Sunday, 22 January 2012

Does Stretching Work?

I had a revelation today while partaking in my daily yoga routine- I am, by far, the most inflexible person in the world.  Hands down.  

Just kidding, I don't do yoga.  I really do not stretch either.  But, maybe I should...then I could be just as awesome as this guy.  I highly recommend you click on that link- the man is amazing!  If there are people like that in the world, then why can't I even touch my toes? 

Anyway, if you're like me, and you don't stretch, are we doing ourselves a disservice?

Well, the answer is a little complicated, but that is what I want to explore with today's blog.  Also, I should mention that I was first exposed to some of the articles referenced in this article at (if you haven't checked it out, you should).

Does it help muscle soreness?

One of the most common reasons why people stretch is to reduce muscle soreness.  In preparation for (or to recover from) a hard workout, it is common practice to throw in some stretching to try and reduce how sore we feel the next day.  But, does this really work?

A 2011 study published in the Cochrane database  holds the answer to this question.  If you have never heard of the Cochrane database before, check it out- it is essentially where all the highest quality health care studies are pooled together to look for consistencies (or inconsistencies) in their results. 

In this review, 12 studies were included.  With a high level of consistency, the studies showed that pre-exercise stretching reduced soreness by about 0.5 on a 100-point scale.  In addition, post exercise stretching reduced soreness by a whopping 1 point on the 100-point scale.

So what does this show?  Well, if you are stretching acutely before or after an activity to reduce soreness relating to that specific activity, you are probably wasting your time.  That does not mean stretching is useless (we will get to that), but it just means that it does not fulfill this use.

How does stretching impact performance?

Well, it is widely accepted now that stretching decreases performance in power or strength oriented events (like jumping, shot put, power lifting, sprinting).

That being said, how many of you still stretch prior to participating in endurance events?  If you do, maybe you shouldn't.  Some relatively new research shows that stretching may also  decrease endurance performance.  This 2010 study looked at the impact of static stretching on endurance running.

In the study, collegiate runners were put through 2 separate 60 minute time trials; 1 with stretching before, and 1 without stretching.  The 60 minutes were separated into two components:
  • First 30 mins: the running intensity was was kept at a constant (65% of their VO2 max)
  • Second 30 mins: the runners were told to go as far as they possibly could

Interestingly, this study showed that on both accounts, the non-stretching trials out performed the stretching trials.
  •  First 30 mins: the non stretchers burned significantly fewer calories than the stretchers (425 vs. 405 kcals) 
  • Second 30 mins: during an all out effort, the runners went 3.4% further when they did not stretch
What does this show about stretching?  Well, if you do it before an endurance event, it will have a detrimental impact on your performance.  On a side note- keep in mind that this study was looking at static stretching only.

Does stretching reduce injury?

Stretching has to be good for something, doesn't it?  How about preventing injury?  This study, which is comprehensive review article, shows that the evidence is pretty inconsistent when it comes to the role of stretching and injury prevention.

This uncertainty arises because many of the individual studies referenced show that stretching has no impact on the frequency of injuries.  Check out this full text article which shows that among 1538 army recruits, their regular stretching regime had no impact on the frequency of injuries.

So does stretching help prevent injuries?  These studies suggest that in general, it does not.  However, there may be more to this than meets the eye.  So before you give up on stretching forever, keep reading...

My take on stretching and injuries: 

The above research does cast a shadow on the role of stretching in preventing injuries.  However, there is one key flaw that all of these studies fail to take into account: the cause of and the type of injury.

For example, there are many studies showing that stretching alone has very little impact on low back pain.  Does this mean that stretching is never good for low back pain?  No.

One thing that should be kept in mind when interpreting stretching and low back pain research is that there are a number of causes for low back pain. If your low back pain is originating from an instability (or too much motion), then why would stretching help? By the same logic, it would seem that the hypomobile painful back (stiff, not enough movement) may be more likely to respond to a stretching regime. Unfortunately, these two types of low back pain are not separated in the studies looking at stretching as an intervention.

So, some subjects might see benefit (probably the hypomobile individuals), and some subjects might feel worse (probably the overly flexible group).  Unfortunately, this averages out to the conclusion: stretching does not have an impact on low back pain.

The solution to this problem comes down to classifying injuries into different subsets before accurate conclusions about specific interventions can be drawn. This is where the research is headed, but we are still trying to figure the best classification system out.  For instance, check out this example for the classification of low back pain.


Here are your takeaway points:
  • Stretching does not reduce post exercise muscle soreness
  • Stretching has a negative impact on both strength and endurance oriented activities
  • Stretching is not good for ALL injuries (but is potentially very useful for some). 
At the end of the day, I hope this article helps prevent some of you from stretching for the wrong reasons.  But, I also want to make sure you are not scared to stretch- there are benefits (but maybe just not as many as we once thought)!  For instance: squeezing into a box.

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