intensity will increase the lactate concentration in your blood to rise beyond a point where sustainable exercise is possible.

The American Council on Exercise has a great video explaining it all here:
ACE video VT1 and VT2

So now that we know the basics of threshold training, we can start talking about zone training. Depending on where you are from, or who is talking, there are either 3 or 5 zones and they have to do with the VT1 and VT2. These charts should explain:

5 zone intensity model for training
From Polarized Training, by Frankie Tan
http://www.triathlon.org.nz/Polarized%20Training%20by%20Frankie%20Tan.pdf

5 zone model on left, 3 zone model on right

In the 3 zone model, it is generally accepted that any exercise in Zone 1 is below VT1 and any exercise in zone 3 is above VT2:

3 zone intensity model
From Polarized Training, by Frankie Tan
http://www.triathlon.org.nz /Polarized%20Training%20by%20Frankie%20Tan.pdf

These zones are basically related to blood lactate levels, which is a bi-product of energy production. In Zone 1, blood lactate is very low. In Zone 2, lactate production is high, but an equilibrium can be achieved through increased respiration rate. In Zone 3, lactate production exceeds the body’s ability to clear it and fatigue is imminent.

The inevitable question now, is, “How do I know what my running pace should be to train in zone 1, 2 or 3?” This is a legitimate question and we can get very complicated in its answer. There are many services available to runners where VO2max testing is available. The drawback here is there is a significant fee associated with it, and the runner’s VO2 max will hopefully change as you train, so the runner will be required to revisit the facility periodically in order to be re-tested. Another method has been proposed by Phil Maffetone which is a relatively simple method to estimate your VT1 and can be found here. In his method, the runner simply subtracts his age from 180 and then adds or subtracts based on some factors such as running history and previous injuries, illness etc.

I recommend an even simpler, but more effective method (in my opinion) and one that can be performed every time you run. This method is simply to pay attention to your breathing. We know that when a runner’s pace exceeds VT1, there is a spike in his breathing. In addition, there is a distinct difference in breathing after the runner exceeds VT2. If the runner simply pays attention to his/her breathing, they should be able to distinguish when they have passed each threshold. Breathing and pace do not have a linear relationship and one can see from the graph below. The breathing rate curve takes distinct changes in it’s slope as the runner passes VT1 and VT2:

From American Council on Exercise http://www.acefitness.org/certifiednewsarticle/709/ace-ift-model-for-cardiorespiratory-training/
From American Council on Exercise
http://www.acefitness.org/certifiednewsarticle/709/ace-ift-model-for-cardiorespiratory-training/

There is benefit to “going by feel” with this method since our physiology changes every day. If we have our VO2 max tested, or go by our % of max heart rate or the Maffetone method, we are going by a number on a heart rate monitor, but the VT1 and VT2 relative to our heart rate can change daily, depending on our physiology for that day. Most runners know they have good days and bad days, so we should monitor our breathing/pacing daily to determine our zones on any given day.

Section #3: The Case for Zone 1 Training.

While the main thrust of this article is on polarized training, I feel it necessary to talk about the importance of Zone 1 training since polarized training requires athletes to spend 75-85% of their training time in Zone 1. It is Zone 1 training that most amateur endurance athletes are resistant to when I bring it up in my clinic; “How can you expect me to run fast in a race if most of my training is at a slower pace?“. I get called a nutter, or worse.

There are three main arguments for Zone 1 training for endurance athletes; reducing injury, increasing performance and reducing over-training.

a) Reducing Injury: This should be intuitive, but some aspects of increased pace are different. A good review of the literature by Nielson et al (here) found that PFPS, ITBS, patellar tendinopathy and other injuries may not be related to pace, but injuries such as achilles, plantar fasciopathy and calf strains are related to pace. In addition, hamstring injuries appear to be more prevalent with increased pace. In a separate study, Nielson (here) found that the vertical ground reaction force at initial contact to increase by 100% during an increase in speed from 2 m/s to 6 m/s, while the increase in the anterior-posterior force during the propulsive phase at a similar increase in speed was 250%.

Again, it would seem intuitive that injury rates increase as pace increases, given the higher muscle loads, ground reaction forces and propulsive forces.

b) Increasing Performance: Craig Neal PhD, posted his thesis online which is extremely in-depth, but worth the read if you are a coach. In his thesis, he analyzed many papers on the training distribution of elite-standard athletes and he stated that most training time spent in zone 1 was >80% of the total training time. In contrast, studies on sub-elite runners show less time spent in zone one (71%). One study showed negative correlation between time spent in zone 1 and performance time during a 10 km cross country race (i.e. more time training in Zone 1 was resulted in faster race times).

“Thus, data to date suggest that more time spent training in zone 1 is beneficial for physiological adaptation and subsequent exercise performance. Studies with elite-standard athletes (Ingham et al., 2008) and sub-elite athletes (Esteve-Lanao et al., 2007) that have examined training-intensity distribution agree that a greater percentage of training time spent in zone 1 is beneficial to performance and/or physiological adaptation. These studies found that with no difference in training load, a group focusing on training in zone one (≥80%) had a greater improvement in performance(Esteve-Lanao et al., 2007) and gained greater physiological adaptation (Ingham et al., 2008) than a group who spent less training time in that zone (~70%)”

c) Reducing over-training/over-reaching: Over-training/over-reaching can be measured by a number of variables including Heart Rate Variability, immunological parameters, metabolic markers in the blood (on a personal note, my TSH jumped to 46 following an Ironman race when I was out of shape), hormone levels, reduced performance etc. Billat et al here) found that blood markers for over-training/over-reaching are increased if high intensity training is performed >3X/week in runners. Furthermore, Seiler et al (here) found that VT1 is the cutoff point for disturbances in the autonomic nervous system (an imbalance in the nervous system is what is disturbed in over-training/over-reaching). For a thorough discussion of over-training vs overreaching and the physiologic consequences, I highly recommend Halson and Jeukendrup’s paper, “Does Over-training Exist?” (full text here)

Section #4: What is Polarized Training?

Now that we’ve established a basic understanding of Zones and VT1, VT2, we can move on to how to properly utilize that knowledge for endurance training.

There are two popular training methods when it comes to zone based training: Threshold Training and Polarized Training. Threshold training does the majority of training at or near race pace (Zone 2). Conversely, polarized training states the vast majority of training should be done in Zone 1 (approx 75-85%) and some in Zone 3 (15-20%), but very little in Zone 2 (<10%). Essentially, the polarized method gets it’s name due to polarizing the training away from the middle zone 2 and into either Zone 1 or Zone 3 (much more in Zone 1)

From Seiler et al. http://www.ncbi.nlm.nih.gov/pubmed/16430681
From Seiler et al.
http://www.ncbi.nlm.nih.gov/pubmed/16430681

The threshold model has been studied many times and shown to have significant improvements in untrained subjects (here, here and here). Similarly, the polarized training method has been studied numerous times, as I will outline in Section 3 below. It is my opinion, based on studies comparing the two, that the polarized method is much better than threshold training. The philosophy of polarized training comes from Stephen Seiler PhD and the late Charlie Francis (a Canadian sprint coach ahead of his time). Essentially, Zone 2 training is considered a “black hole” since it is poor at achieving the benefits that Zone 1 and Zone 3 training are capable of:

From: http://complementarytraining.blogspot.com/2014/01/training-periodization-sprinting-tempo.html
From: http://complementarytraining.blogspot.com/2014/01/training-periodization-sprinting-tempo.html

Why not do all training at low intensity? As outlined in the chart above, both high and low intensity training have their benefits and to focus on one would be folly. It is evident that most elite athletes do around 75-85% of their training in Zone 1, however doing all training in Zone 1 would not promote other changes in the neuromuscular system and cardiovascular system such as increased Vo2 max, lactate threshold and economy. As such, it has been shown that adding a small amount of high intensity training over a 4-8 week period can improve performance significantly in well trained endurance athletes (here, here and here)

Why not do more training at higher intensity? Adding more intensity does not seem to advance performance, but can induce over-training/overreaching (here) . The question is – how much high intensity is too much? That certainly is an individual question, but it is without question that overreaching can be easily induced with increasing intensity. As I wrote above, Billat et al., found that high intensity training 3X/week is enough to cause over-reaching/over-training. A thorough review of the literature has been done by Halson and Jeukendrup in their paper, “Does Over-training Exist?” (full text here)

Section #5: The Evidence Behind Polarized Training

This section will look at the evidence and will be subdivided into 2 categories: i) how do the top athletes train (i.e. observational studies) and ii) Studies comparing threshold and polarized training (i.e. intervention studies)

i) How do the world-class endurance athletes train?

Let’s first look at the training logs of world-class athletes to see how they actually train. Most people are surprised by how little race pace training elite endurance athletes actually do. This lack of specificity training seems counter intuitive to most, but take a look at these studies looking at training logs:

a) Billat et al (full text here): This 2001 study looked at the training logs of elite marathoners (2:06-2:11 marathon times). This is the distribution of their training intensities:

Specificity-of-Training is lacking in the training plan for elite marathoners
Specificity-of-Training is lacking in the training plan for elite marathoners

b) Karp (full text here): This study looked at training logs for 93 U.S. qualifiers (37 men, 56 women) for the 2004 Olympic Marathon Trials. The vast majority of training distance was slower than marathon pace. The author states, “The tendency to perform most training at a low intensity is a common finding of studies on elite endurance athletes…men averaged only 9.7% and women 12.8% of their yearly training at marathon pace”

c) Seiler (full text here): This study looked at 12 elite, national team level cross country skiers and followed then for 318 training sessions. They found the training intensity distribution as follows:

From Seiler 2006 – http://www.ncbi.nlm.nih.gov/pubmed/16430681

d) Orie et al, 2014 examined the training logs and interviewed coaches and athletes from 38 years of speed skating. These were national level skaters that went to many Olympics and collected 8 gold, 5 silver and 4 bronze Olympic medals. They saw a major shift in training toward a polarized method and concluded: “Our data indicate that for successful middle- and long-distance speed skaters there was a shift toward polarized training over the last 38 years. Surprisingly, there was no increase in net training hours and hours of on-ice skating over these years, while performance increased considerably.

Orie et al 2014 training distribution for speed skaters

e) Fiskerstrand et al (full text here): This paper looked at 27 Norwegian rowers from 1970-2001. Together, these athletes won 11 gold, 15 silver, and 8 bronze medals with a distribution seen at the senior European (three medals), World (23 medals), or Olympic (eight medals) levels. Over the 30 year time span, the best athletes got better. Compared with the winning athletes in the 1970’s the athletes in the 1990’s increased their VO2 max by 12% on average.

After looking at their training logs, the researchers found 3 main changes in training: 1) an ~20% increase in training volume, 2) a significant shift to emphasize training at an intensity below VT1 (<2mmol lactate) and 3) a significant increase in altitude training. With these three variables at play, it is difficult to single out increases in Zone 1 training as the main factor for success. However, I think we can de-emphasize altitude training due to many recent studies showing that the promise of altitude training may not be what we once thought it was (here and here). Alex Hutchinson made an interesting post about that here.

Regardless of the reason why these improvements in Vo2 max were seen, the fact remains that there has been a historical shift toward increased volume of training below VT1. As the authors of this last study concluded, “Large increases in basic endurance training at intensities clearly below the first lactate turn point have been utilized.”

From Fiskerstrand et al -Training and performance characteristics among Norwegian international rowers 1970-2001.
From Fiskerstrand et al -Training and performance characteristics among Norwegian international rowers 1970-2001.

ii) Studies Comparing Threshold and Polarized Training

When looking at the way elite endurance athletes train, one has to wonder whether or not they train 75-85% of the time in Zone 1 because it’s the best way to train, or because that’s “just the way it’s done”. These next studies actually compared polarized training to other forms of training to see what happens when training intensity distribution is altered:

a) Esteve-Lanao et al., 2007 took 12 sub-elite runners (10km PR’s of 30 -35 mins) and split them into 2 groups for a 5 month period. Group 1 was to run with in Zones 1,2 & 3 for 81%,12% and 8% respectively, while Group 2 was to run in Zones 1,2 &3 for 67%,25% and 8%. Their weekly running volume was equal between groups.

exercise intensity distribution for Esteve paper
exercise intensity distribution for Esteve paper

Following the 5 month training in these zones, Group 1 (the polarized group) improved significantly more than Group 2.

Results from Esteve paper_edited-1

b) Neal et al., 2013 published a study specifically on polarized training. They had 12 cyclists take 4 weeks off to slightly detrain, then they did either a polarized training block (80% zone 1, 0% zone 2, 20% zone 3) for 6 weeks or a threshold training block (57% zone 1, 43% zone 2, 0% zone 3) for 6 weeks. Following this, they did another 4 week detraining period and then switched training methods (the athletes that initially did polarized, switched to threshold and the athletes that initially did threshold, went to polarized). Despite the lower training load (intensity X duration) during the polarized training block, the athletes ended up having better improvements in performance (peak power output and high-intensity exercise capacity) following the polarized training block than the threshold block.

