What your gym teacher never told you about stretching before exercise

It’s probably not worth your time

Photo by Pensiero/Flickr

You don’t need to look very far to find advice about stretching and exercise: the oft-cited wisdom is that they should go hand-in-hand, like peanut-butter and jelly or Bonnie and Clyde. You’ve surely heard that a little stretch before and/or after a work-out helps muscles warm up, keeps injuries at bay, and stress and muscle tension away.

Stretching also, apparently, maintains muscle strength. On the aptly named RunningInjuryFree.org blog, the writer claims, “stretching will help strengthen your muscles, enabling you to run better and helping you avoid injury.” The Globe and Mail, which has developed a love affair with running over the last year, has dedicated many column inches and even videos to stretching advice for active readers.

Yet, other mainstream news outlets have made much of studies that show stretching before running has no impact on injury. “Stretching before your run?” the Toronto Star asked smugly. “You’re wasting your time.”

So what are bendy (or brittle) Science-ish readers to make of this conflicting information?

The science shows you may want to think twice about dedicating time to the stretch. In a recent update of a systematic review about stretching to reduce muscle soreness, the investigators examined randomized or quasi-randomized studies of pre-exercise or post-exercise stretching techniques designed to prevent or treat muscle soreness and found that “muscle stretching, whether conducted before, after, or before and after exercise, does not produce clinically important reductions in delayed-onset muscle soreness in healthy adults.” In other words, stretching probably— not definitely—reduces soreness, but the effect is so small as to be barely noticeable. (This conclusion was the same as an earlier systematic review on the same subject.)

Another July 2011 Cochrane systematic review—“Interventions for preventing lower limb soft-tissue running injuries”—looked at the benefits of stretching for runners. It synthesized 25 trials, which included more than 30,000 participants from military recruits, to runners from the general population, to soccer referees and even prisoners. It stated, “Overall, the evidence base for the effectiveness of interventions to reduce soft-tissue injury after intensive running is very weak, with few trials at low risk of bias.” One of the authors of the study, Dr. Ella Yeung (PhD) of the Hong Kong Polytechnic University, told Science-ish, “There is no evidence to suggest that stretching has a protective effect toward running-related injuries.”

Was the time limber readers spent in pretzel-like positions all for naught? We called on one of the kings of stretching studies, Dr. Rob Herbert (PhD) of the George Institute for Global Health in Sydney, to find out. He has conducted two systematic reviews on stretching and exercise, including the first one mentioned in this column, as well as three randomized trials on the subject.

Dr. Herbert told Science-ish not to get “too hung up” about stretching. “If stretching does reduce injury risk and soreness, the effects are very small. If you like stretching, keep doing it because it might have a small beneficial effect (i.e., it might reduce injury risk and muscle soreness by a very small amount). If you don’t like stretching or don’t have time to do it, you’re probably not missing out on much by not stretching.”

Keep in mind, though, stretching may confer other health gains: Dr. Yeung said, “Perhaps there is some psychological benefit or improved circulation.” And stretching increases flexibility. But Dr. Herbert pointed out these are only “transient” increases, which last for minutes or hours after the stretch. “It is not so clear that stretching produces lasting increases in flexibility, although regular stretching clearly does increase tolerance to stretch. So if you think flexibility is of intrinsic value—I don’t—or if you like feeling flexible, regular stretching may be beneficial.”

Going forward, we need more “carefully conducted randomized studies investigating the effects of stretching on performance,” said Dr. Herbert. For now, dear readers, do what you like with your workout but don’t feel the need to bend like a Cirque du Soleil performer every time you’re at the gym just because your high-school gym teacher said you should.

Science-ish is a joint project of Maclean’s, The Medical Post, and the McMaster Health Forum. Julia Belluz is the associate editor at The Medical Post. Got a tip? Seen something that’s Science-ish? Message her at julia.belluz@medicalpost.rogers.com or on Twitter @juliaoftoronto




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What your gym teacher never told you about stretching before exercise

  1. My Chinese neighbour – who hates aerobic exercise, makes comments about student joggers that occasionally pass by and is always going on about wonders of tai chi – would disagree that jogging is good and stretching is bad. 

