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Medicine Science

Stretching Before Exercising Weakens Muscles 339

Khemisty writes "Back in grade school you were probably taught the importance of warm-up exercises, and it's likely you've continued with pretty much the same routine ever since. Science, however, has moved on. Researchers now believe that some of the more entrenched elements of many athletes' warm-up regimens are not only a waste of time but are actually bad for you. The old presumption that holding a stretch for 20 to 30 seconds — known as static stretching — primes muscles for a workout is dead wrong. It actually weakens them. In a recent study conducted at the University of Nevada, athletes generated less force from their leg muscles after static stretching than they did after not stretching at all. Other studies have found that this stretching decreases muscle strength by as much as 30 percent. Also, stretching one leg's muscles can reduce strength in the other leg as well, probably because the central nervous system rebels against the movements."
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Stretching Before Exercising Weakens Muscles

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  • by dreamchaser ( 49529 ) on Friday November 07, 2008 @10:44AM (#25675267) Homepage Journal

    It's like most things in that too much of even a good thing can be bad for you. It's very important to limber up before a workout, but anything can be taken to extremes.

  • Muscle Cramps? (Score:5, Insightful)

    by eldavojohn ( 898314 ) * <eldavojohn@noSpAM.gmail.com> on Friday November 07, 2008 @10:44AM (#25675269) Journal
    Whenever I took swimming lessons as a kid, we stretched to avoid muscles cramping up in the middle of the water. I would take tired muscles over a leg cramp mid-stroke any day of the week.

    Also when I lift, I would rather be a little weaker than having my arm freeze up as I lift a barbell over my head.

    I don't think I ever had the impression that stretching makes me stronger, just protects me from cramps and overextending. Has this been proven/disproven? I'd be shocked to see so many years of sports medicine overturned by something that could be easily determined through statistics acquired by anyone working out.
  • by ShadeOfBlue ( 851882 ) on Friday November 07, 2008 @10:50AM (#25675357)

    For those of you who don't RTFA, the summary could be misleading. TFA doesn't imply it's best to just jump straight into exercising. Rather you still need to do some warm-up activity (light jogging, jumping jacks, etc..), and then do dynamic stretches, rather than static stretches. What dynamic stretches you should do depends on your sport.

    Furthermore, since this is slashdot, you all probably have terrible posture stemming from over-tight hip-flexors and internally rotated shoulders. Static stretching can be good to loosen the problem muscles. People who bother to stretch usually focus way to much on the hamstrings, when the hip flexors are much more likely to be the problem.

  • by SoupIsGoodFood_42 ( 521389 ) on Friday November 07, 2008 @10:54AM (#25675397)

    That's exactly what I thought when I read the summary. That it can reduce strength is news to me, but I always thought the importance of it was to prevent injury. And given this is a tech site, I don't see why it matters to most of the people here. Hell, most of us probably don't get enough exercise to begin with, let alone taking it to the level where performance matters.

  • by multisync ( 218450 ) * on Friday November 07, 2008 @10:57AM (#25675431) Journal

    That was my thought. 20 - 30 seconds is far too long to hold a stretch before exercise. A warm up should be just that - moderate activity to get the muscles ready for your workout.

    When I run, I start with a brisk five minute walk, followed by some easy stretching before I begin my run, but I won't hold a stretch for more than ten seconds. You can also just stretch as you do your warm up, by walking on your toes, kicking your butt, and basically walking like you're applying for a government grant.

    The 30 second stretches are for after your workout, during the "cooling off" period.

  • by characterZer0 ( 138196 ) on Friday November 07, 2008 @11:06AM (#25675555)

    Can we please cut it out with the everybody-interested-in-technology-is-a-fat-slob jokes? And the everybody-interested-in-technology-is-socially-inept-and-has-no-luck-with-the-opposite-gender jokes? Seriously, it's getting old.

  • MOD Parent UP (Score:3, Insightful)

    by Don_dumb ( 927108 ) on Friday November 07, 2008 @11:10AM (#25675597)
    Agreed. In the UK in the nineties we were taught to warm up and then to hold a stretch for 8-10 seconds (it was really just 8 but 10 was taught as it was 'easier' to remember). This hasn't really changed in gym practice, although some sports coaching has embraced dynamic stretches. Personally I have tried dynamic stretching and found that it didn't go far enough. It possibly doesn't help that I swear by static stretching (after warming up and at the end of exercise) and am quite limber in many areas.

    The 20+ second stretches were never taught, it was 16 post exercise.

    Now I know there is a lot of evidence to suggest that pre-exercise stretches are not-necessary but personal preference. I personally would not do anything that puts my joints to the limit (such as kicking or dumbbell flys, etc) without stretching the relevant muscles beforehand. I guess the principle for me is that a static stretch, takes the muscle further than the acutal action and therefore loosens the hamstrings et al so they don't snap when used in anger.

    The problem many people have is that they stretch when cold and that is simply counter productive or just plain dangerous.
  • by MrNaz ( 730548 ) on Friday November 07, 2008 @11:19AM (#25675707) Homepage

    I think this entire article is a load of attention seeking BS, and I will not believe a word of it until I see a proper peer-reviewed research paper in a medical journal that debunks stretching.

