Sobering Video and Report

This past weekend I was attending a Faulty Movement Patterns seminar by Dr. Craig Liebenson when I was introduced to this video below and the website Designed to Move. Before you read any further, I would suggest you watch the video in it’s entirety.



With 9 & 11 y.o. boys of our own, this video struck home. Thankfully, they both play lacrosse, do a lot of running and triathlons. However, the video is sobering. The advent of antibiotics, hygiene, food supply and nutrition has gradually increased out lifespan and quality of life…until this generation.

On the website, you can scroll down on the main page and find out loads of info. If you really want to get into it, the website’s full report is found here. They have done a good job of literature referencing in that report.

In it’s entirety, the problem goes well beyond just the lifespan of physically inactive children. As the pictures below indicate, there is also a financial impact and a significant loss of quality of life. Please click on each picture to see the financial, educational and other consequences of physical inactivity.


1) Encourage children to partake in a variety of physical activities. Variety is probably just as important as quantity.

2) Lead by example. Kids learn by exposure.  You don’t have to do an Ironman, but you should be doing something!

3) Make it fun for them. If they don’t enjoy it, they won’t do it. If it’s boring, they won’t want to do it. Find out what their friends participate in and see if they would like to as well. They will be able to spend time with their friends and car pooling to get to an organized sport helps everyone.

The tone or message of this entire post should not be anything new to anyone reading. However, the way the message is delivered hopefully is. I say hopefully because SOMETHING eventually has to sink in. Anecdotally, I see more sitting and inactivity in the past 10 years and attribute it to the advent of laptops, smartphones and tablets.  I may be wrong, but I don’t think so


The Definitive Guide to Pronation – Patient Version

Pronation. It has been the foundation for prescribing and selecting running shoes for decades and ‘over’pronation has been purported “cause” of a dizzying array of running injuries. Overpronation to runners is what global warming is to Al Gore. It’s going to kill us all. But does the evidence really back it up?

The impetus for this article was because of what I read. The barefoot and minimalist advocates say there isn’t anything to pronation, while the shoe companies, stores and podiatrists imply it’s the bane of all running injuries. Yet, if you ask any of them to define “pronation”, you will get wildly different answers. Want to have some fun? Ask them when at what point pronation becomes “over”pronation. If they think they know the answer, they are apparently smarter than any top biomechanist researcher in the world. Not even they have figured that one out yet. So, What is a runner (or a clinician) to believe? The only way to find out is to delve into the research yourself headfirst and see what you come up with.

So, that’s what I did. I started with what was supposed to be a one or two page report on the validity on ‘over’pronation, but one month later, I emerged out the other side with a 9,000 word, 18 page paper with 55 literature references. It turned out way more technical than I had intended and now is really just for clinicians or other people who are REALLY interested in foot mechanics. A sort of magnum opus. You can find it here. It’s kind of technical, but if you really want to know your stuff, well, there it is. If you don’t want the lengthy technical version, stay on this page and read below the orange button.

Alternatively, on this page, you will find the executive summary. A much more palatable summary intended for everyone. What I say below is not off the cuff and without doing my research. If you don’t like what I have to say, it’s all backed up with references in the “Guide for Clinicians”
So enough with the hype, here you go…

Topic #1 – What is Pronation and Overpronation?
When weight bearing, pronation is what happens when the arch of the foot flattens a bit and also facilitates some inward rotation of the ankle and shin. When walking or running, our feet are supposed to pronate. This is normal!
How much we are supposed to pronate, the velocity of pronation, how long we are supposed to stay in pronation and how much the pronation actually influences the inward rotation of the tibia is debatable. Not because it hasn’t been studied. It has been studied in great detail. It’s just that the studies are inconsistent and conflicting
Thus, we can’t agree on what pronation exactly is defined as. This makes “over”pronation even more difficult to define

Topic #2 – Does ‘Over’pronation Cause Injury?
The influence of pronation on injury has been broadly and exceedingly exaggerated. There is too much emphasis placed upon pronation and injury so it needs to stop. Studies that show ‘over’pronation (which is exceedingly ambiguous and undefined at this point) are associated with injury are mostly done on measuring subjects feet in a non-weight bearing state which don’t correlate well with actual running or walking. Those studies that measure pronation when actually walking or running are very conflicting and inconsistent when associating ‘over’pronation to injury. In addition to being conflicting, the studies that link pronation and injury merely imply association – not cause.
Is there an association? Yes, for some people, but not nearly as much as the general public is lead to believe.

Topic #3 – Why all the Inconsistency in Research?
There are a few different answers to this, but I’ll focus on two of them:

a) Research methods are not consistent. Some researchers measure pronation by using markers on the shoe (your foot slides in the shoe when you walk or run, so not very accurate) some place markers on the skin (your bones slide in your skin, so some accuracy lost there too) some place pins in the bones of the subjects (study sizes are small – who wants pins stuck in their bones?) Some research uses cadaver feet, some use elite runners, some use novice runners. Get the point? If research methods are inconsistent, how can you expect results to be consistent?

b) This is probably the biggest idea I want people to get out of this paper: It appears as if control of the leg when running is from the top down, not the bottom up. In other words, the leg controls the foot, the foot doesn’t control the leg. That means that if you are going to put some orthotics in the shoes to “control” the situation, but the real “control” is coming from the lower leg muscles or the hip, you’re fighting a losing battle. Pronation research has mainly looked at the movement of the foot and the lower leg to try and see patterns, but if the control is coming from higher up, you will have inconsistency. If you don’t believe me, look at the “clinician’s guide”. It’s all laid out there.
No wonder why orthotics and shoes show a conflicting ability to control the foot and shin.

