Saturday, January 23, 2016

The Stretching Debate

Stretching as a means of increasing flexibility and range of motion, and ultimately preventing injury, seems to be conventional wisdom. The number of articles and videos out there espousing the virtues of stretching (especially for runners) is virtually limitless.

As someone with a history of running injuries, I spent a lot of time looking into the causes of my injuries and how to prevent them. I'm not a flexible guy - particularly in my hamstrings (I've never been able to touch my toes) - and this tightness seemed to be the root cause of most of my running injuries. On top of this, my bike fitter seemed pretty dismayed at my lack of flexibility and suggested that this would be a limiter for how low I could go on the front end.

So I set about to rectify this issue with a diligent stretching routine. There are lots of great stretching videos out there - here's an example:


I stretched after every workout, as well as incorporating the foam roller. And it seemed to work. My injuries have been minimal since I got into this routine. But correlation is not causation. Was it the stretching that was making me less injury prone? Or was it some combination or foam rolling, strength work, and perhaps most importantly, being very careful and deliberate about adding volume and intensity to my run sessions? The reality is I can't say for sure what the cause of my injury resistance is, since I can't isolate the various factors. Still, if it seems to work, and certainly isn't hurting, I'd be stupid to stop, right?

The arguments in favour of stretching are numerous, and within the triathlon community it certainly has its proponents:

The early season demand can have one negative effect, which is to make you stiff. Now is a great time to do moderate stretching to improve range of motion and reduce injury.
- Mark Allen (from http://www.xtri.com/features/detail/284-itemId.511713592.html)

If you stretch on a daily basis, even for ten or fifteen minutes, the muscles learn to adapt to that particular movement, and they learn to relax... You’re going to find that your range of motion is going to be enhanced and hopefully prevent some injuries down the road.
- Dave Scott (from https://www.youtube.com/watch?v=BaDXNjFjjnU

Current thinking in the sports medicine world suggest the use of dynamic or movement stretching that mimics the athlete’s movement in sport before activity and static or sustained position hold stretching after training...Hip flexor stretching in combination with hamstring stretching may be beneficial in the treatment and prevention of running-related hamstring injury.
- Joe Friel (from Triathlon Science. Human Kinetics, 2013)

The solution to the problem of tight hamstrings is… to incorporate regular stretching into your training plan so that you can avoid developing tight muscles to begin with. A consistent and effective program of stretching can prevent or at least alleviate many such problems… A study of 1,543 runners in the Honolulu Marathon found that those who stretched regularly following workouts had fewer injuries than those who did not stretch… Stretching after workouts appears to aid the recovery process by improving the uptake of amino acids by the muscle cells. It therefore promotes protein synthesis within muscle cells, which is necessary for full and quick recovery, and maintains the integrity of muscle cells."
- Joe Friel (from The Cyclist’s Training Bible. Velopress, 2009)

Allen, Scott, Friel - these are big names in triathlon and trusted authorities on the subject. And the arguments for stretching are everywhere:

Stretching post-workout can dramatically improve your flexibility over time, which is always helpful in preventing injury. Many athletes incorporate different types and forms of yoga into their existing exercise regimen especially during their pre and off-season workouts. Yoga helps increase flexibility and range of motion, improves balance and muscle strength and has the ability to relieve stress and anxiety.
- Lava Magazine

Most triathletes feel they should stretch more than they do. They are sold on the benefits of stretching, but not enough to actually do much of it. (TJ) Tollakson was one such triathlete until a couple of years ago, when injuries motivated him to finally make a serious commitment to stretching. Now, he says, “Every night I go through a 20-minute stretching routine before I go to bed. I’ve found that it helps a lot with my recovery as well as injury prevention. According to Rountree, stretching is like bodywork in that it is not strictly relevant to recovery. But, she said, “Stretching will keep adhesions from forming. It’s almost like massage from that angle. It’s going to make it easier for you to get into the next workout by keeping you from getting gummed up between the muscle fibers, and between the muscle fibers and connective tissue.
- Competitor Magazine

