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September

Stretching. The ___ the Bad and the Ugly (Where is the Good?)

It’s much easier to present evidence to someone who has no opinion vs. someone who already has preconceived ideas. Such is the case with stretching. For decades, the dogma has been that stretching is good for you. In some cases this is true, however when put to the test in research, stretching not only falls short of its intentions, it can be detrimental. I don’t mean to sound dramatic with that statement. Stretching is not catastrophic. It merely has the potential to be detrimental, so I think you should be aware before you stretch.

Pic source
Pic source

 

Keep in mind that when I mention stretching in this post, I am referring to static stretching (i.e. stretch and hold), not dynamic stretching (i.e. rhythmically moving a joint through its range of motion). So, without further ado, here we go…

Stretching: Injury Prevention and Athletic Performance

For the past 15 years, we have known that stretching prior to exercise does not prevent injury. The British Journal of Sports Medicine published a lengthy review of the topic in 1999 and concluded, “The basic science literature supports the epidemiologic evidence that stretching before exercise does not reduce the risk of injury.” Since then, many other papers concluded that stretching does not prevent injury. Those published in reputable medical journals include these ones in 2000, 2001, 2002, 2003, 2008, 2011, 2013 and there are quite a few other studies.

With all those studies and reviews pointing out that static stretching doesn’t reduce injuries, I have to throw out a small caveat. There are a couple studies (Small in 2008 and McHugh in 2010) that found that static stretching does not reduce overall injuries, but may reduce muscle strains. There was also this 2010 study that showed stretching “does not appreciably reduce all-injury risk but probably reduces the risk of some injuries” See if you can wrap your head around that ambiguous statement! (full text is available on the link I provided).

However, when weighing all the research, we can safely state that the overwhelming evidence shows that stretching prior to exercise does not reduce injury.

At this point, some zealots may wish to continue stretching before exercise. After all, “What’s the harm?” The harm comes in the form of a significant reduction in performance. What exactly do I mean by that? Well, static stretching has been shown to (at least temporarily)

  • reduce muscle strength output (2001), (2008),
  • reduce muscle strength endurance (2005),
  • reduce sprint performance (2008, 2008, 2007),
  • reduce shuttle run performance and vertical jump height (2005, 2005, 2014)
  • reduce performance in endurance running (2010),
  • reduce power and agility performance (2006),
  • reduce balance, reaction, and movement times (2004)

Some people argue that the reduction in performance is dose dependent. In other words, if you don’t hold the stretch too long, the degradation in performance won’t be too bad. Studies are mixed on that thought: This 2014 study found that no change was present in jump performance with a 30 second stretch hold, but jump performance was reduced with a 60 second hold time. This 2006 study found that strength output was reduced with a 30 second stretch hold, but was worse following a 60 second hold. Contrary to those studies, this 2006 study found that there was a similar reduction in strength output regardless of whether the stretch was 15 seconds or 30 seconds. Therefore, whether the detrimental effects are dose dependent is still up for debate. Lastly, this 2014 study found that 30m sprint performance was reduced even 24 hours after static stretching.

So if stretching before exercise is a bad idea, why stretch at all? I can think of 3 other reasons why people stretch and hold:

1. Stretching as Treatment for an Already Injured Tissue.

I hear this on a daily basis – New patients present to my clinic reporting for a muscle/tendon injury and soo they started “stretching the #$&@ out of it.” I would argue that your body is trying to mend the torn tissue, and you stretching it is disrupting that process. It’s like being married to a spouse who is in a bad mood – you just have to let them be – pestering them about their mood will not help!

Unfortunately, the research is sorely lacking on this. To my knowledge, there has been only one study where injured patients were split into two groups – one told to stretch and the other not. This was on hamstring injuries and the group who was put in the “more intensive stretching program” resulted in better mobility and earlier return to play (contrary to my views on stretching an injured muscle). However, I don’t have the full text of that study, so I don’t know what the differences between the treatments were in each group or any other details.

Contrary to that study and contrary to conventional public beliefs, the medical literature OPINION is firmly against aggressively stretching an acute muscle strain or tendon injury. For example:

  1. American Journal of Sports Medicine, 2005 Muscle Injuries: Biology and Treatment: “We also instruct the athlete to move very carefully for the first 3 to 7 days after the injury to prevent the injured muscle from stretching.”
  2. ISRN Orthopedics 2012 Treatment of Skeletal Muscle Injury: A Review:…early mobilization also has disadvantages. The scar that is formed will be larger, and reruptures will be more common. Therefore, rest is advised during the first 3 to 7 days to allow the scar tissue to gain strength. Subsequently, mobilization within the pain free limits is initiated.”
  3. Best Practice and Research Clinical Rheumatology 2007 Muscle Injuries – Optimizing Recovery: “We also instruct the athlete to take things very carefully for the first 3–7 days after the injury to prevent the injured muscle from stretching in any way.”
  4. J Orthop Phys Ther 2010 Hamstring Strain Injuries: Recommendations for Diagnosis, Rehabilitation and Injury Prevention: “Excessive stretching of the injured hamstrings should be avoided, as this can result in dense scar formation in the area of injury prohibiting muscle regeneration.