Topic #4 – What Should I Do?

a) When choosing a shoe, go with what has worked for you in the past. Don’t be lured into a shoe based on what someone tells you you need because they can “see” you ‘over’pronate. Go with what feels right and comfortable for you and if it doesn’t work, try something different. Trial and error will work it out.

b) If you are still getting injured, get a full body gait analysis and look into the credentials of the person looking at your form. Do they know anatomy and mechanics, or did they read “chi running”. No, this statement isn’t based on research reviewed in this paper, but since the research suggests that the mechanics are “top-down”, you need to look into the stability and mobility of the hips, pelvis and core. You may have some hip or pelvic mechanics that need changing.

c) If you have tried a variety of shoes, tried the gait analysis, modified your training habits and are still getting injured, you may want to try orthotics. However, it appears off the shelf orthotics are just as beneficial (and 1/5 the price) as custom made, casted orthotics, so save your money when thinking about the $500 custom orthotics.

In the end, there is only one blanket statement we can make – anatomy and biomechanics are highly variable between people. It’s not about “minimalism is great”, or “overpronation is bad”, it’s about being an individual. Don’t try and force yourself into a shoe or some running style that some guy wrote about on his blog

Ok, now that I’ve offended barefoot and minimalists, podiatrists and “Chi Runners”, I think I’ll end it there. I’d love to hear any feedback – hate mail or otherwise.

Hamstring Strains and Pelvic Positioning During Running

I have seen a string of hamstrings pains in runners lately, so I thought I would make a post regarding how faulty running mechanics can increase the risk of hamstring strains.

Keep in mind that the hamstrings are under the greatest tension at approximately the point of terminal swing, or a fraction of a second before the leg hits the ground [1,2,]. Also keep in mind that lack of hamstring flexibility has not been shown to be a risk factor [3,4].

The bulk of this post is in the video below, so please watch it. There is a point to the video and that is, if I told you that a “delayed swing leg, weak abdominals or restriction in the anterior of the femoracetabular hip capsule on the train leg causes the ischial tuberosity to move posterior via an anterior pelvic tilt which increases hamstring tension in the leading leg”….it would get confusing. Instead, just watch the video – it’s easier to understand.

Running mechanics are so important, as pointed out in this recent 2013 study published in the British Journal of Sports Medicine. They followed a 26 y.o. footballer (aka “soccer player”) who had no less than 5 hamstrings strains in one season that kept taking him out of action. He had 4 MRI’s and lots of therapy on the hamstring. It wasn’t until they took a comprehensive approach – looking at his biomechanics, going through a lot of abdominal stabilization training and other factors that he returned to the sport without the hamstring tearing again. Lesson to be learned: treating the injured hamstring in isolation from the rest of the body did nothing!


1 Heiderscheit et al., Identifying the time of occurrence of a hamstring strain injury during treadmill running: a case study. Clinical Biomechanics 20 (2005) 1072–1078
2 Thelen, D.G., Chumanov, E.S., Hoerth, D.M., Best, T.M., Swanson, S.C., Li, L., Young, M., Heiderscheit, B.C., 2005. Hamstring muscle kinematics during treadmill sprinting. Med. Sci. Sports Exerc. 37, 108–114.
3 Gabbe BJ, Bennell KL, Finch CF, Wajswelner H, and Orchard JW, Predictors of hamstring injury at the elite level of Australian football. Scand J Med Sci Sports 16: 7–13, 2006.
4 Gabbe BJ, Finch CF, Bennell KL, and Wajswelner H. Risk factors for hamstring injuries in community level Australian football. Br J Sports Med 39: 106–110, 2005.

Forward Lean, Knee Pain & Lever Arms (and a bit of cynicism at the end)

If you’ve ever read some of my other blog posts, you would know that I loathe the prescription of “make sure you lean forward when you run” promoted by all the “one size fits all” proprietary running techniques out there (Pose, Evolution, Chi etc)

I firmly believe that running technique is uniquely individual, as demonstrated by the following post…

While I can’t stand the often promoted “forward lean” instructions for running, there is a time and place for it. For example, when a runner is suffering from knee pain – more specifically, patellofemoral pain syndrome (PFPS), a forward maybe justified…but not necessarily. This post gets a bit detailed at times. If you get confused, consult this video – it may help explain.

There are many factors to consider when a runner is suffering from knee pain (more specifically, “PatelloFemoral Pain Pyndrome – PFPS). One of the biggest factors is the stability of the hip in the transverse plane (i.e internal vs. external rotation). However, I plan on making a post on that at a different time

Anyway, I digress…

The point of this article was to talk about PFPS and the “forward lean”. One of the many factors to be considered is trunk position. Recent research has shown that an increased trunk flexion angle angle (bending forward) can be associated with a decrease in knee extensor moment which results in less compressive force on the patellofemoral joint (a joint in the knee). Keep in mind, the forward lean reduces the extensor moment, but doesn’t change the knee flexion angle. (For those about to get mad at me for using “bending” forward and “leaning” forward interchangeably, I find that most people who are told to “lean” forward end up “bending” forward anyway. More on that later…)

So, why does bending/leaning forward reduce the strain on the patellofemoral joint?

Well, very briefly…there are two competing ground reaction forces that are contributing to the external flexion moment at the knee (a force causing it to bend): 1) the vertical ground reaction force and 2) the anterior to posterior ground reaction forces. Essentially, when you land, there is a vertical force being applied to the knee because your body is going downward when you land, and there is also a posterior force being applied because you are also going forward when you land. The quadriceps exert an extension moment in order to combat the two external flexion moments that are being applied. Hopefully, they sort of cancel out and the knee doesn’t buckle.