This study is a really well designed and convincing study. I find it intriguing that the polarized group did NO training in Zone 2. Alex Hutchinson spoke about this study in this article and posted this chart of the results:

Neal results for polarized training 2014
Neal results for polarized training 2014

c) Yu et al 2012, had 5 men and 4 women from the Chinese National speed skating team undergo a threshold training (40% Zone 1, 56% Zone 2 and 4% zone 3) in 2004-5 and then switch to a polarized training model (82% Zone 1, 5% Zone 2 and 13% zone 3) in 2005-6. They found that under the polarized training model, all skater’s performance improved and their lactate after competition decreased significantly. The interesting aspect of this study is that it was done on sprint skaters, not endurance. There are certainly many holes in the design of this study, so it’s wise to be a bit skeptical of these results.

Skaters went to polarized model for training in 2005-6
Skaters went to polarized model for training in 2005-6

Conclusion: Polarized training appears to be a common training method for most world-class endurance athletes and is backed up by interventional studies comparing it to other forms of training. It is worth noting that this method will not work for all people, but it is a good place to start.

Footnote: A great deal of this update is also reviewed in a presentation by Dr. Stephen Seiler PhD in this video on polarized training. I highly recommend you watch the video. He is a great researcher.

seiler pic for video_edited-2

More on Shoe Selection – ACSM position

“But Dr. Maggs, I have to wear “X” shoes because I ____________ (fill in the blank with “overpronate”, supinate, have high arches, have flat feet)”

If you’ve been reading these newsletters, or our blog, you are well aware that we have great disdaine for these comments. Shoe prescriptions have been built on very little other than prevailing theories. There is very good research evidence disproving these theories.

Shoe prescription should be based on so much more. This newsletter will not get into the science of WHY these beliefs about shoe prescriptions are wrong. If you are interested in the science, I have written about it previously here, here and here. The British Journal of Sports Medicine published on the topic back in 2008.

The purpose of this post is that, finally, the mainstream healthcare organizations are starting to see the light. The American College of Sports Medicine (ASCM) is the largest sports medicine and exercise science organization in the world with more than 50,000 members. They weighed in on the topic of shoe prescription last month. Here is a link to their new position statement on shoe prescription, but to save you time, I have listed some of their findings below…

Here are some of their general guidelines (in their words) for what to look for in a shoe:

  • Neutral (does not contain motion control or stability components). These extra components interfere with normal foot motion
  • Minimal heel to toe drop
  • Lightweight
  • Foot shape or arch height are not good indicators of what kind of running shoe to buy
  • Pronation is a normal foot motion during walking and running. “Pronation alone should not be a reason to select a running shoe. Runners may be told while shopping that because pronation is occurring, issue with arch support is best. In fact the opposite may be true. Pronation should occur and is a natural shock absorber.”

They go on to list “Shoe Qualities to Avoid”:

  • High, thick cushioning
  • “Extra arch support inserts or store based orthotics. These items are often not necessary. Orthotics should be considered temporary fixes (less than 6 to 8 weeks) until foot strength is increased”

With all that being said, I think there are some potential pitfalls in their recommendations…

  • I am not of the opinion that “everyone” should be an a neutral shoe with minimal heel drop. There are many exceptions.
  • There are specific injuries that can be a result of too much pronation, so I don’t think we should totally discount pronation. The problem is we have no definition of what “too much” actually is. More importantly, there are many causes of “too much” pronation including ankle mobility, proper motor control and stability of the muscles in the hip and calf, velocity of the swing of the contralateral hip, stability and motor control of pelvic rotation, fatigue, anatomic variations etc. If those issues aren’t addressed, you may create more problems by trying to “fix the overpronation.”
  • My point is, if you simply look at the foot to see what kind of shoe someone should be in, you are missing the boat. Runners with good running form and proper training plans can run in just about any shoe.
  • Shoe and orthotic prescription for runners is a delicate business with many factors to consider. If you don’t have a very high level of anatomy education and biomechanics education, you are really rolling the dice. Even with these qualifications, it is a very difficult proposition. In, our experience, the more you read and learn, the more you realize how complicated the issue is. In this aspect, confidence has sort of a bell curve relationship with knowledge.

Unfortunately, there are people who will be resistant to the idea that shoe prescription should be based on more than observing the feet or the idea that a shoe choice that is based on the amount of pronation is incorrect or irresponsible. Unfortunately, there are people in positions of perceived authority who are still advising outdated and incorrect advice. Runners World and Web MD are examples. They still have their websites stating that shoe choice should be based on foot type and pronation.

If this post has you thinking about what type of shoe you should be in, I wrote a brief piece about selecting a running shoe here.

Chronic pain, the Brain, Sadomaochism and Athletics

If you put your foot in a fire, you will feel pain. In order to feel pain, all you need is three things – the body part, damage to the body part and the brain. Pain is pretty straightforward, right? Well, not really. You only need one of those things – the brain. That is correct, we don’t need the damage to the body part, nor do we even need the body part at all! All we need to feel pain is the brain. What if I went a step further and told you we don’t even “feel” pain? Pain isn’t actually a sensation, but rather it’s an interpretation by our brain.

Fear and threat could be the biggest factors that people need to overcome when it comes to pain and also to athletic performance. The fear could be a conscious thought to avoid movement or exercise, or it could be a faulty perceived threat by the brain deeper in the subconscious

This may be a lengthy post, but I’ll try and keep it as interesting as possible because I think this is a topic most people need to read. Whether you are in pain or not in pain, it’s important. I have made some links here so you can skip ahead to the chapters you want to read if you want:

On to the Fun Part…

Before this gets started though let’s get through some premable, things to keep in mind, warnings etc., etc.: This post is not trying minimize pain. Please don’t misinterpret this post as me saying pain is made up, exaggerated etc. and I am certainly not discounting the role that biomechanics and tissue damge play in the etiology of pain and injury. This is merely some musings and things to think about if you are in chronic pain, or are suffering through an Ironman, marathon or even a 5K. If you have pain, please seek out professional expertise. (BTW, I’m not sure what ‘preamble’ means or if what I said qualifies as ‘preamble’, but it sounded scholarly)


Concept #1: Pain is not a sensation. Pain is a perception. There aren’t nerves that tell our brains something hurts – it’s only our brain that gets input from nerves and then extrapolates that information as being pain. Until our brain goes through a very complicated procedure of determining if a certain sensation is a threat, we won’t feel the pain.

While that may seem abstract initially, there are many examples of how our brain can suppress pain, such as a soldier getting shot on the battlefield but then not realizing it until after the battle – at which point the pain becomes severe. Another example could be an endurance runner who just can’t run anymore due to pain and fatigue, yet they manage to dramatically pick up the pace once they see the finish line. Did their tissue damage miraculously heal, or did their brain perform a layered, complicated calculation and determine that the distance to the finish line is achievable and the disagreeable incoming signals from the body are no longer a threat?

Concept #2: Tissue damage does not cause pain, nor do we need tissue damage to feel pain. For example, I have a few patients whose low backs look like they got hit by a truck on an MRI. The discs are herniated, the spinal cord is compressed, there is severe arthritis, yet they tell me their low back pain is only annoying, not painful, nor does it affect their quality of life. Meanwhile, some other patients with severe, chronic low back pain have no evidence of tissue damage on MRI. Another example is tendon problems. It is well documented that imaging tendon damage does not correlate with pain [1,2]. In addition, structural abnormalities seen in tendinopathy are no different when people are in pain compared to when their symptoms go away [3].

Again, I’m not saying tendinopathy or low back pain is being exaggerated or made up. What I am saying is that very often, the pain may be interpreted as tissue damage and that the tissue damage is a threat to the person’s well-being. These thoughts end up magnifying pain and leading to fear of movement or activity. This fear of movement ends up causing the person to avoid exercise and movement, causing a greater impact on their lives than the pain itself ever did.

Concept #3: You don’t even need a body to feel pain. OK, now you’re thinking I’m way out on the edge of sanity, but most people have heard of “phantom limb pain.” Phantom limb pain is the sensation of pain in a body part that isn’t there. For example, many amputees (50-90% of them) or even people born without a limb report feeling pain, cold, sweaty, itchy etc. in the limb that is not there [4]. Therefore, we don’t need a body to feel pain, just a brain.

Why Am I Telling You All of This?

I make my living off of evaluating biomechanics and correcting movement patterns so that there is less stress and strain applied to various body parts. The three concepts I just mentioned would seem counterintuitive to my expertise. However, I have this conversation often in my office mainly for two reasons:

Reason #1: Once people understand these three concepts, it can dramatically improve their symptom resolution. Most patients have something called “fear avoidance behavior”, meaning they are afraid to move a body part out of fear that they will damage it. In many cases (not all), movement can be therapeutic and end up lessening pain. Sometimes, I prescribe exercises that hurt and I want people to understand that’s OK. Hurt does not equal harm. More on this later.

Reason #2: The “nocebo” effect. Most people have heard of “placebo” which is the idea that if you tell someone that swallowing a benign pill or putting colorful stretchy tape on their skin will help reduce their pain, it usually will have that effect. The “nocebo effect” is the exact opposite. Nocebo implies telling someone that some pill, activity or movement will create pain and it ends up doing just that. I can’t tell you how many times people come into the office for a pain and tell me they avoid doing some activity because some orthopedic surgeon, physical therapist or chiropractor told them that if they ran, they would destroy their knees, or if they bent over the wrong way, they may herniate a disc. I love this one, “Mrs. Jones, you’re only 37, but your spine looks like a 76 year old.” How do you think that makes that patient feel? These poorly thought out words create fear in the patient and magnify their pain. This creates a self- fulfilling prophecy where the patient is afraid to drive a car, exercise or even pick up their children. Physicians and therapists have to be careful with their words. They can do a great deal of help, or they can harm. There are many chiropractors and therapists who read this blog and get this newsletter, so yes, I’m talking to you.

The Fun Part of the Post:

OK, so up to now, this has been fairly abstract in its meaning and interpretation. Let’s look at some research that has been done to try and shed some light on what I’m talking about. After a brief summary of each paper, I will extrapolate what this means in the real world.

Study #1: The Cold Probe Study. Researchers used a -20 °C probe to touch the hand of the subjects. There was a light on the table and in some cases, the light was red and in some cases the light was blue. However, it was always the same probe, at the same temperature. When the probe touched the back of the subject’s hand, they reported significantly higher pain levels when the light was red, even though it was the exact same probe.

Real World Meaning: When presented with the exact same incoming signals from the hand, the brain interpreted more pain when it also saw the red light. To most people, red means danger and it means hot. The study highlights the idea that pain is a perception. If the brain interprets a threat (red, hot, danger) it will magnify pain. Similarly, if I tell you that you have a degenerated disc and that is a big problem (even though it usually isn’t)your brain will then interpret low back pain as stemming from the degenerated disc and perceive this as a threat. I have done you a disservice by telling you you have pain coming from a degenerated disc (which is hard to prove) and yet there is nothing that can really be done about it. Would I be lying if I told you the degenerated disc wasn’t a problem? No, I wouldn’t because there is ample evidence that degenerated discs are highly prevalent – just as prevalent in subjects with no pain.


Study #2: The Anticipation of Pain Study. It is well accepted that pain in a joint can inhibit muscle strength and control around that joint. This has been shown in studies where subjects try and generate a force by pushing and that force is measured. The researchers then inject noxious chemicals into the joint and have the subjects try and push again. There is less force generated because the muscles are inhibited by the pain in the joint.

This particular study that I am highlighting did the same thing – having people try and extend the knee against resistance, thus measuring the quadriceps force output. However, instead of injecting the knee, they used random electric shocks on the knee and compared the results with injecting a noxious injection into the knee. Sometimes the subjects were electrically shocked and other times they weren’t. The result was that the subjects generated less force when they were shocked AND when they weren’t shocked. In other words, the quadriceps muscles were inhibited just as much when the subjects anticipated they were going to feel pain from the shock compared to when they were injected with a painful chemical in the knee. Many of these changes in movement lasted after the experiment. I’m not sure who signs up to participate in these studies, but there you have it.

Besides the one study that I just referenced, there are other studies that have shown movement adaptations due to anticipation of pain based off memory. For example, every time we move a limb, we need to make postural adjustments. One study measured the postural adjustments when subjects moved their arm in a particular way. They then experimentally produced painful stimulation of the low back whenever the subjects moved their arm in that particular way. The postural muscles of the back contracted differently in that scenario. When the experimental painful stimulus was removed and the subjects were asked to move their arm again, most subjects returned to their normal muscle activation pattern…but some subjects didn’t. They maintained their altered motor pattern in a manner that stiffened the spine. The authors concluded that this protective strategy would predispose the subjects to spinal injury if maintained long term.

Real World Meaning: These studies highlight the idea that our movement patterns and motor control can change when we simply anticipate pain. All you have to do is convince someone that something is going to hurt, and they will move differently. That means that if someone does have a knee injury, shoulder injury low back pain etc., their movement strategies may change in a way that becomes detrimental. Even when the pain goes away, our movement patterns are different. This makes it very difficult as a clinician for a few reasons. First of all, we know that the #1 risk factor for hamstring strains, ankle sprains, low back pain etc. is whether you’ve had the pain before. When the pain goes away, many people feel treatment is done, and they can stop doing their rehab. Unfortunately, movement patterns often need to be re-learned, so the absence of pain should not mean that rehab is over. Secondly, due to the anticipation of pain, fear of movement becomes overwhelming for many people, so they stop using the body part, which results in increased joint pain and muscle disuse so the problem becomes a self-fulfilling, snowballing problem.