2. To Increase Range of Motion

If you suffer from limited mobility in a particular range of motion (ROM), you may want to stretch the tissues that are limiting that motion. However, as outlined above, there may be concurrent detrimental aspects to stretch and hold. Methods other than static stretching can be employed to increase ROM. For example,

  1. Myofascial Release Therapies: A review of the literature performed in 2014 , found that myofascial release therapies (Active Release Technique – ART is highlighted in the paper) are effective at increasing ROM and flexibility WITHOUT the concurrent detrimental aspects of force production or performance that are typically seen with static stretching. I spoke with one of the authors of the study (Darin Padua, PhD, ATC) and he stated that even though the paper was just published, there have been several new and better studies published since they submitted their article and it being accepted and published.
  2. Strengthening: One thing that most people don’t realize – stretching does not change the structure of a muscle or tendon. It is thought that the increased ROM seen with stretching is mostly neurologic tolerance. Strengthening does actually change the structure of a muscle and tendon. As such, strengthening (eccentric strengthening in particular) has been shown to improve ROM and/or flexibility just as much, if not better than static stretching (2004, 2007, 2008, 2009, 2009, 2012 ). Eccentric strengthening will not only give the benefit of increasing flexibility and ROM, but also potentially give the added benefit of injury protection and improved performance.

2. General Health Benefits.

Some people just want to be more flexible. I get that. However, stretching to increase ROM in a joint/muscle/tendon that already has adequate mobility is going down a path that I’m not sure I would want to go down. There is convincing evidence that HYPERmobility (too much ROM) is a greater risk for injury than HYPOmobility (too little ROM). For example,

  • This 2014 study looked at over 800 women participating in a variety of physical activities over 100 weeks and found there was significantly more injuries in the women who had greater ROM’s
  • This 2012 study on English Premiere League soccer players found that hypermobile athletes had a higher incidence of injuries and were more likely to experience at least 1 injury, a reinjury, and a severe injury compared with non-hypermobile athletes.
  • A 2010 review paper pooled the data from 18 papers and concluded that general hypermobility resulted in a near 5 fold increased risk of knee injuries for athletes participating in contact sports .
  • So you’re a dancer or a gymnast who needs better flexibility? Fine, just be cautious… This 2013 study found hypermobility in certain joints increases injury risk and that, “Young dancers (less than10 years of age) should not be exposed to overload (especially of the back) or extensive stretching exercises.” That same study referenced another study that found, “joint hypermobility required by many dance styles may increase the risk of tendinopathy.”

  Am I saying activities like Yoga and Pilates are bad for you?  No, I’m not saying that.  They is a great deal more to those practices than just the stretching aspect.  There is an inherent component of novel movements, body control, movement variability, balance and coordination that are paramount in those practices.  So hold the hate mail.  I’m not saying Yoga and Pilates are bad.

Summary/Take Home Points

Does this mean that static stretching should NEVER be done? No, I’m not saying that. The main take home points are the following

  1. Static stretching for injury prevention has not been proven; in fact it has been overwhelmingly proven NOT to help
  2. Static stretching results in reduced power output and performance (at least temporarily
  3. Generalized stretching just for the sake of stretching is unwarranted and potentially increases risk of injury if there is too much mobility
  4. If you have limited ROM/flexibility, stretching is fine, but be aware there are equally beneficial methods in the form of manual myofascial release (such as ART) or with eccentric strengthening.

I am a firm advocate of movement screening with the SFMA. The SFMA is a series of movements developed by an advisory committee of orthopedists, chiropractors, physical therapists and athletic trainers. They developed 7 simple movements that everyone should be able to perform. If you cannot perform them, the evaluator can break the movement down into its individual parts in order to discover the reason for the faulty movement. AT THAT POINT, you can start a program to address any ROM/flexibility deficits you may have. However, stretching just for the sake of stretching, I feel is a poorly thought out plan.

I first wrote about the pitfalls of static stretching 3 years ago and was surprised back then at how popular opinion hadn’t caught up with evidence. Here we are 3 years later and the London Marathon website still says, “stretching can help protect your body from the impact of running on the road, while reducing muscle soreness and the risk of injury to muscles, joints and tendons.” Ironically, it is on their page titled “The Perfect Warm-Up“. It seems that though stretching is the modern day equivalent to Bilbo Baggins and the One Ring. It keeps calling out to people and making them do things they shouldn’t be doing and they just can’t stop themselves.

- Kevin Maggs, ,

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