Unfortunately, the extensor moment at the knee that is exerted by the quads also puts a large load on the patellofemoral joint.

In order to reduce the extension moment on the knee from the quadriceps you need to move the load somewhere else. In this case, by bending the trunk forward, you move the center of mass more forward (closer to the knee), thus reducing the moment arm for the body’s center of mass force on the knee. In this case, you move the load from the knee on to the hip and low back. See figure 1 below


Forward lean and lever arms

Before we get any further, if you don’t know what a lever arm is, please look at figure 2 here…


Lever Arm Explained

So, here’s the caveat. If the objective is to reduce the moment arm for the body weight to the knee, is leaning forward the best strategy? Well, maybe for some, but certainly not for everyone.

As you can see in figure 1, the lever arm for the knee is reduced by leaning forward, however, the lever arm for the hip and the low back muscles is increased, thus increasing the load for the glutes and the low back muscles. Unfortunately, this is not mentioned in a couple studies that found reduced load on the knee by leaning forward.

It’s a trade-off.

I have included this video to help explain thing – perhaps if is more clear on a video…

Next time someone tells you that you should “lean forward”, please explain all this to them, or refer them to this blog. If you want to reduce the lever arm from the cernter of mass of the body to the knee, another strategy would be to not overstride. Landing with the foot closer to the center of mass, I think, may be a better strategy.

In the end, there are various ways of dealing with injuries and performance. If you think that getting a gait analysis from just anyone is a good idea, you may be in for a surprise. Can they explain joint moments, lever arms, and force vectors? Do they understand detailed anatomy and the functional aspects of it? Do they read research, or do they read blogs? Do they have a “one size fits all” approach?

Sorry if I seem harsh, but I’m getting tired of clients telling me they’ve gotten a gait analysis done, only to find out it was from a source who knows nothing about anatomy, or biomechanics, but they are a “good runner”. I hope you don’t take your broken car to someone who is a “good driver”, but knows nothing about how a car operates.



Stability from the Ground up

The inability to control the stability of the foot has paramount implications on the rest of the leg and whole body posture. I may be biased here, but this is a must read for anyone with feet.

One major tool in the development of stability in the lower leg is the “Short Foot Exercise (SFE). (what do they say about people with short feet?)

Why is the SFE important? Very briefly, when you run your ground contact time is somewhere around 1/5th of a second. In that brief period of time, your foot has to provide a stable base of support for balance and propulsion while also being mobile enough to be a major shock absorber for the body. A fault in strength, timing or coordination of the muscles will quickly result in poor performance and/or injury.

Last year, I wrote an article on the SFE, but more recently, a study was just published in the Journal of Sports Rehabilitation and looked at the ability of the SFE to improve balance in both static and dynamic situations.
The study wanted to find out: when it comes to foot conditioning to increase arch height as well as improve balance in static and dynamic tests, which is better – the SFE or the traditional “towel-curl” exercise (TCE). Personally, I’ve never given the TCE to any patients because I don’t feel it’s very functional. As it turns out, in this new study, I was right…sort of.

The study was 4 weeks long and had the subjects perform either the TCE or SFE 100 times per day. Then they measured
1) the height of the navicular bone during weight bearing (basically, the height of the medial longitudinal foot arch),
2) the total range of movement of the center of pressure (COP) in the mediolateral (ML) direction for a static-balance test and
3) the amount of COP movement in a dynamic-balance test
(Y-balance test).
The center of pressure was measured via forceplate.

In the end, there were no differences in the height of the navicular bone or differences in the static balance test. All groups showed an improvement in reducing the movement of the COP in the ML direction (improved stability) for the dominant leg, but the SFE group showed a much greater improvement in the non-dominant leg – an average decrease of 9.3 mm in the movement of the COP in the ML direction.

So here’s the gist:
• Foot stability and mobility are important aspects of performance and injury prevention for everyone
• Studies suggest (like this one, this one and this one) that wearing shoes can reduce the strength of the muscles that control foot stability (no, I’m not suggesting we all go barefoot)
• So, it would seem important to do some conditioning on the foot muscles
• The “short-foot” exercise seems like an important tool in that foot conditioning

“So, is that it? All I have to do is the SFE to have good foot health?” No, obviously not. However, I’d suggest it’s a good place to start. After you’ve mastered the ability to perform the SFE (practice it while sitting at your computer, eating, watching TV or whatever) you should progress. Here’s a standard progression we use in the clinic:
Learn the SFE while seated -> Progress to doing the SFE while standing -> then when doing Vele’s Forward Lean, -> then standing on one leg, -> then one one leg doing a sideways medball toss, one arm cable rows etc.

By now, you should have developed new motor control programs that are relatively unconscious.
Patients usually take a while to gradually develop proper stability during this progression.  I think for many people, this is an important tool for injury prevention and I use it frequently for patients with a history of injury and poor stability.

The "One Leg is Shorter" Excuse

Before reading this, realize it’s lengthy and somewhat detailed. Either get comfy, or come back and read it later. If you’ve ever been told you have “one leg shorter”, this article is for you. If you have a friend who’s been told they have one leg shorter, forward this on to them…

Both in private practice and in working with the Rev3 triathlon series across the country, I treat hundreds of pro and age group triathletes. In doing so, I hear so many stories of anguish and despair as the athletes recount their history of injuries and what they’ve done to try and remedy the problem. This is the part when I get frustrated, because many, if not most of their previous treatments are questionable at best, but downright irresponsible when they tell me what they were prescribed by their health care provider.

