By Dr Susan Tyfield (M.Tech.Chiropractic)
Does stretching prevent injuries? This has been a very contentious issue in sports. There are a lot of theories and different evidence on this topic. Let’s take a look at some of the research we do have.
Firstly, keep in mind that stretching before exercise and at other times has been mixed up by many people and we will see that they are different things.
Research has shown that in a series of stretches, after the first stretch, on the next stretch you can actually go further because you feel less pain. This is called stretch tolerance. This can be useful in certain situations to give you pain relief, such as when muscles are in spasm. But in terms of injury prevention, masking pain in this way has the potential to lead to injury.
Another factor to take into account is that our ability to resist injury is also related to the amount of force that a muscle can absorb or generate. For instance, research was done using a machine similar to a Cybex machine, which gives resistance equal to the force that you put out so that muscle strength can be measured. This research found that after stretching, muscle output was actually weaker or less than previously. Similar results were found with both static and dynamic stretching. This may not correlate to injury risk directly, but what athlete would want to be weaker when they head out to train?
It would also seem that eccentric (resistance) contraction of muscles - such as when your hamstring tightens to resist your knee straightening when you’re running - is actually stronger when the muscle is cold (more stiff), rather than warm. Muscles have, in fact, been shown to tear at the same length whether warm or cold.
Don’t get excited though. This doesn’t mean you can abandon your stretching completely, you just need to think about it a bit differently. Instead of only stretching before you exercise, evidence shows that a regular stretching regime in and of itself does seem to increase muscle strength long term. So perhaps yoga can be viewed as weight training after all!
References
Magnusson, S. P., Simonsen, E. B., Aagaard, P., & Kjaer, M. (1996). Biomechanical responses to repeated stretches in human hamstring muscle in vivo. The American Journal of Sports Medicine, 24(5), 622-628. doi: 10.1177/036354659602400510
Shrier, I. (2004). Does stretching improve performance? A systematic and critical review of the literature. Clinical Journal of Sport Medicine, 14(5), 267-273. http://www.ncbi.nlm.nih.gov/pubmed/15377965
Simic, L., Sarabon, N., & Markovic, G. (2013). Does pre-exercise static stretching inhibit maximal muscular performance? A meta-analytical review. Scandinavian Journal of Medicine and Science in Sports, 23(2), 131-148. doi: 10.1111/j.1600-0838.2012.01444.x
Siu, P. M., & Alway, S. E. (2005). Subcellular responses of p53 and Id2 in fast and slow skeletal muscle in response to stretch-induced overload. Journal of Applied Physiology, 99(5), 1897-1904. doi: 10.1152/japplphysiol.00374.2005