Study #3: Mirror Training Studies. As I mentioned earlier, phantom limb pain is experienced by 90% of amputees. A mirror box is a contraption which fools the patient’s brain into thinking that they are moving their real (but amputated) limb simply because they are seeing a reflection of their opposite limb moving. This has been shown to be highly effective in reducing phantom limb pain.

Real World Meaning: Mirror training is not only effective in amputees, but also in people with inexplicable limb pain or low back pain. Once a person has been in pain, their brain’s sensory maps for that body part are altered. This altered mapping has been seen in trials where subjects with hand pain are unable to quickly recognize pictures of the side of their body that the pain is on. For example, if you have a painful right hand and are shown random pictures of right and left hands in different positions, you would most likely be less quick and less accurate in identifying pictures of a right hand compared to the left. If you don’t understand what I’m talking about, go to around the 2:00 minute mark of the video below.



In order to figure out if the hand in the picture is a right or left hand, we must mentally move the hand into a position we can recognize. People with chronic pain are less able to do so on the side with the chronic pain [5]. This could mean that a contribution to ongoing pain in the absence of tissue damage could be due to incongruence between motor intention (the way you want to move) and proprioception (your brain’s perception of spatial orientation and position of your body parts). In other words, incongruence between motor commands and sensory perceptions.

Again, this may sound abstract, so let me give a couple examples. People with chronic low back pain have impaired proprioception of their back (they have poor positional sense of their back) [6, 7, 8, 9], however, it has been shown that this impaired positional sense is not present in people prior to suffering from low back pain [10]. In other words, the impaired positional sense is an effect of the low back pain, not the cause. By using mirrors, researchers have been able to help this impaired positional sense and thereby significantly reduce pain. They did this by having low back pain patients go into two different rooms where they were instructed to make 10 pain producing repetitions of movements with their low back. In one room, they were able to see their back moving via a system of mirrors and the other room they weren’t. The group that saw their spine moving ended up having significantly less pain with movement after the intervention. Why did they end up having less pain when they were able to see their back moving?

Unlike the mirror “illusion” therapy used in the phantom limb pain, this study merely allowed the patients to improve the congruence between their intent to move and the way their back actually moved. In other words, it helped their brain “map out” the spatial orientation of their back. The other possibility is that by seeing the spine moving normally in the mirror may reduce the “perceived threat” in the brain. This is backed up by studies that show subjects perceive less pain if they watch the moving painful body part, thereby (potentially) reducing fear of movement and the perceived threat associated with using the body part [11].

Along those same lines, there is evidence that people with chronic pain will perceive more pain in a painful hand by moving the hand while looking at it through a magnifying glass. Not only will they feel more pain, but the swelling can actually increase [12]. Conversely, they can reduce their pain by viewing the painful hand moving while looking at it through a minifying lens.

Once the brain perceives that the body part is in pain, infering that there is tissue damage and thus is a threat, the brain map changes for the involved body part. Very often, we prescribe exercises where the patient uses the painful body part in a non-painful way which “convinces” the brain that the body part is not a threat and it can use the body part without threat. Teaching a patient to utilize the body part in a non-painful way can help the brain overcome fear of movement with that body part.


Study #4: The Sadomasochism Study.

Pain is felt differently according to social and personal contexts and how the brain interprets the threat. One need not look any further than sadomasochism, self flagellation, cutters etc. In this video below, “Mind and its Potential”, one of the leaders of pain research, Lorimer Moseley, talks about a study he conducted on sadomasochists. In this study, they recorded actual brain activity as well as the response of the subjects. In the study, the sadomasochist subjects had a hot poker put on their leg in two different circumstances. Circumstsance #1 was when Dr. Moseley’s recorded voice was saying “Now, I am putting a hot poker on your leg” and in circumstance #2, there was a mistress’ voice saying the same thing. The subjects brain activity was similar in both circumstances, but the experience reported by the subjects moved from pain in the first circumstance, to pleasure in the second circumstance. He goes on to say “these people don’t find pain pleasurable, but they do find noxious stimuli in that context, pleasurable. They’re not hurting, because they are in pleasure“. I highly recommend you watch this video if this subject is at all interesting to you, or you are in chronic pain. He is really entertaining and funny.

This type of situation is observed quite frequently in the office. When we perform soft tissue treatment on runners or bodybuilders or other athletes, they frequently say, “ya, that hurts right there.” When I respond with “Do you want me to back off?“, the answer is usually, “No, it kinda feels good.” Contrast this with some other folks, where the response to my “do you want me to back off question“, is a very angry, “Yes, I want you to back off!” The athlete is very accustomed to pain and often associates enduring some pain as being necessary to achieve improvements in physical strength, endurance etc. The context of feeling pain is entirely different for more sedentary folks who perceive the pain as a threat.

This has been researched and shown that athletes can handle pain better than non-athletes. After reviewing many studies, the authors of this particular review concluded, “regular physical activity is associated with specific alterations in pain perception.

Real World Meaning: The “No Pain, No Gain” mantra is very well known amongst athletes. I have known many ultra distance runners who have told me they did a long, grueling race and their legs “hurt so bad!” and they finish up their statement with, “the pain felt great!!” The ability of endurance athletes to go into the “hurt locker” or the “pain cave” is what sets some great athletes apart. However, while some athletes seek out the pain, most try and simply endure the pain with mantras in their head, or counting steps etc. Some athletes endure the pain, whilst others seek it out.

This gets really interesting when researching endurance running. I will hopefully do a follow up post soon on the “central governer” theory of fatigue in endurance running. In the meantime, we must all remember to distinguish the difference between “normal” and other pain signals. As I said at the beginning of the post – pain is a subjective output of the brain, but it is usually there to tell you something and should not be ignored.

Summary:

  • Pain is an opinion of the brain. Usually, tissue damage fires nerves that tell the brain something happened. It is up to the complex, layered processes of the brain to figure out what to do with that information. If it perceives the information to be a threat, it is interpreted as pain.
  • Very often pain leads to altered movement patterns which can perpetuate the problem. Very often, we prescribe exercises where the patient uses the painful body part in a non-painful way which “convinces” the brain that the body part is not a threat and it can use the body part without threat.
  • Chronic pain leads to changes in the brain that fundamentally change the way the brain perceives the painful body part. There are various methods that can be employed to change this perception

The High Price of Physical Inactivity

There is a pestilence upon this land” – Roger the Shrubber

According to a new report this past week the fitness levels of children in the USA have declined about 6% per decade between 1975 and 2000. That’s before the widespread use of smartphones, tablets, online gaming etc., so I would imagine it’s even worse in the past decade. After analyzing 50 different studies on running fitness between 1964 and 2010, they report that kids run a mile, on average, about 90 seconds slower than their peers from 30 years ago.

The world has stopped moving. There has been a rapid decline in physical activity in today’s youth compared to all previous generations. The current generation of children simply doesn’t move as much as they should. While that may sound like the old guy complaining that the kids music is too loud, and they wear their pants too low etc, the message of this post is actually a very serious one and should not be taken lightly. There are too many implications that are involved that most people don’t think of when they think of physical activity. Sure, there are the health implications, but there are also implications for cognition, financial earnings potential, and quality of life. I wrote a similar post earlier this year with a very sobering video.

It has been documented that the people have false hope in medication and undervalue physical activity. That study was titled, Physical Inactivity: The Biggest Public Health Problem of the 21st Century.

Health Implications:

I am not going to spend much time here. I think we all know there are major health implications to physical inactivity. It’s not just cardiovascular implications. Exercise has been linked to lower levels of depression, anxiety and other mental illness, arthritis, type II diabetes, sleep disorders, improved quality of life in general etc. These are well documented, so I’m not about to reference them all. If you’re really interested, here is a link to a 623 page document detailing the health benefits of physical exercise.

Cognitive Implications:

In children lower physical fitness has been linked to lower cognitive function for tests requiring memory, perception and cognitive control. Again, there are many, many studies showing this, so for a good review, here is a link to a full text article outlining much the data. Along with the physical inactivity and higher BMI being linked with poor cognition, one would expect that it would then be linked with lower academic achievement in general. If you think that, you would be correct and it has been shown here, here and here.

There is a significant partnership between physical inactivity and screen time – TV’s, laptops, iPhones, iTouch, gaming systems etc. It should not be surprising then that there is a significant relationship between screen time and cognition and mental health. There is a great review article on this topic found here. I found it interesting that for every hour a child spends in front of a screen, there is a 9% increase in subsequent attention problems consistent with ADHD [found here].

Financial Implications:

Due to the improved academic achievement that corresponds with higher physical activity, we could assume that there would be a corresponding potential for higher wage earning. The same could be said for the improvement in cognition including memory and focus. There is another aspect of wage earning which is the work productivity. There are a number of studies that shoe a dose response relationship between physical inactivity and absenteeism/sick leave [found here, here, here and here].

My Cynicism:

There are a number of recent studies on physical inactivity that should be sounding alarm bells in the media and garnering a full scale assault from the media. However, without the financial backing of major pharmaceuticals or business, the results of these studies are largely being ignored by the media. If physical activity can’t buy a commercial slot on TV, or a full page ad in a magazine, the media will ignore it.

In addition, the world of healthcare is fraught with spurious prescribing activity that is heavily influenced by pharmaceutical companies [here]. For example, there are serious questions raised about the financial interests of those doctors on the panel of the National Cholesterol Education Programme. You can find the financial disclosures of the panel members Adult Treatment Plan here. Keep in mind that the new cholesterol guidelines that just came out that will place many, many new people on statin medications. If you think I’m going off on a tangent here, maybe I am, but this drug mentality is trickling down to children, since there are now doctors recommending statin medications for children as young as 8 years old. There recently has been new cholesterol screening guidelines (that have been endorsed by the American Academy of Pediatrics) which recommended universal screening for kids 9-11 years old.

Various studies have shown that exercise is as effective as statin medication, and this was summarized well just last month in the British Medical Journal. The full text of that article can be found here.

Summing it all up

So, kids these days run a mile 90 seconds slower than their peers in 1964, overall physical activity is declining worldwide and it is correlated with a a projected reduction in life span as well as increases in arthritis, obesity, type II diabetes, cardiovascular disease, cognitive and emotional problems.

If you don’t get your kids out to play, jump and run, who will? They may not like you when you take away their video console and kick them outdoors, but they will be better off for it.

 


Shin Splints – What You Need to Know

Shin splints (technically called “Medial Tibial Stress Syndrome, or MTSS) is a very common injury in runners. I see a lot of runners with this injury and the vast majority of them are relatively new to running.

The first thing we need to understand about MTSS is that it is a bone injury. It used to be thought that the pain was on the periosteum of the bone (the most outer layer) because the muscles of the leg underwent tiny tears where the attach to the bone. For the most part, that idea has been shown to not be true. Newer and better imaging has shown that the injury is in fact, the bone itself [references here, here, here and here]. In other words, a bony overload injury. Under normal circumstances, the strain of running causes microdamage in the bone which leads to an adaptation process to strengthen the bone. When the damage exceeds the ability to lay done new bone, localized areas of osteopenia result (osteopenia is a reduced bone density).

From Gaeta et al. – American Journal of Roentgenology 2006

So, when people talk about shin splints vs. stress fractures of the tibia, they are essentially the same injury but with greatly varying degrees. Shin splints are localized areas of osteopenia and bone growth activity, a “stress reaction” is a bit worse and it’s when the bone marrow begins to have edema (swelling) and then finally, you get a stress fracture where there are actual fracture lines present in the cortex of the bone as seen on the MRI/CT. So, they are different stages of the same cause – overloading of the tibia with an inability of the bone repair to keep up with the stress applied to it.

There are two approaches to dealing with MTSS, and they both should be followed: 1) Reducing the load on the bone and 2) Increasing the bone strength.

Reducing the load on the bone:

There are a few risk factors for MTSS. Some are well established some are not. Some previously cited risk factors include “over”pronation, high BMI (Body Mass Index), leg length inequalities, low calf strength, less experienced runners, high load/loading rate, use of orthotics, poor motor control in the hip, poor bone mineral density and some others that I’m not going to get into. So, let’s briefly look at some and look at others in more detail:

i) “Over”pronation.

This has been a term that is thrown around without much thought. Unfortunately, we can’t even agree on what “normal” pronation is, and f we can’t figure out what normal is, how do we know what “overpronation is? I made a lengthy blog post about this that you can read about here. Studies on whether or not “over”pronation causes MTSS are mixed.

Most of the studies linking excessive pronation with MTSS are researched by using subjects who are currently suffering from MTSS. The problem with that research method is that you don’t know if they are “over”pronating because they are already injured or if the “over”pronation caused the injury (i.e. is it a cause or effect).