I could make this into a small book if I were to get into the cortisone injections, the colorful self adhesive stretchy taping and the over abundance of stretching an injured muscle, but this post will strictly be about a pet peeve of mine – the “one leg is shorter than the other” excuse. (from here on out, I will refer to a Leg Length Inequality as “LLI”)

The post will be in 4 sections:

  1. How was your LLI determined? (methods are important)
  2. Is the leg really shorter or, does it just appear that way? (functional vs. anatomic)
  3. Is your LLI even relevant? (size IS important…)
  4. What should you do about it? (Can the treatment cause more problems?)

1) Functional vs. Anatomical Differences

Anatomic LLI denotes an actual difference in the length of the femur, tibia, talus or calcaneus, which are the weight bearing bones of the leg. Functional LLI is referencing a difference in the apparent length but is caused by biomechanical issues in the kinetic chain such as pelvic rotation, excessive foot pronation, knee valgus (knee deviating inward), muscle contractures etc.

Trying to correct a functional LLI with a shoe insert (heel lift) is silly, and not addressing the real problem. In his book, Michaud correctly states “a heel lift should never be used to treat a functional limb length discrepancy because the lift does not address the cause of the discrepancy and may even create a unilateral weakness of the involved lower extremity” [1]

2) How was your LLI determined?

If we want to have a discussion on LLI, we have to realize that the way the vast majority of people are diagnosed is by laying on a table and having a clinician look at their legs with a visual inspection. Unfortunately, this is a very unreliable way of looking at things as there are many factors that can cause one leg to “appear” shorter, including pelvic obliquity, suprapelvic hypertonicity (muscle tone in the low back pulling asymmetrically on the pelvis) etc. Many studies have shown that this method is unreliable. For example, Rhodes et al., demonstrated that the side and magnitude of “short legs” were not significantly correlated with radiographic anatomic LLI, indicating they are separate phenomena [2].

In another study, 45 patients were examined via this method by 2 clinicians. All (100%) of patients were determined to have a leg length discrepancy (Yes, you read that correctly – 100%). Also, there was “poor reliability when determining the precise amount of that leg length difference.” In addition, the study noted “There does not appear to be any correlation between the side of pain noted by the patient and the side of the short leg as observed by the clinicians” [3]

Many therapists will say that they are more accurate because they measure the leg length by using a tape measure to go from a point on the pelvis to a point on the ankle. Again, this doesn’t account for functional differences between sides. One study summarized this nicely by stating, “Tape measure methods for measuring LLI have been found to be of equivocal accuracy and may be less accurate than radiological criterion standard method for assessing anatomical LLI” [4]

OK, so doing a visual examination isn’t reliable, using a tape measure isn’t reliable, what’s left? One purportedly reliable method is done with a standing x-ray of the pelvis and measuring the levels of the femoral heads. This method was developed by Friberg and even he states that it is unreliable, “The method described here is not meant to substitute the methods for measuring accurately the length of the different parts of the lower extremity” [5]

Essentially, it is unreliable because it fails to account for other functional factors. (For example, I take and X-ray of your pelvis so I can see the height of each femoral head. Is there is a difference in the length of the bones, or is it because there is more pronation on one side which is causing that leg to “appear” shorter?)
Another article pointed out that, “methods that incorporate both anatomical and functional LLI without distinction (eg, Friberg method) necessarily overestimate the incidence of anatomical LLI compared with a stricter definition.” [6]

So what is the stricter definition? The only way to reliably determine an anatomic LLI is to take x-rays of the lower extremities and actually measure the length of the femur, tibia, talus and calcaneus, since these are the primary weight bearing bones. However…even when that is done (usually laying down), it doesn’t account for the other aspects of biomechanics which occur when standing, running or walking. For example, if I have 7mm LLI when x-rayed laying down, maybe I also run with more knee valgus on that side which would negate the anatomic difference. It is an inexact science at best!

3) Is your LLI even relevant?

Let’s pretend that you’re healthcare provider is “positive” there is a LLI. They want you to wear a heel lift to compensate for your 12 mm short leg… Is 12mm (1/2 inch) a lot? Is 6mm (1/4 inch) a lot? what about 19mm (3/4 inch)? Well, we have some clues…

Studies show that 90% of the population has LLI [7]. We know that LLI of >20 mm (>3/4 inch) affects only approx. 1/1000 people. [8].
So, if LLI is so common, and 999/1000 people don’t have LLI greater than 20mm, how big does LLI have to be before it becomes “clinically relevant”. In other words, how big does LLI have to be before it causes either gait compensations or pain/injury? Again, we have some clues…

One study found that in 74 adults, there were no functional or cosmetic problems if the LLI was less than 20 mm (3/4 inch). [9] Another study, looking at 35 marathon runners, found “discrepancies of 5 to 25 mm are not necessarily a functional detriment to marathon runners, and no consistent benefits could be attributed to the use of a lift.” [10] Again, another study used data from force plates to look at how compensations for LLI happened. They found a threshold discrepancy of 3.7% (approx 20mm on average) of the limb length before an asymmetrical gait occurred [11]. Yet another study examining gait on 35 children found “discrepancies of less than 3% of the length of the long extremity were not associated with compensatory strategies.” [12]

So, these studies show that gait compensations usually do not occur in subjects with LLI less than 20mm (3/4 inch), or less than 3% of the limb length. Since 999/1000 people don’t have LLI >20mm, and gait compensations and ground reaction forces aren’t different with anything less than 20 mm, why all the hype? In other words, in a typical triathlon of 3000 people, there are only 3 people with a LLI >20mm. My own anecdotal experience [13] in my clinic and working on hundreds and hundreds of athletes at triathlons across the country tells me there are a heck of a lot more people than that who have been “told” they have LLI.

