When should I stretch?
Stretching is one of those topics that it seems you will hear a completely different story depending on who you talk to. “nobody stretches enough”, “no, don’t stretch before exercise!”, “don’t bounce in stretches”, “don’t hold any stretches!”. It’s enough to make your head spin! In this month’s blog I’ll talk about what stretching is, the different types of stretching, when/when not to stretch, and the big question: does it actually do anything?
What is a “stretch”?
By definition, a stretch is “an act of stretching one's limbs or body.” Well, duh. So what do we typically mean we talk about stretching? For the purpose of this blog I’m going to stick with muscle stretches. There’s also joint mobility drills and self mobilizations, but we’ll put those in a different category. Let’s break this down to specifics. Muscles are groups of fibers of elastic soft tissue that contract and relax to move the body. At the ends of muscles, they become tendon, which is usually smaller and less elastic. The tendon is what attaches to bone. When a muscle contracts, the two bones it’s attached to move closer together. To stretch a muscle, the goal is to lengthen it, so the two bones should move further apart.
Types of stretches
There are two primary categories of stretches: static and dynamic. This is relatively straightforward, static stretches are held, typically 20-30 seconds. Conversely, dynamic stretches aren’t held for a length of time, the body just moves through the stretch in a slow and controlled manner. Typically, it is recommended that you do dynamic stretches as a component of your warm-up or pre-event, and static stretches after.
What does the research say?
Here’s the kicker: there is no research that says stretching helps. There’s actually some research that says stretching can be harmful. Mind-blowing, right? Let’s break it down. In terms of “harm”, there was a review in 2011 that showed limited ability of the muscle to produce force after static stretching. For example, if you stretch your quads for thirty seconds each prior to squatting, you’re less likely able to complete as many reps or do as much weight.
What about delayed onset muscle soreness? There’s one study that showed stretching can reduce inflammation in muscles, but several other studies specifically looking for a correlation between stretching and reducing DOMS came up short.
And lastly, my bread and butter: injury prevention. Does stretching help? The research says no. There have been several studies comparing large groups of athletes and soldiers doing the same work, but only half of them perform static stretching. All off the studies had basically the same result: no difference in rate of injury between groups.
The bottom line
Here’s what to take from this: stretching is not the cure-all, and overall probably not very important. But here’s what I want you to think about:
All of the studies I discussed in this blog are based on static muscle stretches, there’s little research on dynamic stretching.
Again, this is all based on stretching muscles; I’ll get more into joint mobility in my next blog (that’s where the magic happens).
If you like stretching after your workout (remember, static stretching prior to performance has been shown to be a bad idea), go ahead and do it! All research is limited to an extent, and if what you’re doing is working for you, there’s no reason why not.
References
Berrueta L, Muskaj I, Olenich S, et al. Stretching Impacts Inflammation Resolution in Connective Tissue. J Cell Physiol. 2016 Jul;231(7):1621–7.
Brushøj C, Larsen K, Albrecht-Beste E, et al. Prevention of overuse injuries by a concurrent exercise program in subjects exposed to an increase in training load: a randomized controlled trial of 1020 army recruits. Am J Sports Med. 2008 Apr;36(4):663–670.
Hart L. Effect of stretching on sport injury risk: a review. Clin J Sport Med. 2005 Mar;15(2):113–113
Herbert RD, de Noronha M, Kamper SJ. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2011;(7):CD004577.
Kay AD, Blazevich AJ. Effect of Acute Static Stretch on Maximal Muscle Performance: A Systematic Review. Med Sci Sports Exerc. 2011 Jun 8.
Lund H, et al. The effect of passive stretching on delayed onset muscle soreness, and other detrimental effects following eccentric exercise. Scand J Med Sci Sports. 1998 Aug;8(4):216–21.
Pereles D, Roth A, Thompson DJ. A Large, Randomized, Prospective Study of the Impact of a Pre-Run Stretch on the Risk of Injury in Teenage and Older Runners. USATF.org. 2011 Jun 15.
Weber MD, Serevedio FJ, Woodall WR. The Effects of Three Modalities on Delayed Onset Muscle Soreness. Journal of Orthopaedic & Sports Physical Therapy. 1994;20(5):236–42.