    I, too, hate jogging so I believe my neighbour is correct in his opinions and I also believe stretching helps body more than jogging does. While we are blaming communists for things we don’t like, I think communists introduced jogging to North America.

    BBC: 

    The ancient Chinese martial art of Tai Chi can help to improve people’s health, research suggests. Doctors in the United States analysed 47 studies looking at the impact Tai Chi had on people with chronic health problems, like heart disease or MS. 

    They found that it could improve balance control, flexibility and even the health of their heart.Writing in The Archives of Internal Medicine, they said it also reduced stress, falls, pain and anxiety.

    http://news.bbc.co.uk/2/hi/health/3543907.stm

    Daily Telegraph:

    Researchers have discovered that the health benefits of aerobic exercise are determined by our genes – and can vary substantially between individuals. Around 20 per cent of the population do not get any significant aerobic fitness benefit from regular exercise, according to an international study led by scientists at the University of London.

    For these people, regular jogging and gym work will do little to ward off conditions like heart disease and diabetes which aerobic exercise is generally thought to resist.

    http://www.telegraph.co.uk/health/healthnews/7147952/Millions-of-people-waste-their-time-by-jogging.html

    • For somebody who is singing the praises of Tai Chi why do you always seem so stressed and agitated about things?

      • Me? You have wrong impression. I am serene as can be. People who read my comments set tone, not me. 

        Just like everyone else I think I am surrounded by nitwits and so I try to educated people so they are not stuck on stupid their whole lives. 

        My heart is pure and my cause is just. :) 

        • In that case I won’t correct your grammar.  Others might not understand our serenity and quest for the edification of others and get agitated.

          For the same reason, I will also not point out that taijiquan dates from approximately 1860, and isn’t particularly old in terms of Chinese martial arts.  Doing so always causes agitation among misinformed adherents.

          More seriously, I’m glad Macleans is largely a political magazine and not a health and fitness journal.  Flexibility is a good thing, but as a middle-aged man who can do the splits, I am entirely unconvinced there is a relationship between what most people do for stretching and flexibility.

  2. Yoga for flexibility and strength, along with aerobics, works for me.  I’m more prone to injury (a sore back and such) without the yoga.

    I would have thought this becomes increasingly important with passing years.  I’ve seen a few senior, hunched over joggers, and have difficulty believing that is as healthy as being a flexible senior jogger.

  3. When I first read the headline “What your gym teacher never told you about stretching before exercise” my immediate reaction was “OMG!  They’ve found a link showing that stretching before exercise causes cancer!!!”

  4. Pre-exercise static stretching does tend to put one at risk, Warming up dynamically to arrive at a level similar to that for the activity you wish to partake in makes sense and prepares the body for what it is about to receive. Along the same lines as training for what you will do prepares you for the task, so does this form of warm up.
    Static stretching after by your own admission, “clearly does increase tolerance to stretch.” This is a good thing and makes static stretching highly desirable for all of us to do. We all walk on snow and ice and slip occasionally, this tolerance to stretching might mean something doesn’t go ping as opposed to the alternative.
    Evidence against stretching increasing flexibility is pretty vague as Doc Herbert said, so this piece really tells us nothing. In fact it tries to discourage folk from stretching at all and not just statically prior to exercise.
    Science-ish indeed, why not report on actual science.

  5. I prefer a good erection .. over stretching ….. and jogging hurts my … oh never mind …

  6. Scientists can talk about this all they like, but why don’t they ever got reports from people that actually do lots of running? I’ve been in cross country groups, and stretching most definitely helps you not pull things! You shouldn’t do it completely cold because you can pull things by stretching too hard, but it works. Stretching to cool down is also helpful but not really necessary. It’s more if you push yourself really, really hard, it can stop you from cramping up as soon as you finish. :)

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