4) What should you do about it?

So, we’ve examined the unreliability in determining LLI, we’ve looked at functional vs. anatomic LLI and realized that anything less than 20mm difference should probably be left alone (exceptions exist, such as acquired LLI. For example, people who have a shorter leg due to a femoral fracture).

So now, what do we do if there truly is LLI that needs to be compensated for?
As you may have already guessed, there is even disagreement as to how to deal with the LLI if one is found. In his textbook, Michaud states that placing a heel lift under the calcaneus will result in 33% less of a change in the total compensated height, since the talus is 1/3 of the way between the calcaneus and the metatarsal heads. For example, a 6mm lift under the calcaneus will result in raising the talus 4mm [14]

In addition, only using a heel lift ends up causing “altered motion and/or transfer weight to the medial forefoot.” Essentially, this then means that your are altering the biomechanical stresses applied to the foot, raising the potential for foot pain/injury by altering it’s normal function.
To compensate for this, many clinicians recommend a full-length insole, rather than just a heel lift. I don’t think I need to say it, but I will…this will still result in altered biomechanics of the foot, and again, raise the potential for foot pain and injury.

However, this also brings up another point. If there is pain somewhere, and the LLI excuse is used without properly addressing the real problem, more problems can result. Rather than disclosing names, I can tell you of one pro triathlete this year who played around with inserts after she was told she had one leg longer. She missed most of the season because she was battling pain. At a Rev3 race, she came to see me. It really wasn’t a long diagnostic process to realize that she had an internal hip pathology and needed surgery. She went back home, consulted with a good surgeon who agreed that there was a significant internal hip pathology and she has since had the appropriate surgery. Could the whole thing have been avoided with proper earlier diagnosis?

Please keep in mind, this article is not intended to deny that LLI exists, doesn’t cause pain and suffering, or should never be treated. My problem is that it is over-diagnosed without proper thought or investigation, not diagnosed properly and usually managed poorly. Until healthcare providers actually take the time to THINK and critically analyze runners in a thorough and step by step process, quick and easy solutions will prevail…such as cortisone injections, stretchy colorful taping and heel lifts.


1) Michaud, Thomas, DC. Human Locomotion: The Conservative Management of Gait-Related Disorders. Newton, Massachusetts: Newton Biomechanics. 2011. Pg. 189
2) Rhodes DW, Mansfield ER, Bishop PA, Smith JF. Comparison of leg length inequality measurement methods as estimators of the femur head height difference on standing X-ray. J Manipulative Physiol Ther. 1995 Sep; 18(7):448-52.
3) Schneider et al., Interexaminer reliability of the prone leg length analysis procedure.
J Manipulative Physiol Ther. 2007 Sep;30(7):514-21.
4) Cooperstein R, Lew M The relationship between pelvic torsion and anatomical leg length inequality: a review of the literature. J Chiropr Med. 2009 Sep; 8(3):107-18.
5) Friberg O., Koivisto E., Wegelius C. A radiographic method for measurement of leg length inequality. Diagn Imag Clin Med. 1985;54:78–81.
6) D.W. Rhodes, The relationship between pelvic torsion and anatomical leg length inequality: a review of the literature. J Chiropr Med. 2010 June; 9(2): 95–96.
7) Knutsen, G. Anatomic and functional leg-length inequality: A review and recommendation for clinical decision-making. Part I, anatomic leg-length inequality: prevalence, magnitude, effects and clinical significance. Chiropractic & Osteopathy 2005, 13:11
8) Guichet J-M, Spivak JM, Trouilloud P, Grammont PM: Lower limb-length discrepancy. An epidemiological study. Clin Orthop Rel Res 1991, 272:235-241.
9) Gross, R. H.: Leg length discrepancy: how much is too much?. Orthopedics,1: 307-310, 1978.1307 1978
10) Gross, R. H.: Leg length discrepancy in marathon runners. Am. J. Sports Med.,11: 121-124, 1983.11121 1983
11) Kaufman, K. R.; Miller, L. S.; and Sutherland, D. H.: Gait asymmetry in patients with limb-length inequality. J. Pediat. Orthop.,16: 144-150, 1996.16144 1996
12) Song KM, Halliday SE, Little DG. The effect of limb length discrepancy on gait. J Bone Joint Surg, 1997;79A(11):1690-1697
13) Ha! Just checking to see if anyone is looking at the references. Good for you!
14) Michaud, Thomas, DC. Human Locomotion: The Conservative Management of Gait-Related Disorders. Newton, Massachusetts: Newton Biomechanics. 2011. Pg. 188

Why Gait Analysis is So Important

Finding the Cause of Running Injuries – Why Gait Analysis is so Important
“A preview to the next post containing a big announcement…”

OK, so it’s been over 3 months since the last post.  I know you have all missed it soooo badly!  I will try and be more regular.

As many of you know, I work for Rev3 Triathlon and we have races across the country. I treat hundreds of injured triathletes at these races and so I hear many stories of anguish and despair. Unfortunately, I also get extremely frustrated hearing what they’ve done for treatment. They keep doing the same thing and getting the same result – inappropriate stretches, lifts for “a short leg”, orthotic footbeds, foam rollers, knee straps etc.

I hear their desperation and it’s all too common.  Once injured, runners are anywhere from 60-300% (depending on the study) more likely to be injured again [1-4]. Many studies show that when it comes to runners, the best predictor of an injury is prior injury. What this tells us that unfortunately, the true cause of the injury was never identified, so the problem repeats itself over and over.

