Attend any sporting event from grade school children to professional athletes and you will notice one thing in common; they are all stretching before they begin competing. It has been widely accepted for ages that stretching is a fantastic way to warm up the body and prevent injury. But does the science support this? Recent publications in exercise science journals are finding that stretching not only doesn’t improve performance and prevent injury, it actually makes athletes perform worse and increases the chance of injury. Yup, we had it all wrong.
A New York Times article published back in 2013 embellishes on the findings of these studies. One of the studies published in The Journal of Strength and Conditioning Research found that static stretching before lifting weights made athletes weaker! The New York Times article also describes a meta-analysis done at the University of Zagreb where researchers compared hundreds of past experiments involving stretching and found that static stretching reduced strength by an average of 5.5%. They also found that the longer you hold the stretch, the greater the reduction in strength will be. These two studies along with countless research being published in PubMed have clearly shown that stretching prior to exercise makes you weaker. So if you’re going to weight train or compete in weightlifting, don’t stretch.
Well, this is another area where people get confused. Flexibility can be enhanced to a certain degree; limited by genetic factors the same way strength and body composition improvements are limited by genetics. Those born with short tendons and long muscle bellies can exhibit more flexibility and improve flexibility to a greater extent. Contrary to what Pilates tells you, you can NOT lengthen a muscle. Your muscle length and tendon length will remain fixed throughout your entire life.
This is due to a thinking error called survivorship bias. When we look at people who do Yoga and Pilates, we only see those who succeeded in the physical demands of the activity; usually by the aid of favorable genetics for the particular activity (flexibility). We do not see the countless individuals who failed and are no longer participating. As a logical error, we conclude that the activity created the physical attributes which allow success in the activity while the truth is the inherited physical advantage is the reason these people choose Yoga or Pilates; because they are able to do it and it is relatively easy for them.
For example, we wouldn’t say that basketball makes people taller, right? Tall people gravitate towards basketball because they have a physical advantage; height. In the same sense, flexible individuals gravitate towards Yoga, athletes gravitate towards cross fit, thin people with a high amount slow twitch muscle distribution gravitate towards running and biking etc. (slow twitch muscle fibers are “endurance” fibers and individuals with a lot of this fiber type throughout his or her body have better endurance).
Simply using your muscles with low intensity to prime the nervous system and get blood into the muscle. A light walk or a light jog would be a great warm up before competing in sports. Practicing the skills involved with the particular sport would also be an excellent way to warm up as well such as swinging a bat (NOT weighted) before hitting a baseball or taking some jump shots before a basketball game. Prime the nervous system to wake up the motor pathways associated with your sport and get blood into the muscles so they’re ready to do what the nervous system asks of them.
Now, if you enjoy stretching, then go for it! Some people feel much better after a nice stretch and there is nothing wrong with that. All I am saying is that if you want peak performance, avoiding it appears to be a better approach based on data. I am also saying that one should not feel obligated to stretch for reasons such as recovery from a workout, improved flexibility, and mobility, or any other mythical improvement which has been disproved by physiology and research.
Owner of BioFit
Journal of Athletic Training, National Athletic Trainers Association. Stretching Before and After Exercise: Effect on Muscle Soreness and Injury Risk – J. C Andersen
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