Alternatively, prospective studies can be performed in which researchers measure the variables and then track the athletes for a period of time to see who gets injured. In these prospective studies, some studies found that pronation or foot type was not associated with MTSS (here, here and here), while other studies did find a relationship (here, here and here). To further complicate matters, another study argued that it’s not the amount of pronation that we should be looking at, but rather the timing of the pronation that is a risk factor for MTSS.

I have argued in previous posts (here and here) that evaluating pronation is not only unreliable, but there are many proximal factors (higher up in the kinetic chain) that may contribute to pronation. Ankle dorsiflexion mobility and poor motor control in the hip are two factors that can increase pronation significantly.

If control of the hip is not syncronyzed with pronation and supination, there may be some longitudinal twisting of the tibia, since the tibia is between the foot and the hip. There are a few studies that reinforce that hypothesis as they have linked poor motor control at the hip directly to MTSS (here here and here). So, if you are concerned that you may be pronating too much, I would suggest you go have yourself evaluated by someone who understands anatomy, running mechanics and injures to see exactly “why” you are pronating too much (if you even are). Consulting with a health professional who merely applies ultrasound or some electricity on the skin over the area where it hurts is most likely missing the underlying cause.

ii) Leg Length Inequality.

This topic is a bit of a pet peeve of mine. There is extremely poor reliability in measuring leg length and the research suggests that the difference in leg length has to be substantial before there is any meaningful compensation. You can read more about my feelings on it here. Frankly, I don’t really care if someone has a minor leg length difference. I find it of little value. Again, please read why I feel that way here

iii) Low calf strength.

This is a factor that has been shown to correlate to MTSS in a few different studies. It has been correlated with increased tibial stress fractures here, smaller calf girth has been correlated to MTSS here, poor calf muscle endurance has been correlated to MTSS here , and it’s likely because the calf muscles can absorb the shock of landing better than the bone – here. So, starting a calf muscle strengthening program would probably be a good idea in most people suffering from MTSS. I don’t think there is anything to be lost by doing some strengthening work, some power work and some endurance work on the calves. At worst, you have done some extra exercising.

iv) Loading Rate.

Loading is synonymous with force. Research does not support the idea that the “peak amount” of force applied during midstance of running is associated with injury, but research does suggest that loading “rate” is associated with some injuries. The “rate” of loading is the amount of load applied vs time. In other words, how fast the load is applied. If we look at the video below, you can see there is a graph in the video. It is load on the vertical axis and time on the horizontal axis. If the slope of the curve is steep, that means you are applying a load under a shorter period of time (i.e quicker) which is a higher “rate” of loading.

[vimeo]https://vimeo.com/75853507[/vimeo]

This is very important for MTSS and tibial stress fractures. A) Hreljac et al., did a study looking at runners with recurrent injuries vs. runners who had been injury free through their careers. The only biomechanical variables they found that were significantly different were peak impact force and impact loading rate. B) Irene Davis did a prospective study (here) where they followed 242 runners for 2 years. Before they followed them for the 2 years, they measured different variables. Over the 2 years, 57% of them sustained an injury including iliotibial band syndrome, anterior knee pain, tibial stress syndrome and plantar fasciitis. Statistically significant differences included average vertical loading rate and tibial shock values. They stated, “Based upon the odds ratio for VALR (vertical average loading rate), reducing impacts is likely to result in an overall reduction of injury risk.” C) Last year, Bredeweg et al., did a prospective study by measuring variables and then following the runners for 9 weeks (too short if you ask me). There were 203 runners and they found that amongst the males, the injured runners had higher loading rates and shorter ground contact time.

With respect specifically to the shin, studies have found that loading rates are associated with injuries to the shin (here, here and here).

Loading rate can be changed in many runners by increasing cadence and/or being instructed to “run quietly” or “run softer”. For the most part, I have found these strategies to be effective in runners suffering from MTSS or tibial stress fractures. A 2010 study gave runners verbal instructions to “run softer” as well as providing them with visual real-time feedback for reducing the loading rate and there was good success (although the study only had 5 subjects). A 2012 study used 3 different interventions to try to reduce loading rates: increase cadence, use a racing flat or land with a midfoot strike. They discovered that landing with a midfoot strike was the most effective method at reducing loading rate, however, the study only included 9 individuals and the average cadence was 172, which is unusually high for recreational runners, so increasing cadence may not have had as much of an effect on these subjects as it would on someone with a lower cadence. In order to avoid getting too winded on this topic, if you are still interested in reducing the loading rate, Greg Lehman did a nice post on the topic which you can read here.

The topic of shoes often comes up when talking about shin splints. There is a theory that by going with a minimalist shoe, your body will inherently reduce it’s stiffness in order to absorb the shock that the shoe isn’t absorbing. The theory is based on a few jumping tests where they had subjects jump off platforms and land on concrete surfaces or very soft surfaces. When landing on the harder surface, the subjects increased the knee, hip and ankle bending when they landed in order to absorb the shock (they decreased their leg stiffness). When landing on softer surfaces, the subjects increased their leg stiffness. This is thought to translate into running, but it hasn’t really worked out that way. These studies did not find that [here and here]. In addition, some people simply don’t change their leg stiffness regardless of the shoe type. So, if the name of the game is to reduce the loading rate, some people may benefit from going to an ultrasoft shoe, such as the Hoka line of shoes. Personally, I believe they can reduce the loading rate as long as the body mechanics are also helping to reduce the loading rate. This is supported by some research showing that a shoe can reduce loading rates if the running mechanics are the same [here]. The topic is still a contentious one, however, since there are many studies showing that going with No shoes significantly reduces the loading rates, if done properly. “Most” runners will adopt a forefoot strike, increase cadence and reduce loading rates when going barefoot, but this is not always the case. We are all individuals, and we never know how everyone will react. I recently made a post on that very topic when discussing shoe selection, which you can find here.

v) Use of Foot Orthoses.

OK, we are STILL kind of on the topic of loading rate. This is because the foot’s ability to pronate is a major shock absorber for the body. By using orthotics, you take that ability away. There are a few studies that show orthoses HELP MTSS, but there are also a few that say it HURTS MTSS. I think it depends on the cause. You need to absorb shock somewhere, but your ability to absorb shock in your feet may be reduced if you are using most foot orthoses. This study found that 53% of 146 collegiate runners wearing orthoses developed MTSS compared to 21% of those NOT using them. Most orthoses are designed to limit pronation, but this study and this study say pronation is NOT correlated to MTSS, so, the orthoses thing is really up in the air. in my opinion.

Increasing the Strength of the Bone

i) Gradually Increase Mileage

When a bone undergoes some stress, it needs time to build back up. Studies show that after you start increasing stress to a bone, it takes about 30-45 days to get building up it’s strength. That means that when you initially start a running program, there is a period of 1-2 months where the bone is being broken down by the stress and it hasn’t had time to build itself back up yet (see here]. That is a significant amount of time when the bone is MORE vulnerable to injury. Therefore we need to take a very slow approach to training. I typically use this program from Blaise Duboise to get runners back into running after a serious injury. I know it seems very elementary, but it makes sense to take a couple months to slowly build up bone strength.

ii) Manage Your Pace

In addition to running frequently in brief periods, pace is also important, since loading rate increases with increasing pace. My experience has had good success for those with MTSS to start training under aerobic threshold until their bones have built enough strength to add in speed work or tempo runs. You can read more about training slower and building a proper aerobic base here

iii) Evaluate the Health of Your Bones

For those who just can’t ever seem to get over the MTSS, I’d suggest you consult with an orthopedist or endocrinologist and get a bone density test and blood work to test testosterone, parathyroid, calcium, vitamin D levels and whatever he thinks might be necessary. Since MTSS is characterized by localized bone loss, I don’t think it’s unreasonable to consult with an MD about your bone health. There are many factors that could find out why you are vulnerable to bone injury.

Summary

In summary, MTSS is a bone injury with many possible biomechanical or physiological roots. Evaluation of overall running mechanics including leg stiffness, cadence and motor control in the hip are important Interventions such as gradually increasing mileage and pace as well as performing some calf strengthening are also important. Assessing your bone health through blood work and imaging may be necessary for some individuals who suffer from recurrences.

Having yourself evaluated properly is vital to understanding why you are having the injury and also how to correct the problem.

 

Is This Shoe Good For Me?

Imagine you’re back in high school chemistry. You take 5 units of compound A and mix it with 5 units of compound B. You knew exactly what chemical reaction you were going to get. Unfortunately, the consistency that exists in a chemistry lab does not exist when you are dealing with people.

That’s a problem when you are a healthcare provider. Nobody ever knows for sure how a person is going to react to a drug, a surgery or a rehabilitation exercise protocol. Give the same rehab protocol to 10 different people with Achilles tendinopathy and you will not get the same outcome. More likely, you will get 10 different outcomes. The reason we don’t know is because there are so many variables – acute vs chronic, what part of the tendon, nutritional status, stress, genetics, occupation, mobility, stability/motor control, psychosocial fear about their condition, daily postural habits, medications etc., etc.

This brings me to the topic of this post: Footwear.

The same rules about not knowing how people react to a therapy are the same for prescribing footwear. Making generalized statements about what people should wear on their feet is unreasonable, yet that’s what has been going on in research papers, running shoe stores, doctor’s offices and even in runners telling other runners what they should wear or how they should run.

We can pretty much break down shoe choice based on these typical categories:

  1. Foot type
  2. Pronation
  3. Minimalist vs Standard
  4. Foot Orthoses (footbeds, orthotics)

1) Foot Type:
I hear of, and see people choosing their shoe based on their foot type (high arched vs .flat foot). While this notion seems to fit into a nice little package, it simply doesn’t work that way. Using a shoe type based on the shape of your foot has been studied a few times with less than desirable results. The so called “wet-footprint test” has been the basis for shoe prescription for the past 3 decades, despite the evidence showing its inappropriateness. Unfortunately, many shoe retailers and clinicians continue to look at the shape of a client’s/patient’s arch and use this shape as a basis for prescribing a “motion control”, “stability” or “neutral” shoe.

There are two well designed, prospective studies that have disproven this notion of prescribing shoes based on foot type (Ryan et al, 2011 and Knapik et al, 2010). Despite what some people would have you believe, if you have flat feet you don’t need high arched shoes and if you have high arches, you don’t need cushioning. You might, you might not. There are no sweeping, universal rules that apply. Trying to teach this to people when they have preconceived notions is very difficult.

2) Pronation:

Pronation is the inward rolling of the foot and ankle during the weight bearing part of walking or running. I have previously written extensively on the essence of the problem with pronation. We can’t define what pronation is, let alone what “over”pronation is. Since there is no consensus on what “over”pronation is, and if there are multiple factors that cause it (whatever “it” is), and if research is conflicting on “its” association with injury, how can you expect to tell everyone that “it” is bad?
If there is merit in choosing a shoe based on the amount that you pronate, there should be a few things established: a) that pronation is important and linked to injury, b) Trying to reduce pronation is advantageous and c) That shoe choice consistently influences the amount of pronation.

Let’s look at each of these individually

  • Pronation is linked to injury: Results are conflicting and inconsistent. There are studies showing that “over”pronation is associated with injury (Messier et al. 1988, Willems et al. 2006). However, there are also many studies that show no association (Hestroni et al. 2006, Reinking et al. 2010, Nielson et al. 2013) There are also studies showing that reduced pronation is associated with more injury (Thijs et al. 2007), and that excessive pronation is protective of injury (Hreljac et al. 2000). This lead to a recent review of the literature to conclude, “Based on the review of literature, there is no definitive link between atypical foot mechanics and running injury mechanisms.” (Ferber et al. 2009). So, the issue of pronation and “over”pronation is inconsistent with injury in the research. That is not to say that it doesn’t exist. I’m merely pointing out that assigning a shoe solely based on the amount of pronation is tenuous at best. I will repeat this ad nauseum: we are all individuals and you can’t make general statements like “pronation is bad” or “pronation is not bad”.
  • Trying to reduce pronation is advantageous: When someone is observed “over”pronating (too much, too fast or too long), there is seldom any thought as to “why” this is happening, or even if efforts “should” be made to reduce it. “Over”pronation can be caused by many different issues. For example, limited ankle dorsiflexion mobility can cause increased compensatory pronation (Karas et a. 2002, Blackman et al. 2009, Whitting et al. 2011). If the excess pronation is merely a compensation for limited ankle mobility, why wouldn’t you just fix the ankle mobility instead of trying to stop the compensation? (see a detailed explanation of that concept here). I would argue that if the excessive pronation is compensatory for limited ankle mobility and you try and take away the compensatory pronation, you are asking for an injury. Another reason could be higher up the kinetic chain. Another cause may be poor motor control in the hip – less force generated by the gluteal muscles can result in the thigh moving toward midline and internally rotating, which moves the knee with it and possibly, the foot and ankle into pronation (Delp et al. 1998, Zeller et al. 2003) The gluteus maximus plays a large role in decelerating internal rotation of the thigh and shin and thus decelerating pronation early in the stance phace of gait (Preece et al. 2008) and there is another study that suggests that during the latter stage of the stance phase of gait, the ankle and foot are controlled by the leg, not the leg being controlled by the foot and ankle (Bellchamber et al 2000). In other words, pronation is highly influenced by structures higher in the leg. It would be a backwards approach to try and “fix” the pronation with a shoe if there is faulty motor control higher in the leg.
  • Shoe choice consistently influences the amount of pronation: I will not bore you and talk about all the different studies on this topic. Suffice it to say that the results are all over the map. Rather, I will rely on a 2011 study (Cheung et al, 2011) which took a review of the literature regarding motion control shoes and their ability to control pronation (thanks to @Rway810 for the article). While they concluded that overall, there was some effectiveness for motion control shoes to reduce pronation, they also stated, “Studies on the efficacy of motion control shoe are equivocal with different results being reported on the effectiveness of motion control shoes for controlling foot pronation. In addition, they concluded that the data did not support the idea that motion control footwear can influence movement in the segments of the leg higher than the foot. They stated, “the relationship between tibial and foot movements is not uniform across individuals and there is likely to be high inter-subject variability.” High inter-subject variability is really saying – “we don’t know what will happen when we use motion control shoes”. This is because there are many influences to foot mechanics higher up in the leg. I went over this in the paragraph above.