When a runner suffers a running injury, the most natural question that follows is “why did this happen?” The runner wants the answer because they want to learn from it and prevent it from happening again.

Many therapists/clinicians try to answer the “why did it happen” question with answers like – “you need an orthotic”, “your arches are too high”, “your arches are too low” or “one leg is shorter than the other.” The therapist is well intentioned and simply repeating what they were educated in back in school.

Unfortunately, they are giving outdated, false and sometimes dangerous information. With better study designs to look at who is getting injured as well as advancements in imaging (3D motion capture, kinematic MRI and flouroscopy) researchers in the past 10-15 years have been able to see exactly HOW the body moves – much of it is in sharp contrast to how we USED TO THINK the body moved. This has made some of the information that used to be taught in schools debatable at best.

The main difference between the old beliefs and the new research is that looking at and measuring a runner in a non-moving scenario (i.e. standing still, laying on the table etc.), is very unreliable and unpredictable at best,, while examining the WAY they run can be much more revealing.

Factors like arch height, leg length, Q angle, tibial torsion, forefoot and rearfoot varus and valgus, subtalar varus and valgus, genu recurvatum and other measurements with fancy names have been measured and don’t correlate to increased incidence of injuries. This has been found in many studies.

Pete Larson did a review of three different studies that show static arch height (meaning when we’re not moving) has very little correlation to the amount of arch height when someone walks or runs.

Another example: A 2004 study looked at 87 recreational runners over a 6 month period. They found that 79% of them ended up with some amount of injury, but “Measurements of static lower limb biomechanical alignment were not found to be related to lower limb injury in recreational athletes. The findings of this study are in agreement with a number of retrospective and prospective cohort studies.[5]

On the other hand, movement analysis of runners is very good at correlating injury to running style and kinematics. This is why a gait analysis (performed by someone who is educated in anatomy and biomechanics) is so important. It is irresponsible for any healthcare provider to not provide or at least refer a patient for a gait analysis if they keep treating the spot that hurts only to have the pain/injury return when a patient returns to running.

That is not to say that gait analysis is the “be all, end all”, but it’s a heck of a lot better than staring at a runner who is standing still and proclaiming that you have figured out why they get injured when they run. If I have to hear one more person tell me they have problem X,Y or Z because they have one leg longer than the other or they have flat feet, I’m going to lose it.  😉

1. Marti B, Vader J, Minder C, Abelin T. On the epidemiology of running injuries. The 1984 Bern Grand-Prix study. Am J Sports Med 1988;16(3):285-94.
2. Taunton J, Ryan M, Clement D, McKenzie D, Lloyd-Smith D, Zumbo B. A prospective study of running injuries: the Vancouver Sun Run “In Training” clinics. Br J Sports Med 2003;37:239-244.
3. Macera C, Pate R, Powell K, Jackson K, Kendrick J, Craven C. Predicting lower-extremity injuries among habitual runners. Arch Intern Med 1989;149:2565-68.
4. Walter S, Hart L, McIntosh J, Sutton J. The Ontario cohort study of running-related injuries. . Arch Intern Med 1989;149(11):2561-4.
5. Lun V., Meeuwisse W.H., Stergiou P, and Stefanyshyn D. (2004). Relation between running injury and static lower limb alignment in recreational runners. British Journal of Sports Medicine, 38(5), 576-580.

Mitigating Declines in Fitness While Injured

So, the last newsletter wasn’t well received.   I have been politely informed that it was too bogged down with minutia. Point taken. Nobody wants to see the sausage making, they just want the final product. Hopefully this edition will redeem the integrity of the newsletters. I put a lot of work into this one and even made literature references!

If you’re pressed for time (aka “no sausage making for me, thanks”) here’s the quick and dirty version of the whole newsletter: If you’re injured, can’t run or do cross-training, you’re in big trouble. You lose significant amounts of fitness in a matter of 2-3 weeks. On the other hand, if you do cross training while you’re injured, you’ll be fine (not ideal, but fine). That’s the newsletter. If you want the details, here is the minutia…

The injured athlete is the perfect expression of frustration. Whether it’s the classic overuse injury like shin splints, iliotibial band syndrome and plantar fasciitis, or it’s an acute injury like rolling your ankle a month before an Ironman.  You just can’t run and it’s as frustrating as people who start sentences with “To be honest with you…”

In either case, there is the overwhelming dilemma: “If I take time off, how much of my previous hard work will be lost?” Let’s take a (quick) look at how time off affects different systems in the body and how to mitigate the losses.

VO2max: The negative effect on VO2max due to detraining varies a bit with different studies, with losses ranging from 4-14% when training is stopped for less than 4 weeks [1-8]. Obviously, the longer the inactivity, the more the negative impact on VO2max., to a point. For example one study found that endurance athletes lost 7% of their VO2max in the first 21 days of inactivity and eventually stabilized at a 16% loss after 56 days [1]. For what it’s worth, you can calculate (here) an estimate that if you normally run a 23:00 minute 5K, a 7% loss in VO2max would result in about 90 seconds (24:30) slower for the 5K.

A different study found that over a 2400 meter run, women averaged 21 seconds slower following 15 days of inactivity. [18]

The better trained you were before the inactivity (higher trained-state VO2max), the bigger its decline when training is stopped [1].

Blood Volume: The majority of the detraining effects can be traced back to decreased blood volume. Total blood volume and plasma volume has been shown to decline by 5-12% [5,7,9,10] within a few weeks.