But there seems to be increasing evidence against stretching. A Study published in the British Journal of Sports Medicine said “Despite a few outlying studies, consistently favourable estimates were obtained for all injury prevention measures except for stretching. Strength training reduced sports injuries to less than 1/3 and overuse injuries could be almost halved.” So... strength training is highly effective, but stretching is useless. Other research suggests that stretching doesn't actually increase one’s flexibility, but “it may be that exercises such as reaching for your toes train the nervous system to tolerate a greater degree of muscle extension without firing off pain signals...In a June 2014 study in the journal Clinical Biomechanics, Tilp and colleague Andreas Konrad found no differences in people's muscles and tendons after six weeks of a static-stretching regimen." (from livescience.com)

While it is true that stretching does improve both range of motion and flexibility, this has not been shown to translate to any other objective markers of performance. Specifically, large trials have shown that stretching either regularly, or before strenuous activity, does not prevent delayed onset muscle soreness (DOMS). Stretching after exercise also does not prevent or lessen DOMS. Worse, several studies have actually shown that stretching may be detrimental to performance. A great deal of evidence now exists demonstrating that stretching reduces both muscle strength and the ability to perform anaerobically—a condition that exists at higher levels of exertion such as when sprinting. These findings have been constant across numerous types of stretching programs and exercises. The most controversial findings though, relate to stretching as a means of preventing injury. While some early studies seemed to show that stretching could prevent injury, more recent ones have shown no such benefit.
- from Competitor Magazine

And many of the most respected coaches in triathlon are firmly in the anti-stretching camp:

Don’t bother stretching. At a minimum, don’t ever employ static stretching before workouts - and mos athletes do not need static stretching after working out. While the jury is still out on the specific benefits of static stretching, if any, for normal, healthy athletes, I have never personally seen any benefits from it. The sport of triathlon does not require a significant range of motion of the muscles or joints, unlike, say, ballet.
- Matt Dixon (from The Well-Built Triathlete: Turning Potential into Performance. Velopress, 2014.)

Stretching is not a matter of injury prevention, but a matter of range of motion. Athletes competing as sprinters or middle distance runners need a certain range of motion. As do hurdlers, who would be well advised to stretch regularly and intensively….But this is where the rubber hits the road. Triathlon does not need extensive range of motion. If taught properly, the appropriate body roll swimming needs uses little range of motion. I’ve seen Olympic champion swimmers with the flexibility of a steel rod. Bike riding requires absolutely none. Even our shortest triathlon event ‎has a minimum of 5km of running, which uses less than 50% of our range of motion. So when posed with the statement: ‘Stretching helps prevent injury’, my answer is in triathlon it doesn't. It creates injury opportunities that would have otherwise not been there."
- Brett Sutton (from https://trisutto.com/stretching-for-triathlon/)

Stretching to improve flexibility is a waste of time, doesn't actually make you more flexible, and can have a negative affect on economy.”
- Joel Filliol (from http://trstriathlon.com/TRSForum/discussion/1401/joel-filliol-says-no-stretching/p1)

But mostly, the research on stretching says that it doesn't make much difference with anything. If it's got a neutral influence, why do it at all? Of course there's a role for other types of stretching, mainly with injury rehab. But I don't think there's any value in the good ol' "let me stretch my hammy so that I don't get injured." A lot of the times, the static stretching is the cause for the injury."
- Paulo Souza (from http://trstriathlon.com/TRSForum/discussion/1401/joel-filliol-says-no-stretching/p1)

So what to make of all this? There certainly seems to be no consensus on this issue. I'm very resistant to giving up stretching - I really don't want to risk returning to that old injury-plagued version of myself. But I have to admit that stretching may not have played any role in my injury reduction. Ultimately, I'm not any more injury prone, so it seems as though stretching is not hurting me at this point. I'm still doing it, but not overdoing it.

A good summary of this debate can be found in an article from Triathlon Magazine Canada weighing the pros and cons of stretching. The conclusion: "We’ve now come to a point where the evidence has tilted towards the negative benefits of stretching for runners and cyclists. So, common sense should dictate whether we should stretch or not and how much we should stretch. Here’s what I mean. If you’ve been stretching and remain uninjured, then by all means continue your stretching program. If you’ve been stretching consistently, and getting injured consistently, perhaps you should back off the stretching or reduce its intensity."

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