All that being said, there are some people that will do great in motion control shoes and some people will not. Some people will do great in neutral shoes and some people will not. This is partly because the amount of pronation an individual has is controlled by many different factors. Sometimes it’s the anatomy of the foot, but other times it’s due to anatomy or motor control somewhere else. That is probably why orthotics and motion control shoes have such high variability in their results.

My point is that prescribing shoes based on the amount of pronation for no reason other than a philosophy of “overpronation is bad” is a philosophy without merit. If you base your shoe choice on this philosophy you are doing so without any scientific basis and worse, you may get injured. Unfortunately, that is the basis for most shoe prescription in today’s world. However, to repeat…trying to convey this message to people who have preconceived ideas is very difficult.

3) Minimal vs. Standard Shoes:

The last 7 years have seen an upheaval in the running shoe industry with the “minimalist” movement. I’m not going to explain it all here. If you’ve read this blog before, you know all about it. Unfortunately, there are fanatics on both sides of this argument. Who is correct? Well, it depends….

There are no good studies that show minimalist shoes are more economical or prevent injury better than standard shoes. On the other hand, there are no studies showing that standard shoes are more economical or better at injury prevention than minimalist shoes. We are all different and we all will respond differently. For Pete’s sake, that’s the whole point of this article!

The most applicable research paper on this topic came out last year. In this 2012 study, researchers looked at runners wearing a “standard” shoe (Asics GEL-Cumulus 10i) and a “minimalist” shoe (Vibram FiveFingers) and compared the running economy with them using either shoe. After tallying all the data, the researchers concluded that runners wearing minimalist shoes, “are modestly but significantly more economical than traditionally shod runners regardless of strike type, after controlling for shoe mass and stride frequency.” So the researchers concluded that minimalist shoes were more economical, however when you get into the details of the study, not everyone was more economical in the minimalist shoes. In fact, “within-subject differences in cost ranged from being 9.66% more economical to 7.32% more costly.” Yes, you read that correctly…when wearing minimalist shoes, some subjects were 9.66% MORE efficient while others were 7.32% LESS efficient. What a surprise…we all react differently!
The researchers took a statistical average to make the “minimalist is more economical” conclusion, but that doesn’t pertain to everyone. So will a minimalist shoe more economical for you? Well…it depends!

4) Orthoses (footbeds, orthotics)

Keeping with the theme of high variability when applying the same treatment to different people, we see the same thing with foot orthoses – whether they are prescription or over the counter. Liu et al., (2012)used intracortical markers (pins embedded in subjects foot bones) to measure kinematic changes associated with orthotics but unfortunately, it only involved 5 subjects (I’d imagine people aren’t lining up to have pins stuck in their bones). The authors found that, “Changes in calcaneus-tibia motion were comparable with those described in the literature (1°-3°)… However, the nature and scale of changes were highly variable between subjects.” They found that sometimes, the changes were in the subtalar joint and sometimes in the ankle joint. In other words, subjects reacted differently.

That is not to say that foot orthoses don’t help some people. There is some research that shows they do help reduce pain in many people…but not consistently. However, the mechanism is more likely through alterations in muscle control rather than consistent changes in mechanics.

Summary and Recommendations

Here is a summary up to here: We are all different. There are no universal recommendations for shoes for everyone, nor is there a universal recommendation for subgroups (pronators, forefoot strikers, ultramarathoners, females, fat people, caucasions, people with tight hamstrings, redheads, people with yellow hats or whatever sub-category you want to make up).

Can individual shoe recommendations be made? Yes, but with caution. Shoe choice depends on comfort, injury location, injury history, evaluation of movement patterns, joint ranges of motion, training load and overall style of running. For example: a person with an arthritic big toe should propbably have a shoe with a forefoot rocker, a person with anterior ankle impingement should probably have a higher heel to forefoot angle and a person with a history of tibialis posterior tendinopathy should probably be in something that controls pronation. However, these recommendations should be part of an overall biomechanical assessment of their kinetic chain, rather than looking at their foot as an isolated segment that isn’t influenced by other segments of the body.
So if there are no universal recommendations, how do you pick your shoe?

Well, there are a few different scenarios here:

  1. You have been running for a while and have a history of injuries and shoe selection and currently injury free. You should know what works for you and stick to it. Don’t buy into the hype of new technology, or if you do, incorporate those newer shoes slowly into your weekly mileage and only as an occasional change of pace from the shoes that have worked for you in the past.
  2. You are new to running without a history of injuries or shoe choices. Go with what feels comfortable to you and be judicious with adding weekly mileage. The body is great at adapting to new loads you place on it, but it does so gradually. Don’t be sold by the minimalist crowd and don’t be sold by the anti-pronation crowds. Don’t buy into the upselling of orthotics either. My personal viewpoint is that we should try and run in as little shoe as we can get away with – no more and no less. There is no research that says minimalist shoes reduce injuries and no research that says pronation control, elevated heel, cushioned shoes reduce injury. Go with what feels comfortable to you.
  3. You are currently and repeatedly injured despite different shoe types. Well, this is what I see in my office quite often. We have to realize that the shoes play a small role in injury and your body mechanics and training errors play a much larger role. You need to have a serious discussion with someone who understands running injuries and can look at your movement patterns, running biomechanics, training patterns and maybe even order blood work or imaging. If you go to a healthcare provider with pain somewhere and all they focus on is treating the spot that hurts, they are probably missing the boat.


Clinicians Guide to Ankle Dorsiflexion

Imagine running, squatting or going downstairs in a ski boot. Do you think your legs and pelvis would move differently? Have you ever tried to do those things with ski boots on? It’s pretty tough. What if you were allowed to loosen the boot a little? There would still be altered movement, but just not quite as bad. That is the nature of this post: Limited ankle dorsiflexion and its effects on kinematics and injury.

Previously, I made a post called The Definitive Guide to Pronation. This is another lengthy, detailed post, but now I’m moving up the kinetic chain. This post is on restricted ankle dorsiflexion (DF). It is really designed for clinicians, but if you are not a clinician you’re in luck. I created a “patient version” located here.

If you’re still reading, I’m assuming you have a working background education of anatomy and biomechanics.

There are a couple reasons that made me research this article: 1) The huge numbers of patients that I see with restricted ankle DF and 2) An open challenge by Dr. Greg Lehman in this post where he wrote, “Can you with certainty conclude that a lack of dorsiflexion is a true dysfunction? I think a massive post on restricted dorsiflexion and injury, form and performance would be cool. Any takers?”

Did he say “massive” post? Yes, but most readers will lose their attention span if I made it massive, so this isn’t massive. It’s just over 7,000 words. But, it’s still detailed and comprehensive. Let me warn you ahead of time, the research is plagued with problems. Various researchers have different definitions of what “limited” ankle DF is and how to measure it. Consistency is not a pillar of strength when it comes to this topic.

Because of the breadth of the post, I have made headings with hyperlinks within the post:

  1. What is “Normal” Ankle Dorsiflexion Range of Motion?
  2. How Does Reduced Ankle DF Alter Other Lower Extremity Kinematics?
  3. What Injuries are Correlated to Reduced Ankle DF?
  4. Can Limited Ankle DF Be Corrected?
  5. Conclusion: Is Limited Ankle DF a “True Dysfunction”?



Section 1. What is “Normal” Ankle Dorsiflexion Range of Motion?

Establishing normative data on range of motion (ROM) should be a simple task. I mean how hard can it be to reliably measure ankle DF? Well, very difficult when you consider the possibilities: Do you use a goniometer, inclinometer or tape measure? Open chain or closed chain? Knee straight, knee bent or both? Do you eliminate pronation or allow the subject to pronate? Healthcare is a funny business. We can make arguments out of the simplest things.

Without dragging out what should be the simplest variable in this whole article, I’ll get right to the point – there is no standardized method for measuring ankle DF, but the weight-bearing lunge position seems to be the most used, simplest and most reliable method for measuring ankle DF.

In non-weight bearing tests measuring ankle DF, the clinician is required to manually push the foot cephalad in order to get ankle DF. The amount of torque the clinician can generate is highly variable and to make things worse, they have to have a hand free to use a goniometer or inclinometer. You can see how this is a problem.

Conversely, in the weight bearing lunge test, the subject’s body weight provides more DF torque than any tester could, so we don’t have to worry too much about the tester not pushing hard enough. In addition, the clinician can have hands free to measure ROM.

Since pronation imparts dorsiflexion at the subtalar and midtarsal joints, another hurdle in measuring ankle DF ROM is limiting pronation. In other words, attempting to hold “subtalar neutral”. It has been shown that pronation can add as much as 8-10 degrees of dorsiflexion.

It is notoriously difficult to find and maintain subtalar neutral when measuring ankle DF, however, the weight bearing lunge test is a consistent, reliable method of measuring dorsiflexion. By making sure that the subject lunges forward with the thigh going straight ahead (see video below), pronation can be limited. If you don’t trust my word, try the test on yourself with the thigh moving straight ahead in the sagittal plane and measure then do the test while allowing yourself some femoral adduction and pronation. You will find your knee travels forward significantly more while in the femoral adducted and pronated position.

This technique is very reliable. Konor et al (2012) measured the distance from the toes to the wall with an intra-rater reliability (via intra-class correlation coefficient) of 0.99. By using an inclinometer or goniometer, the reliability was not quite as good. They did not specifically place the foot in a subtalar neutral position or utilize a small wedge placed under the medial aspect of the foot to maintain a more neutral position of the subtalar joint. Rather, they simply told the subjects to “progress his or her knee in an anterior direction.”

Bennell et al (1998) found an inter-rater reliability (via ICC) of 0.99 and again found the test less reliable when using an inclinometer

So, we have a very simple, extremely reliable test (inter and intra rater) that requires little to no equipment and is done weight-bearing. What else could you ask for? Well, validity is the answer to that question. We always come back to the question, “What are we actually measuring?” Since we are unable to totally eliminate subtalar and midfoot pronation we cannot be 100% accurate that we are measuring true talocrural dorsiflexion but it’s the best test we have. If you have read my lengthy blog post on pronation, you will realize that there is a healthy overlap of combined dorsiflexion and pronation at the talocrural and subtalar joints. The talocrural joint isn’t just a sagittal plane mover as we were taught in school.

Validity is going to be tough in any test designed to measure ankle DF. For example, Lundgren et al (2008) anchored pins in the bones of 5 subjects and measured the motion of the bones of the foot while walking. They found, “The ankle is often assumed to be the primary source of sagittal plane motion within the foot, but in four of five relevant subjects, the sagittal plane motion in the medial arch was greater than that at the tibio-talar joint.”

This and other studies like it prompted Gatt et al (2011) to state that when attempting to measure ankle DF, “the forefoot movement cannot be eliminated completely by placing the foot in any particular posture.” Thus, when validity is so difficult in any test measuring ankle DF, it is my opinion that the weight bearing lunge test is the easiest to implement with the most reliability of any other test. All of that being said, the Australian Physiotherapy Association’s Position Statement on Ankle Injuries still maintains that, “The weight bearing lunge test is a valid test for measuring ankle dorsiflexion range of movement

The last component we need is normative values. Again, that is a difficult question and despite lengthy searches I haven’t come up with much. Bennell found ranges from 5-20 cm in the 13 healthy subjects they recorded, while Konor found a mean of 9.5 cm in the 20 healthy subjects in their study.

Due to the difficulty in finding normative values, I recruited the help of Dr. Craig Payne – a podiatrist and researcher with many publications, a University lecturer and owner of the website RunningResearchJunkie. He states that he typically looks for about 10cm but agrees that there is no established normative database. He stated that they have done some rough trigonometry based on the 10cm standard and came up with a tibial angle of 35-38 degrees.

Recently, I took an SFMA course where they use 5” (12.5 cm) as their pass/fail grade. Generally, I look for around 4-5 inches (10-12.5 cm). I try not to have a black and white line though where a patient with 9 cm is bad, but someone with 10 cm is good. There is certainly a gray area in there.