Stroke Volume: This is the amount of blood pumped out by one heartbeat. This has been shown to decline by 10 to 17% after 12 to 21 days of training cessation [1,2,5]. This is likely due to the decreased blood volume

Heart Rate: Since the heart is now pumping less blood per stroke, (because of the reduced blood volume) the heart has to pump more times. Results confirm this, as sub maximal and maximal heart rate will increase by about 5-10% [1,5,7,9].

Endurance Performance: Swimmers were found to be 7 seconds slower in a 400 meter freestyle swim after 10 days of inactivity [11].  Other studies show a 4-25% reduction in time to exhaustion for endurance trained athletes [4,5-8,12]. The good news is that in runners at least, there was no change in running economy [7]. This means that most of the detraining effects were cardiovascular in nature. This is important because as we will see later, if you can keep your cardiovascular fitness with some sort of cross-training, it will mitigate the negative effects of not running.

So as I mentioned above, I will not get into the details like changes seen in myoglobin, enzymatic activity, lactate kinetics etc. However, I do want to mention that studies show no change in muscle fiber distribution [17], muscle cross section area [7,17]or strength with a few weeks of inactivity in endurance athletes (this does not pertain to strength athletes). Again, this is important to know because it tells us that most of the detraining effects are seen in the cardiovascular system, not the muscular system. So if you keep your cardio training up with a different aerobic exercise you won’t lose as much VO2max, blood volume etc. Not an ideal scenario, but it helps as we see here:

Study 1

32 trained subjects underwent a 2 mile running time trial and had their VO2max tested. They were then randomly assigned to water running, cycling, or running training for 6 weeks.   After 6 weeks of training, all groups made a small but statistically significant decrease in VO2max. Most importantly, regardless of training modality, there was no change in 2-mile run time. It was concluded that over a 6-week period, runners who cannot run because of soft tissue injury can maintain VO2max and 2-mile run performance similar to running training with either cycling or water running [13].

Study 2

Running endurance time and VO2max was tested in 42 untrained subjects. They then went through a 9 week training program of either in-line skating, running or no training. The treadmill time and the VO2max was equally improved in the runners and the skaters, but no change in the control group who did nothing [14].

Study 3

A 5 week training session of either running only, or 50/50 running/cycling resulted in the same amount of improvements in VO2max and 5K time trial [15]

Study 4:

22 Women were assigned to a treadmill, elliptical or stairmaster 3X/week for 12 weeks. At the end of the study, all three groups had similar improvements in VO2max [16].

That’s all for now folks.

1. Coyle EF, Martin III WH, Sinacore DR, et al. Time course of loss of adaptations after stopping prolonged intense endurance training. J Appl Physiol 1984; 57 (6): 1857-64

2. Martin III WH, Coyle EF, Bloomfield SA, et al. Effects of physical deconditioning after intense endurance training on left ventricular dimensions and stroke volume. J Am Coll Cardiol 1986; 7 (5): 982-9

3. 48. Moore RL, Thacker EM, KelleyGA, et al. Effect of training/detraining on submaximal exercise responses in humans. J Appl Physiol 1987; 63 (5): 1719-24

4. Houston ME, Bentzen H, Larsen H. Interrelationships between skeletal muscle adaptations and performance as studied by detraining and retraining.Acta Physiol Scand 1979; 105: 163-70

5. Coyle EF, Hemmert MK, Coggan AR. Effects of detraining on cardiovascular responses to exercise: role of blood volume. J Appl Physiol 1986; 60 (1): 95-9

6. Ghosh AK, Paliwal R, SamMJ, et al. Effect of 4 weeks detraining on aerobic and anaerobic capacity of basketball players and their restoration. Indian J Med Res 1987; 86: 522-7

7. Houmard JA, Hortobágyi T, Johns RA, et al. Effect of shortterm training cessation on performance measures in distance runners. Int J Sports Med 1992; 13 (8): 572-6

8. Houmard JA, Hortobágyi T, Neufer PD, et al. Training cessation does not alter GLUT-4 protein levels in human skeletal muscle. J Appl Physiol 1993; 74 (2): 776-81

9. Cullinane EM, Sady SP, Vadeboncoeur L, et al.Cardiac size and VO2max do not decrease after short-term exercise cessation. Med Sci Sports Exerc 1986; 18 (4): 420-4

10. Thompson PD, Cullinane EM, Eshleman R, et al. The effects of caloric restriction or exercise cessation on the serum lipid and lipoprotein concentrations of endurance athletes. Metabolism 1984; 33 (10): 943-50

11. Claude AB, Sharp RL. The effectiveness of cycle ergometer training in maintaining aerobic fitness during detraining from competitive swimming. J Swimming Res 1991; 7 (3): 17-20

12. Madsen K, Pedersen PK, DjurhuusMS, et al. Effects of detraining on endurance capacity and metabolic changes during prolonged exhaustive exercise. J Appl Physiol 1993; 75 (4): 1444-51

13. Eyestone et al., Effect of water running and cycling on maximum oxygen consumption and 2-mile run performance. Am J Sports Med. 1993 Jan-Feb;21(1):41-4.

14. Melanson EL, Freedson PS, Jungbluth S. Changes in VO2max and maximal treadmill time after 9 weeks of running or in-line skating. Med Sci Sports Exerc 1996; 28(11):1422-6.

15. Mutton DL, et al., Effect of run vs combined cycle/run training on VO2max and running performance. Med Sci Sports Exerc. 1993 Dec;25(12):1393-7.

16. Egana M, Donne B. Physiological changes following a 12 week gym based stair-climbing, elliptical trainer and treadmill running program in females. J Sports Med Phys Fitness 2004; 44(2):141-6.