    While I'm sure that it is possible to overstretch a muscle, especially if you isolate one muscle and use all your opposing musculature to stretch it excessively, the implied message of this article is rubbish. There is absolutely no evidence that stretching before exercise weakens muscles (note I used the exact same phrase as the title) so long as you don't over do it.

    In other news:

    Breathing is bad for you!
    Hyperventilating can result in a situation where you remove too much CO2 from your bloodstream leading to a failure of the breathing reflex, resulting in hypoxia and in extreme cases brain damage or death).

    Exercise is bad for you!
    Bodily ligaments and tendons wear out, just like any other mechanical part, so the more you use them the faster they wear out. The body does have a regenerative effect, but it is not unlimited and the deterioration of the body's ability to maintain joins manifests in arthritis and other related conditions.

    Water is bad for you!
    You can drown.

    These articles brought to you by the Department of Attention Whores with no Sense of Truth or Accuracy.

  • by Anonymous Coward on Friday November 07, 2008 @11:31AM (#25675893)
    Sounds like someone needs to get laid.
  • by gsgriffin ( 1195771 ) on Friday November 07, 2008 @11:42AM (#25676079)
    I agree. The truth hurts too much!
  • by Culture20 ( 968837 ) on Friday November 07, 2008 @11:46AM (#25676135)

    It's been around for a while (at least 8 years).

    Try 30+ years

  • bad assumption (Score:3, Insightful)

    by J05H ( 5625 ) on Friday November 07, 2008 @11:58AM (#25676311)

    static stretching is not for warming up before athletic performance - it is for increasing flexibility. Of course it would result in weaker muscle output - the goal of that kind of stretch is to slightly pull the muscle - similar in effect to muscle-tearing during a heavy weights workout - the torn/stretched muscle then should be given the opportunity to heal in it's new configuration.

    Again, it's not supposed to generate more muscle power.

    To properly warm up for a game or athletic performance, you want to stretch some but mostly do repetitive movement. Start small and build up to wider movements. Also for raw power, don't discount heart rate and oxygen uptake - being "up to speed" on heart is in many situations more important than warm muscles.

  • by Anonymous Coward on Friday November 07, 2008 @12:03PM (#25676395)

    The word "acute" in the title of 3 out of 4 of those papers highlights that what I was saying, i.e., it is not stretching but over stretching that is bad for you. I don't think these papers would suggest that a rugby player get to the field and get into the scrum 20 minutes after getting out of bed and with no preceding activity.

    Well done, it's not often that someone can actually cite references to prove that they missed the point.

  • by russotto ( 537200 ) on Friday November 07, 2008 @12:15PM (#25676509) Journal

    Can we please cut it out with the everybody-interested-in-technology-is-a-fat-slob jokes? And the everybody-interested-in-technology-is-socially-inept-and-has-no-luck-with-the-opposite-gender jokes? Seriously, it's getting old.

    Sure, we'll stop right after we stop the jokes about lawyers being unethical, plumbers showing way too much buttcrack, politicians lying, and sharks wearing frickin' lasers. (OK, that last one may not fit in)

  • by Anonymous Coward on Friday November 07, 2008 @12:45PM (#25676847)

    There are many papers on the subject. Yes, there is still work to be done to answer all the questions, but your ridiculous statement that there is absolutely no evidence that stretching (static) before exercise weakens muscles just shows that you haven't bothered to read about it.

    There's a really subtle point that a lot of this work seems to overlook. Muscles are length dependent force generators, meaning that they'll produce more force at longer lengths. One of the things that happens during a prolonged static stretch is that the tendons creep a little, meaning that, at the same joint position, the muscle itself is at a shorter length. If you measure force, stretch, then measure force again at the same joint configuration, you're not measuring the muscle in the same configuration.

  • by ShieldW0lf ( 601553 ) on Friday November 07, 2008 @01:25PM (#25677277) Journal

    I've always thought about it in terms of steel cables and rubber bands.

    If I tie one end of a steel cable to a load that is stuck in the mud and the other end to the back of my truck, and leave it slack, and floor my truck, I'm going to get more snapping power to dislodge the load, but I'm at higher risk of breaking the cable.

    If I tie one end of a bungee cord to a load that is stuck in the mud and the other end to the back of my truck, and leave it slack, and floor my truck, the elongation is going to sap a lot of my snapping power, making it more difficult to dislodge the load, but I'm at a much lower risk of breaking the cable.

    Static stretching is what puts slack into the cable. Dynamic stretching is what puts bungee into the cable.

  • by Anonymous Coward on Friday November 07, 2008 @02:31PM (#25678235)

    What the hell are you talking about? Did you even READ any of the article titles or abstracts?

    Only ONE article refers to an "acute bout of stretching," one article has acute in the title (which is talking about Acute EFFECTS, not acute STRETCHING), and another features acute in the abstract but is referring to the possibility of acute effects FROM stretching.

    And that was out of the 7 articles he posted links to, btw.

    I think he proved that you don't know what you're talking about and you proved that just talk out of your ass with that accusation.

    (just for the record, I didn't set out to prove you're an idiot, I just looked at the articles on my own and noticed your bullshit "3 out of 4" comment - apparently you can't count either :P)

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