Finally, soft tissue extensibility from the gastrocnemius cannot be evaluated with the knee bent, so it is advisable to also check ankle DF with the knee straight. I would certainly advise checking ankle DF with the knee straight and knee bent. Both can be done in a weight bearing position. To measure ankle DF with the knee straight, simply perform a standing lunge test with the back leg straight, and measure the back leg’s ankle DF ROM. This will assist in differentiating gastrocnemius tightness from other sources of mobility restrictions.
I don’t have normative values on this. DiGiovanni et al (2002) tried to develop normative values for measuring ankle DF with the knee straight and came up with ≤5° (looking at people with symptomatic feet vs. a healthy control group). There are major caveats to that statement, however. Firstly, they did the test in a non-weight bearing position and with a goniometer. And yes, in their study they measured with more technical equipment, the inter-rater reliability in a regular clinical setting is terrible with both the non-weight bearing position (clinician’s ability to produce torque is questionable) and using a goniometer has poor reliability. Secondly, the reason they came up with ≤5° and not ≤10° is because they were able to accurately diagnose restricted ankle DF in the symptomatic group 76% of the time, whereas if they used ≤10° as a cutoff they were able to diagnose restricted ankle DF 88% of the time in the symptomatic group. They used the lower number because they were able to reliably avoid (in 94% of the cases) unnecessary treatment of those who were not at risk (the asymptomatic group).

Section 2. How Does Reduced Ankle DF Alter Other Lower Extremity Kinematics?

Proposed alterations to lower extremity kinematics include limited knee flexion, increased knee valgus, increased pronation, increased forward trunk lean (on squats), pelvic lordosis and early heel lift. Let’s look at each one individually:

2 i) Limited Knee Flexion:

Imagine lowering your body weight in a squat with ski boots on as I had suggested earlier. We would certainly see less knee flexion occur because the ankle dorsiflexion is limited. Since forward progression of the tibia is limited, more knee flexion would result in a posterior displacement of the body’s center of mass. Since the subject would fall backward at that point, knee flexion becomes limited.

Macrum et al. (2012) found that by having subjects stand on a 12° wedge (heel down) to simulate limited ankle DF ROM and perform a squat. Compared to normal conditions, subjects had a concomitant 15° decrease in knee flexion during the squat, representing a 16% decrease in knee flexion.

Fong et al. (2011) looked at 35 healthy subjects and measured their passive ankle DF ROM. They then had the subjects jump off a 30 cm box and measured lower extremity kinematics and other factors. They found that, “Greater passive ankle-dorsiflexion ROM was associated with greater knee-flexion displacement” In other words, limited ankle DF ROM was associated with reduced knee flexion during landing.

Conversely, DiStefano et al (2008) reported that peak knee flexion angle did not change when wearing an ankle brace to restrict ankle DF ROM during a drop landing test. However, in this study, the brace only restricted peak ankle DF ROM from 22° in the non-braced condition to 21° in the braced condition. Some may question whether limiting ankle DF by 1° is enough to cause measurable kinematic changes in the knee.

Complementing the reduced knee flexion during drop tests or squats is the fact that limited ankle DF is accompanied by knee hyperextension during the stance phase of normal walking gait. This was confirmed by Dudzinski et al (2013). Biomechanically, this makes sense, since forward progression of the tibia over the foot near the end of the stance phase requires ankle DF. If ankle DF ROM is not available, knee hyperextension would reduce the forward progression of the tibia. Therefore, clinicians should routinely check ankle DF ROM is patients with genu recurvatum.

2 ii) Increased knee valgus:

This is one of the more profound alterations in lower extremity kinematics due to limited ankle DF ROM. Not only in terms of implications, but in the amount of research confirming it.

Macrum et al. (2012) was the study listed above that had subjects stand on a 12° wedge (heel down) to simulate limited ankle DF ROM and perform a squat. Compared to normal conditions, subjects had a concomitant 18% increase in knee valgus.

Bell et al. (2012) studied 14 subjects and found that there was increased medial knee displacement during an overhead squat in those with limited ankle DF ROM.

Sigward et al (2008) studied 39 female soccer players and had them step off a 46 cm platform and land with both feet. They found that passive ankle DF ROM measurements negatively correlated with medial knee displacement. In other words, less ankle DF ROM = more medial knee deviation.

Unfortunately, this study like so many others, used a non-weight bearing method of measuring ankle DF with a goniometer. Not only inaccurate, I believe this would produce less of a negative correlation between limited ankle DF and medial knee displacement. The authors even state, “Given the nature of the task, the relationship between ankle range of motion measured on a weight-bearing position may have resulted in a stronger correlation with frontal plane knee excursion.”

Rabin and Kozol (2010) looked at 29 healthy females during a lateral step down test and found that limited ankle DF ROM was correlated with increased knee valgus as visually evaluated by 2 different physical therapists using visual inspection only.

Mauntel et al (2013) had 40 subjects perform a single leg squat and found that those with less passive ankle dorsiflexion also had greater medial knee displacement during the single leg squat. I found this study particularly interesting since the authors also looked at hip adductor and abductor activity during the task. The authors concluded that the hip activation patterns were because of the limited ankle DF.

Conversely, Bell et al (2008) found that during a squat, subjects with medial knee deviation during squat vs. subjects with normal knee frontal plane movement did not have statistically different ankle DF ROM’s. However, there was a trend towards limited ankle DF ROM and medial knee deviation – just not statistically different. The authors state, “Although this difference is not statistically significant, we believe the differences are clinically meaningful
and warrant further investigation
.” In that same study, medial knee deviation was reduced by the use of a heel lift (i.e. reducing the need for ankle DF).

2 iii) Increased Pronation:

The idea of increasing your pronation to compensate for limited ankle DF is not hard to grasp. The video above is an easy way to test it out. Perform that test with the thigh travelling straight ahead and take the measurement. Then do it again, but this time, allow the knee to deviate medially to increase pronation. You will find it much easier to touch the wall. Conversely, try it with a small sock rolled up under the medial longitudinal arch to prevent midfoot pronation. Dorsiflexion will be more restricted in that scenario.

Karas et al (2002) explain it this way, “the DF available distally at the midtarsal joint, in conjunction with pronation, is used to supplement limited talocrural DF. As long as STJ pronation is possible, the midtarsal joint will provide additional functional dorsiflexion range during the progression of stance phase. Body weight will force the ankle foot complex into maximal STJ and midtarsal joint pronation, maximizing midtarsal joint dorsiflexion to supplement talocrural joint dorsiflexion.”

While this makes sense, I have only been able to find one clinical study that measured this distal compensation. Whitting et al (2011) had 48 men perform drop landings after their ankle DF ROM’s had been measured. They found that those with limited ankle DF, “displayed significantly more ankle eversion throughout most of the movement.”

In his book Human Locomotion, Michaud states that if ankle DF is limited, there will be compensatory subtalar and midtarsal pronation. He states, “This action tilts the oblique midtarsal joint axis to a more horizontal position, which allows the forefoot to dorsiflex more effectively about this axis.” This was confirmed in a cadaveric foot model by Blackman (2009) who found that simulated Achilles tendon contracture increased the severity of arch depression and forefoot abduction.

It is interesting to note, however that in a study by Cornwall (1999), they found that the magnitude of rearfoot eversion during walking was not greater in those with ankle DF ROM less than 10 degrees, however there was a delay in the timing of reinversion. However, this study solely looked at rearfoot motion and it appears that much of the compensatory motion associated with limited ankle DF occurs in the midfoot and forefoot.

2 iv) Increased Trunk Lean:

In order to squat with the thighs parallel to the floor, approximately 22° of ankle dorsiflexion is required.

By limiting the forward progression of the tibia over the foot, restricted ankle DF ROM will limit knee flexion and create a posterior shift of the body’s center of mass. This will cause compensatory increased trunk lean in order to prevent the subject from falling backward. In order to increase the forward trunk lean, you need to increase hip flexion. This increases the torque on the hips.

Fry et al (2003) reported this in their study where they limited the forward progression of the tibia by having subjects squat with a board placed vertically from their toes upward (see pic below)

restricted and unrestricted squat

By increasing the forward trunk lean, there was a concomitant increase in hip flexion and so torques were increased at the hip and the low back. The authors concluded that by restricting the forward progression of the tibia, “it is likely that use of greater relative loads for a restricted squat could produce excessive forces at the hips and low back”

In her very popular book “Gait Analysis”, Perry reports that limited ankle dorsiflexion (she calls it excessive plantar flexion, but states that the two terms are interchangeable when discussing gait) will have three main proximal compensations: 1) Early heel lift 2) Knee hyperextension and 3) “Forward lean of the trunk with anterior tilt of the pelvis

Perry - compensations for reduced ankle DF copy

2 v) Increased Ground Reaction Force

Yes, I know I said I was going to list the kinematic variations, and now I’m getting into ground reaction force (GRF). In the next section of the blog, I talk about injuries associated with limited ankle DF and a few of them have to do with increased GRF, so I thought I’d include this.

I don’t think I have to go into a long dissertation about this because biomechanically, it makes sense – if the ankle DF excursion is limited, and knee flexion excursion is limited, you are going to have to absorb landing impact over a shorter distance. In other words, a “stiffer” landing. Therefore, GRF should increase.

This was confirmed in a study by Fong et al (2011) where they found increased ground reaction forces in individuals who had less ankle DF ROM.

2 vi) Impaired Static and Dynamic Balance Testing

Mecagni et al (2000) performed ankle DF ROM testing and then some dynamic and static balance testing. They found significant correlations between reduced ankle DF and poor balance. There was less correlation between ankle DF and static balance than there was with dynamic balance testing and the gait parameters in the POMA balance testing procedures.

There are two studies that have looked at the Star Balance Excursion Test (SBET) – Hoch et al (2012) and Basnet et al (2013). Both found significant associations between reduced ankle DF and SBET test scores. Obviously, the worst scores were for the forward reach test (the weight bearing leg needs a lot of ankle DF ROM to score well) but there were also correlations for the posterolateral test and composite SBET scores.

Section 3. What Injuries are Correlated to Reduced Ankle DF?

The previous chapter has outlined the most commonly documented kinematic changes that occur as a result of limited ankle DF. Those compensatory changes will alter loads and possibly create injury. Here is a list of the most well documented injuries associated with limited ankle DF

3 i) Patellar Tendinopathy

There are two significant studies that have looked at how limited ankle DF can be associated with patellar tendinopathy.

Backman and Danielson (2011) performed a prospective study on 90 junior elite basketball players. They measured a number of potential risk factors for patellar tendinopathy. They found that those with limited ankle DF were at a significantly higher risk of developing patellar tendinopathy. More specifically, if the tibial angle was less than 36.5°, the basketball players had a risk of 18.5% of developing patellar tendinopathy in their dominant limb and 29.4% in their non-dominant limb. Those with a tibial angle of greater than
36.5° had a risk of 1.8% of developing patellar tendinopathy in their dominant limb and 2.1% in their non-dominant limb. So basically, they found there was a 10 fold higher risk (more on this in section 5) of patellar tendinopathy in their ankle DF was limited to a tibial angle of less than 36.5°. This angle corresponds to what Dr. Craig Payne had suggested to me and I had reported earlier in this post.

Mallarias et al (2006) looked at 113 female volleyball players to see the association between patellar tendinopathy and various performance factors including sit and reach flexibility, ankle dorsiflexion range, jump height, ankle plantarflexor strength, years of volleyball competition and activity level. In the end, limit ankle DF was the only factor associated with patellar tendinopathy.

3 ii) Ankle Sprains

Here is the problem with ankle sprains – if you have limited ankle DF, you may be more likely to suffer from ankle sprains. However, one of the biggest manifestations of an ankle sprain is that your ankle DF ROM becomes limited. It’s a bit of a snowballing effect, which may contribute to why recurrence rates are so high

Pope et al (1998) did a prospective study on 1093 army recruits over a 12 week intensive training program. They looked at ankle DF ROM and they tracked only 5 injuries: ankle sprains, stress fractures of the foot or tibia, tibial periostitis, anterior compartment syndrome and Achilles tendonitis. The mean ankle DF ROM was 45 degrees as measured by the weight bearing lunge test. Those with an ankle DF ROM of 34 degrees (the lowest DF ROM group in their study were 2.5 times more likely to suffer from one of those 5 injury types. Some injuries were higher. For example, stress fractures had no correlation, but ankle sprains were 5X higher in those with limited ankle DF. The results showing no correlation to stress fractures is in stark contrast to Hughes (1985) who found a 4.6X increase in metatarsal stress fractures in those with limited ankle DF ROM.

Pope et al – limited ankle DF increases risk of ankle sprains

The reason I listed the paper by Pope is because it was a prospective study. Willems et al (2005) is another example of a prospective study showing that limited ankle DF ROM increases risk of ankle sprains. The relationship between ankle sprains and limited ankle DF has been documented in other research papers that weren’t prospective: Hoch (2012), Yang (2002), Drewes (2009) (measured during jogging)

3 iii) Plantar Fasciitis(osis)

If it is true that limited ankle DF ROM is compensated by a tilt in the midfoot axis of rotation to a more horizontal position in order to gain dorsiflexion from the midfoot, it would make sense that there would be an increase in tensile forces in the plantar fascia. To measure this, we need to put a strain gauge in your plantar fascia. Any volunteers?