17. Wilber RL, Moffatt RJ. Physiological and biochemical consequences of detraining in aerobically trained individuals. J Strength Cond Res 1994; 8 (2): 110-24

18. Doherty et al., Fifteen-day cessation of training on selected physiological and performance variables in women runners. J Strength Cond Res. 2003 Aug;17(3):599-607


Heart rate variablility

OK folks, this is a long one, so get comfy. I tried to keep it brief, but this topic is important because it’s something that has the potential to completely overhaul the way we train and you’ll likely hear more on this in the future…

How many times have you gone out for a run or a workout to realize that you just “don’t have it” on that particular day? How many times have you wondered if you’re overtraining because your times aren’t improving, you’re tired or moody? Alternatively, have you ever felt great and wondered if you can train even more than your training plan calls for?

Finding the right intensity, frequency and duration of training is really a bit of a crap-shoot for most of us, but there is some new technology which looks very promising for helping us out. It’s called Heart Rate Variability (HRV) and it refers to the varying intervals between heartbeats.


I am certainly no expert, so I enlisted the help of a friend of mine: Laura V. Weatley is a triathlete, professor and the Coordinator for the Exercise Physiology Lab at Illinois State University. She and her team are currently researching HRV in athletes.

Here’s how HRV works The amount of variability between heartbeats is an expression of the status of your nervous system and your overall health. No, I’m not talking about your heart rate. You’re heart rate is how frequently your heart beats. Conversely, HRV is the variability in the time gap between heartbeats which is an indication of the status of your nervous system.  You want a high variability between beats


HRV is not only influenced by fatigue due to prior exercise sessions, but also hydration levels, stress, sleep (or lack of), nervousness, state of mood, hormonal status, drugs and many other factors.

Laura and her team explain:

” HIGH heart rate variability at rest is a GOOD THING.  It indicates that there is a large time interval between heart beats, specifically in-between the R’s in the QRS wave.  Most of us are aware that a LOW resting heart rate (beats per minute) indicates high cardiorespiratory fitness because the heart can produce a high cardio output (stroke x volume)…and fewer heart beats per minute mean that there is a longer time interval between heart beats.  This equates to high heart rate variability!

LOW heart rate variability during rest is NOT GOOD and indicates that the body is stressed and the heart is working harder; there is a short time interval in-between heart beats.”

Ali Lierman, a senior exercise physiology graduate student studying HRV elaborates:

“A low heart rate variability is NOT good. It indicates that the sympathetic nervous system is active. This can indicate stress and less-than optimal recovery.”
The SYMPATHETIC nervous system is great for getting us ready for activity (fight or flight)- it is responsible for increasing our heart rate, blood pressure, sweating, releasing glucose, and secreting hormones such as epinephrine, norepinephrine, and cortisol.  HOWEVER, at rest, the autonomic system should be parasympathetic-dominant (resting and digesting).

The parasympathetic system allows our body to rest, rejuvenate and recover.  It is responsible for digesting food, optimizing fuel storage and insulin sensitivity, and restoring/rebuilding our bodies and cells.  A high heart rate variability at rest is parasympathetic-dominant, which is a good thing!

Mike Slack, exercise physiology graduate student studying HRV states,

 “a high correlation of low HRV and overreaching/overtraining may likely be caused by the inability of that individual to “shut off” their stress response/sympathetic nervous system activity.”

So here’s the idea: You have your training plan as outlined by your coach, you follow this training plan, you measure your HRV every morning and adjust the training plan accordingly, along with the guidance of your coach. HRV is high? You can afford to work a little harder (you slacker!). HRV is low? You need to take it easy that day.

Laura elaborates,

  “The PROBLEM that we are encountering is that there are no set “standards” for “good” or “bad” HRV values.  This is why we are monitoring athletes and looking at relative values…We are asking the athletes and their coach to give us feedback on the physical and mental stress levels and comparing them to their measured HRV values and athletic performance. We don’t know any universal “good” or “bad” numbers, but monitoring your PERSONAL HRV values over time and correlating them to stress and performance may be a strong tool for determining “athlete readiness.””

 HRV has been used as a prognostic indicator in diabetes, heart disease, depression and many other conditions. I just did a Medline search on “heart rate variability” and found over 4,000 research papers on it. HRV is really nothing new, but it’s application for exercise training is just getting started. This is in large part because the expense of the equipment that is required just to record the data, add to that all of the calculations that need to be done to analyze and interpret the data and you’ve got a nightmare on your hands. However, this is changing…

Polar has a watch called the rs800CX which (from my understanding) records the data, but it costs $500. Suunto has the t6 which records and interprets the data but it is also $400.  I have had difficulty finding info on the web to elaborate further.  However, there is a new relatively inexpensive app for the iPhone/iPad called “ithlete” that also does it all for you (yes, there’s an app for that).

I asked Laura about the ithlete app:

“I personally have not used the ithlete app, but Mike Slack has.  He says that, “ithlete seems to be a great tool for anyone wanting to measure their HRV.  The great thing about ithlete is it’s any easy to use device that measures and TRACKS HRV.  I emphasize tracks because if we don’t know our “optimal” HRV then we have to look at averages and daily fluctuations/trends.  ithlete does this for you and gives you a daily, weekly, monthly trend and a recommendation of rest or decrease intensity/volume.”

 Since HRV is influenced by stress at work or home, diet, sleep etc., you need to pay attention to these things. If your HRV is low, indicating you need to back off your training a bit, you need to account for all of these external training factors.

If you have any questions, please let me know. If I can’t answer them, I will forward them on to Laura and her team.