Cheung et al (2006) performed a 3D modeling of this idea which confirmed that “Increasing tension on the Achilles tendon is coupled with an increasing strain on the plantar fascia.” This is interesting, but certainly doesn’t prove that limited ankle DF increases risk of plantar fasciitis.

When reading all the “experts” online, you would think that it was a given that there was a strong relationship between limited ankle DF and plantar fasciitis, but it’s not that clear. Rome et al (2001) found no relationship at all, while Irving et al (2007) found in 80 subjects suffering from chronic heel pain compared to 80 healthy subjects, there were more people with excessive ankle DF in the chronic heel pain group compared to the healthy group (33% vs 19%). The mean ankle DF angle for the heel pain group was 45 degrees and 40 for the healthy group.

Those studies are in direct contrast to other studies that have found a relationship between limited ankle DF and plantar fasciitis. For example, using 10° of ankle DF with the knee extended as a cutoff point, Bolivar et al (2013) found that limited ankle DF presented a sensitivity of 100% and specificity of 96% for predicting plantar fasciitis for the participants in this study. Kibler et al (1991) found that ankle DF was limited in 37 of 43 feet affected with plantar fasciitis. Additionally, Patel and DiGiovanni (2011) found that in 254 patients with plantar fasciitis, 83% of them had restricted ankle DF ROM. Riddel et al (2007) looked at 50 patients with plantar fasciitis vs. 100 controls and found, “The risk of plantar fasciitis increases as the range of ankle dorsiflexion decreases.”

3 iv) Miscellaneous Injuries Grouped Together

Trust me , I know this sub-heading has a strange title, but I didn’t know what to call it. There are a number of studies that have found limited ankle DF is associated with higher injury rates in general.

DiGiovanni et al (2002) looked at subjects with “foot symptoms” vs a healthy control group. They found that ankle DF was limited (≤5°) with the knee straight (65% of the symptomatic group vs 24% of the control group) and was also limited (≤10°) with the knee bent (29% of the symptomatic group vs 15% of the control group.
The idea of foot injuries increasing due to limited ankle DF is not a novel idea. Hughes (1985) found soldiers with limited ankle DF were 4.6X more likely to sustain metatarsal stress fractures.

Gabbe et al (2004) had 126 Australian Rules Footballers (community level players) undergo a “battery of musculoskeletal screening tests” at the beginning of the season and tracked who got injured. Restricted ankle DF as measured by the weight bearing lunge test was the ONLY test with a significant association to who got injured. I have been unable to attain the full text, so I don’t know what the ROM cutoff for “normal” was and I don’t know what the other tests in the “battery of musculoskeletal screening tests” were.

Nitz and Choy (2004) measured ankle DF ROM with the weight bearing lunge test on 372 women aged 40-80. They looked at the number of falls over a 12 month period and found that the non-fallers had around 8° more ankle DF than those who fell at least twice. These results were irrespective of age. Also, they found no association between the number of falls and activity level.

Tibrizi et al (2000) looked at the ankle DF ROM on the uninjured side of 82 children with lower extremity injuries and compared the values with a control group of 85 children with upper extremity injuries. They found that there was a significant difference in ankle DF with the knee extended (5.7° vs 12.8° in control group) and also with the knee flexed (11.2° vs 21.5° in control group). Obviously this study has flaws in its research methods, but the authors site other studies that ankle DF ROM is generally equal bilaterally, so they maintain that measuring the uninjured side is valid. They concluded, “Our observations suggest that children with injuries to the ankle have less inherent flexibility before the injury. We believe that this contributes to the cause of the injury.”

3 v) The Rabbit Hole

You take the blue pill, the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill, you stay in Wonderland, and I show you how deep the rabbit hole goes.

Given the number of biomechanical changes that limited ankle DF causes, we can start extrapolating other injuries that theoretically could result. It’s the “If This, Then That” argument. For example…

  1. Non-contact ACL Injuries: Given that limited ankle DF causes a) increased GRF during landing, b) reduced knee flexion during landing and c) knee valgus when landing, can we say limited ankle DF increases your risk of ACL tears? Well, it hasn’t been studied, but those biomechanical conditions that I just listed are well established to be three of the most common risk factors for ACL tears Hewett et al (2005), Yu et al (2006), Griffen et al (2005).
  2. Patellofemoral Pain Syndrome: Given that limited ankle DF causes a) reduced knee flexion during landing and b) knee valgus when landing, can we say limited ankle DF increases your risk of PFPS? Both increased internal femoral rotation and decreased knee flexion during landing were risk factors for PFPS as identified by Boling et al (2009). Knee valgus has been identified as a risk factor for PFPS in a number of other studies including Waryasz (2008). There are some contradictory studies, however they are usually done on subjects currently suffering from PFPS, so the subjects may have been compensating for the pain. In fact, Leitch et al (2012) did look at ankle DF in runners with a history of PFPS (not currently suffering from PFPS) and found reduced ankle DF; however this study was retrospective, so cause-effect is difficult to establish.
    In a recent interview with Lower Extremity Review, researchers Chris Powers and Darin Padua talked about the similarities between ACL injury and PFPS. Powers stated, I wouldn’t be surprised if at some point we figure out that patellofemoral pain is a predictor of who goes on to tear their ACL.”


Section 4. Can Limited Ankle Dorsiflexion be Corrected?

Well… it depends.

A specific intervention may help some people with restricted ankle DF but that same intervention may not help others or even make them worse off. There are many causes of limited ankle DF. It could be a soft tissue extensibility problem (gastrocnemius, soleus or potentially, but rarely tibialis posterior or peroneals), it could be an osseus block from a congenital anomaly, a tight posterior joint capsule/posterior tibiotalar ligament/posterior talofibular ligament, anterior tibiotalar exostosis or from restrictions in the midfoot/forefoot.

When determining whether the cause is soft tissue or joint based, I will leave this up to the clinicians. Obviously some causes are easy to determine (knee flexed vs. straight for gastroc) and other more difficult that require skilled palpation or advanced imaging. When discussing osseous congenital anomalies in his book Human Locomotion, Michaud states, “The most common deformity affecting ankle dorsiflexion is the flattened talar trochlea.” He goes on to states that, “Another bony anomaly that may restrict ankle dorsiflexion relates to a congenitally wide anterior talar dome.

Another possibility for bony restriction could be an anterior ankle impingement exostosis. If you try and force ankle dorsiflexion on a condition like that, you are very likely to create more problems. Alternatively, if there is any osteochondral lesion on the anterior aspect of the talar dome and you try and force dorsiflexion, you are certainly asking for trouble. This is yet another reason why my pet peeve lately is internet “experts” who make blog posts about how to fix or prevent injuries. Without proper examination, sometimes more harm than good is done.

4 i) Increasing Dorsiflexion Following an Ankle Sprain:

Following ankle sprains, restricted ankle DF is a common outcome. It is important to improve the ankle DF ROM because limited ankle DF is a risk factor for future ankle sprains. In a systematic review of the literature by Terada et al (2013), the authors concluded that, “A static-stretching intervention as part of a standardized home exercise program had the strongest effects on ankle dorsiflexion improvement after acute ankle sprains.” That is not to discount the idea of passive, manual mobilizations in the form of Maitland or Mulligan mobilization techniques. The authors acknowledged the idea that, “posterior gliding of the talus may be restricted during dorsiflexion because disruption of the anterior talofibular ligament may induce anterior subluxation and internal rotation of the talus on the mortise and anterior and inferior displacement of the distal fibula.” However, the authors fell short of endorsing manual mobilization techniques and stated, “the clinical relevance of conclusions drawn from the current literature is limited because the associated effect sizes were small to moderate.”

4 ii) Increasing Dorsiflexion in Non-Injured Ankles:

With respect to stretching to increase ankle DF ROM in non-injured adults, it’s a mixed bag.

Radford et al (2006) performed a systematic review of the literature and were able to find 5 RTC’s. They found that there was a benefit to static stretching, although whether the gains seen are clinically significant is questionable. For example, they found that subjects who stretched <15 minutes of resulted in a 2.07° increase whereas 15–30 minutes of stretching resulted in a 3.03° increase and stretching for >30 minutes resulted in a 2.49° increase. Is 3° of gain going to change your kinematics or lessen the risk of injury? We don’t know.

Here is the problem with the Radford study and all others comparing calf stretching: There is no consistency! Radford et al did a fantastic job with what they had, but they’re trying to pool data where some studies had their subjects stretch during weight bearing, others didn’t. Some stretched with the knee straight, others with the knee bent. Some used pulleys and weights to assist in stretching, others didn’t. Some controlled for pronation, others didn’t, some stretched more days a week than others, and some held stretches longer than others. In order to measure gains from the stretching protocols, some studies measured weight bearing, others with goniometers, some with knee straight, others with knee bent….AGH!

Since the Radford paper in 2006, there a couple studies that have emerged: Johnson et al (2007) had 20 elderly women stretch 5 days a week for 6 weeks and found a mean increase in ankle DF ROM of 12.5°. Also, Whitting et al (2011) had 48 men perform drop landings after their ankle DF ROM’s had been measured. There were a number of different interventions in this study and I am not going to attempt to explain them all. Suffice it to say that following 6 weeks of static stretching for 5X 30 second hold stretches for 5 days/week for 6 weeks, ankle DF ROM’s increased 3.1° (7%) with the knee flexed and 5.7° (15%) with the knee extended. The group that stretched not only attained an increase in ankle DF ROM, they also witnessed a decrease in peak Achilles tendon force during their drop landings as well as using a significantly reduced percentage of their peak ankle eversion and ankle DF ROM capacity. They did not, however, reduce their peak GRF. Still the authors concluded that by utilizing static stretching to increase their passive ankle DF ROM, the subjects attained “protective adaptations in terms of the injury potential postulated by the mechanisms observed during pre-intervention baseline
testing.”

Another method used to increase ROM’s is to perform eccentric training on the muscles that cross the joint. This method has been used successfully on the hamstrings (Nelson et al 2004) where eccentric training was shown to work just as well as static stretching over a 6-week program. The posterior calf musculature is no different: Mahieu et al (2008) had their subjects undergo a 6 week eccentric program and found a significant increase in ankle DF ROM. In addition, Whitting et al (2011) also found increases in ankle DF ROM following an eccentric program. Without getting sidetracked too much, this is an appropriate time to talk about ankle DF stiffness, as opposed to ROM. Stiffness is measured via a dynamometer. In both the Whitting and the Mahieu studies, ROM’s were increased, but stiffness was not changed. I am hesitant to advise clinicians to start testing ankle DF stiffness since more equipment is required and in a completely separate paper by Whitting et al (2013) is was found that ankle DF stiffness is poorly correlated to ankle DF ROM.

Yet another method of increasing ankle DF is with night splints, but studies report very poor patient compliance with them, plus you can’t stretch the gastrocnemius without putting the patient in a splint that also travels past the knee to keep it in extension.

Still another method to increase DF is through joint manipulation, Mulligan MWM, Maitland mobilizations. Personally, being an instructor for Active Release Techniques (ART) I’m partial to ART on the posterior tibiotalar and talofibular ligaments. I have found fantastic success with this technique; however I can’t point to any research backing it up. Being a clinician is often a blend of what we have learned from clinical experience and what we learn from reading studies. If RTC’s were our only source of treatment guidance, we’d all be in trouble.

That being said, there are a few studies on manual therapy and increasing ankle DF in non-injured subjects. Some have been negative – Nield et al (1993), Fryer et al (2002). While some have been positive – Vicenzino et al (2001), Dananberg et al (2000), Guo et al (2006). The Guo paper was particularly interesting as not only did they find increases in ankle DF ROM following Mulligan mobilization, but they ROM’s were still significantly different after 2 days of follow up. Additionally, they measured gait parameters and found increases in step length during slow walking and interestingly, increases in velocity. On the other hand, Craib et al (1998) found improved running economy was associated with decreased ankle DF.

As a side note, I have been reading the Twitter world lately and it seems there are a lot of therapists jumping on the “manual therapy does nothing mechanical. Any changes seen are due to descending inhibition and placebo.” bandwagon. For what it’s worth, Collins et al (2004) performed a study on Mulligan mobilization with movement on subjects with subacute ankle sprains and concluded, “Results indicate that the MWM treatment for ankle dorsiflexion has a mechanical rather than hypoalgesic effect in subacute ankle sprains.” I have provided the link to the full text if you care to read it.

Mike Reinhold has provided some great examples on self-mobilization techniques for increasing ankle DF.

4 iii) The Unfixables:

In cases of congenital osseus blocking of dorsiflexion, compensations need to be made. Theoretically the addition of a heel lift will place the ankle in a more plantarflexed position which should add some dorsiflexion excursion to any tasks requiring ankle DF. The changes at the ankle should be seen up the kinetic chain. This technique has been shown to help in the study by Bell et al. (2012) where they found that subjects displaying medial knee deviation during squat also had 20% less ankle DF ROM compared to subjects that did not show medial knee deviation during a squat. By subsequently using a heel lift, subjects reduced medial knee deviation during a squat.

This post has covered both proximal and distal compensations to limited ankle DF. The big distal compensation is pronation to allow greater dorsiflexion distal to the talocrural joint. Remember that Lundgren et al (2008) found that “the sagittal plane motion in the medial arch was greater than that at the tibio-talar joint.” If such compensation takes place and this person goes into a running shoe store, the first thing they’ll hear is “You overpronate, we need to stop that” and the customer will get off the shelf orthotics and/or pronation control shoes. So now, the distal compensation has been reduced, leaving the person’s body with a choice: Add more strain back on to the ankle joint and potentially injure that joint, or compensate further up the kinetic chain. If that person then gets patellar tendinopathy or other knee or hip injury, who’s fault is it? I would argue the person who put them in the device that took away the distal compensation.

Section 5. Is Limited Ankle Dorsiflexion a True Dysfunction?

At the beginning of this post, I referenced another blog post by Dr. Greg Lehman. He writes, “athletes can get by without restricted dorsiflexion in many sports. Do we always want to go changing this? Can you with certainty conclude that a lack of dorsiflexion is a true dysfunction?”

Well I think I can say, after reviewing all of this literature, that limited ankle DF certainly has the capacity to increase knee valgus, decrease knee flexion at the bottom of a drop jump, increase pronation, and change dynamic balance. Ostensibly due to the kinematic changes, the risk of certain injuries increases including patellar tendinopathy, ankle sprains and lower extremity injuries in general. These have been seen in many prospective studies such as Backman and Danielson (2011), Mallarias et al (2006), Pope et al (1998), Willems et al (2005), Gabbe et al (2004). This isn’t including the potential risk factors by extension that I covered in the section “The Rabbit Hole”.

There are very few unconditional and absolute statements anyone can make about healthcare. Just about every answer could start with two words: “it depends”

When we talk about risk, we need to differentiate between absolute risk and relative risk. For example, in the Backman and Danielson (2011) paper, they found that 18.5% of basketball players developed patellar tendinopathy in their dominant limb if their ankle DF was less than 36.5°. If their tibial angle was greater than 36.5°, only 1.8% of them developed patellar tendinopathy in their dominant limb. Therefore, since the risk was 10X more, it is easy to say there is a 10 fold increased risk. However this is only the relative risk. The absolute risk is really only 17 players out of 100 will get patellar tendinopathy because of limited ankle DF.
Alternatively, we could also say
81.5 out of 100 basketball players WILL NOT develop patellar tendinopathy if they have limited ankle DF and 98 out of 100 players WILL NOT develop patellar tendinopathy if they have great ankle DF (read more on absolute vs relative risk here). When you say that 81 out of 100 players with limited ankle DF won’t develop patellar tendinopathy, that doesn’t sound too bad!

This plays into the statement “athletes can get by without restricted dorsiflexion in many sports.” This is absolutely true. However, risk is risk and if I can reduce the risk of getting injured in my patients, I will certainly tell them. Let’s get into the world of analogies: Imagine some guy, Joe, likes to go to a bar every night. Let’s say he has a 20% chance of getting in accident when he drives home from the bar if he’s been drinking. Conversely, he has a 2% chance of getting in an accident if he doesn’t drink. In other words, a 10X increase of getting in an accident if he drinks. However, if he drinks before he drives, 8 out of 10 times he’s OK. One day, he comes to you and asks why he got in an accident (aka patellar tendinopathy). Do you tell him not to drink and drive (aka increase his ankle DF)? I would argue that I would try and get him to stop despite the fact that 8 out of every 10 times he was OK.

Similarly, not all athletes with limited ankle DF will have an injury because of it, but I wouldn’t want to be playing sports or be a runner with increased risk of injury. Some people discount the idea of movement assessments, but ankle DF is one movement assessment I will continue to utilize on most patients and if it is significantly limited I will suggest that they try and correct the dysfunction.

Unfortunately, with the lack of consistency in the research of what “limited” ankle DF is defined as and how to measure it, we can’t make blanket statements. In addition, due to the many causes of limited ankle DF, the success of attempting to restore mobility can vary greatly. Still, I believe that we have enough data to say that limited ankle DF causes biomechanical compensations and increases the risk for various injuries.

 

 

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Non-Clinician's Guide to Ankle Dorsiflexion

This blog post is regarding limited ankle dorsiflexion – the biomechanical implications, the injuries that may result, how to test it and what to do about it. This is the “non-clinician’s” version. If you are a clinician, or want to read the references behind anything I have said below, please click here to be brought to the “clinician’s version”. Mind you, the clinician’s version is very detailed and lengthy with many, many references.

If you are still reading up to this point, I am assuming you are not a clinician/biomechanist/healthcare provider..

What is Ankle Dorsiflexion?

Ankle Dorsiflexion is the action of closing the angle between the front of the shin and the top of the foot. This could be done in a couple ways:

1) If the foot isn’t fixed to the ground, ankle dorsiflexion is the action bending the ankle in a way that brings the toes and foot upward toward the shin bone

Ankle DF with the foot moving

2) If the foot is fixed on the ground, ankle dorsiflexion is the action of the knee and shin travelling forward over the foot.

Ankle DF with the foot fixed to the ground

What Happens when Ankle Dorsiflexion is Limited?

We all need to have a certain amount of mobility in ankle dorsiflexion (DF) in order to run, walk, go up or down stairs, squat, get up out of a chair etc. Imagine trying to do those tasks while wearing a ski boot and you can get an idea why ankle DF is so important.

Limitation in ankle DF range of motion has been shown to cause many compensations. For example, a poor mobility in ankle DF has been shown to cause the arch of the foot to flatten and the foot to roll inward (pronation). This is because it is thought that we can get as much DF from the bones of the foot as we can from the ankle itself. Limit the dorsiflexion in the ankle and we try to compensate by adding dorsiflexion motion to the foot. Further up the leg, limited ankle DF causes limitations in knee bending and also, the knee can collapse inward.

Imagine trying to squat with limited ankle DF. If your knees can’t travel forward over the toes because the ankle is stiff, your center of gravity will shift backward. In order to compensate, people tend to bend their trunk forward more so they can shift their body weight back over their center of support – their feet. Bending the trunk forward more can put more load on the low back.

Can Limited Ankle Dorsiflexion Cause Injury?

These compensations listed above have been shown in biomechanics laboratories around the world. Unfortunately, our bodies pay a price for these compensations. Prospective studies show that people with limited ankle DF suffer from more knee injuries, foot and ankle injuries and just more injuries in general. A prospective study is where you perform some test on a group of people at the start of the study and then follow them for a given period of time. For example, it was recently shown that basketball players who have limited ankle DF sustained up to 10X more incidents of patellar tendonitis (a type of knee pain) that those players who had adequate ankle DF at the beginning of the season.

How Do I Know if I Have Limited Ankle Dorsiflexion?

There is a relatively simple way to test your ankles to see if you have adequate ankle DF range of motion. It is called the weight bearing lunge test. The test is contained in the video below. You should be able to get your knee forward of your toes by approximately 10cm (4 inches)

[vimeo]https://vimeo.com/73530410[/vimeo]

What Can I Do If My Ankle Dorsiflexion is Limited?

Now we come to the really difficult issue. Often times, increasing your ankle DF range of motion can be as simple as a regular routine of calf/ankle stretching. However, when it comes to the question of “what can I do about it“, the real answer is…”it depends.”

There are a tremendous number of reasons you may have limited ankle DF. Some may be soft tissue based (tight muscles and tendons) that you can stretch your way out of, but often times, the limitation is within the joint – maybe a type of arthritic condition, maybe the shape of the bones is just the way you grew, maybe there is some damage in the cartilage…it’s tough to tell unless you know what you’re looking for.

If you have limited mobility and have gotten the ankle looked at by a qualified health professional (I would really recommend someone who knows ankles – not just a general healthcare provider), you may want to try therapy from a physical therapist or chiropractor. There are also some self-mobilization procedures you can do. Mike Reinhold has provided some great examples on self-mobilization techniques for increasing ankle DF.

As always, please consult with your healthcare provider before undertaking any of these porcedures.

The Great Shoe Pendulum

Part I – Minimalist Shoes Get a Thick Skin

Pendulums tend to swing back and forth and when you reach one extreme, you can be sure that it will head the other way. The running shoe industry is no different.

The 1990’s and early 2000’s saw a gradual move to heavy, bulky shoes with elevated heels and pronation control out the wazoo. This big, stiff shoe trend was reversed in the mid to late 2000’s through a variety of sources including the book “Born to Run”, research by Lieberman and others. Studies found that stability shoes increase joint forces at the knee, hip and ankle as well as research reviews that found there is no good evidence that elevated heels, cushioning or pronation control reduce injury and that the link between pronation and injury is tenuous at best. The minimalist movement was underway. By ditching the big, stiff, bulky shoes, it was suggested that the lower joint torques would reduce injury. This has been largely unproven, but not dis-proven either. More likely, by switching to a more minimalist running shoe, you are moving joint loads around from one joint to another. There is no doubt that most people run differently when barefoot compared to wearing cushioned, elevated heel, pronation control running shoes. Some people may experience lower rates of injury, some may not, some may become more injured.

Personally, through all the research I’ve read and the 1,000+ patients that I’ve done gait analysis and rehab on, I can state that I feel barefoot running and minimalist shoe running play a significant role in helping runners correct certain gait patterns. This makes barefoot running and minimalist shoe running a great tool to use for running.

So, more and more people bought Vibram Five Fingers and other barefoot style shoes. Predictably, some people loved them and became zealots and others tried them and didn’t like them. Possibly the biggest complaint about barefoot style shoes is that it doesn’t feel very good on the feet. You feel much more impact due to the lack of cushioning – what the barefoot proponents euphemistically refer to as “feedback”. Ironically, it is thought that the changes in form seen with barefoot running is because you feel more impact and so you moderate your running style. For the most part, this should be of benefit to your form. However, training many miles whilst feeling the full effect of every footstrike is unrealistic for many people.

Well, here comes the pendulum. We are about to witness the advent of “maximalist” running shoes. Not in the way that it was in the 90’s and 2000’s, with the pronation control and the elevated heels and stiff, heavy shoes. Instead, the new maximalist era appears to be staying with the low drop, lightweight flexible shoes, but with the addition of maximal cushioning. Enter the era of Hokas, New Balance Fresh Foam 980’s, Altra Olympus and other Uber-Soft, plush rides that manufacturers are making lightweight (relatively), low drop and flexible.

Hoka can certainly be credited with initiating this style of shoe. Just like what happened in the minimalist movement, the big shoe makers (Brooks, New Balance, Adidas etc.) are likely to follow. I have heard through different sources that up to a third of the ultramarathoners are wearing Hoka’s at some races (depending on the terrain). Whether or not this “maximalism” trend will become as big as “minimalism” was (or still is…see below for more info on that) is yet to be seen, but it is apparent that it is starting to get a foothold on the upcoming shoe market.

Part II – The Fad is Over…Or is it?

It has been reported that the minimalism trend is over, and the pendulum is swinging back the other way. According to SportsOneSource, “Sales of Minimal/Barefoot Running Footwear, net of Nike Free, declined by nearly 30 percent and were only 4 percent of all running shoes sold. Sales of Nike Free gained more than one-third.”

That statement made headlines and so people naturally thought that minimalism was dead. In fact, the original article from SportsOneSource reported “the fad is pretty much over”. However, they eliminated the Nike Free from the equation. Although they classify the Nike Free as a minimalist shoe, they felt that it is purchased more by active people, not just runners.

Unfortunately, SportsOneSource also did not include running specialty stores. Leisure Trends Group does include those stores. Pete, over at RunBlogger posted an article back in June where he went through the last 16 months of data from LTG. This is what he found: (green means increased dollar sales, red means decreased relative to that month in the previous year; darker colors indicate double-digit change):

LTG-Shoe-Sales_thumb3

Pete states, “If anything, minimal did better in terms of relative growth compared to more traditional categories in Dec 2012-Mar 2103…growth of minimal as a category has slowed, but has not declined.”

However, this begs the question, “What is minimalism?” Is it a low heel-forefoot angle? Is it lightweight? Is it a wider toebox? Is is minimal cushioning? Is it no pronation control devices? Is it a combination of all those? It is difficult to quantify what a minimal shoe is, and if you can’t quantify what it is, how can you track it’s sales?


Even if “the fad is over”, which is questionable, there are a lot of positive things that came out of the minimalism movement. For example – many people started thinking about their running form, the idea of prescribing footwear based on foot type is quickly losing credibility, toe boxes are being made wider, most shoe makers are lowering the heel-to-forefoot angle on their shoes (Saucony went as far as to make their lineup of shoes with no more than an 8mm drop).

If the barefoot/minimalist trend is fading, again I would assert that it did the running community a huge favor by getting people to think about their form and get away from relying on a plastic insert in a shoe to end your running injuries.

In the end, I would assert that no matter what shoe you’re in, if you have poor training (too fast, too often and ramp up too quickly) or if your form or running style is poor, you will get injured no matter what shoe you’re in. In the September issue of Men’s Health, Dr. Mark Cucuzzella probably worded it best when he said, “The bottom line is, running causes running injuries. Not shoes, not barefoot. Running. If you don’t want a running injury, don’t run.