I am too busy right now to do any in depth posts, so here's a quick little review of an interesting study I just read. I’ve written several times before on this blog about how unilateral exercise can have significant effects on the contralateral side. I find this interesting not just because it’s kind of cool but because it is an elegant way to prove the extent to which adaptations to exercise are central as opposed to local. I’ve also written about how stretching seems to suck. Well I recently read a study which shows that stretching is good for something, and that it can have cool effects on the opposite side of the body. Here’s a brief discussion of the study.
Researchers asked subjects to stretch their right calf muscle 3 times per week for 10 weeks. After this time, subjects experienced an 8% increase in range of motion at the ankle, as well as a 29% increase in the one repetition maximum strength at the ankle. They also gained 11% greater 1RM strength on the contralateral leg, which didn’t do any work at all.
Nice job stretching!
Interesting information to keep in mind next time you are trying to preserve strength and/or range of motion in an injured limb during a rehab period.
To me this is just a curiosity, or a little hack or trick, not something I think will change the way people train. But I do think it illustrates a general principle that is very applicable - that strength and other qualities we assume to be local are in fact more centrally governed than we imagine, and the governor can be effected by a wide variety of factors, including simple sensory feedback.
I don't have the full text of the paper but a summary prepared by Chris Beardsley and Bret Contreras states that one of the mechanisms for crossover in the case of unilateral strength training is thought to be modulation at the spinal cord level. For example, unilateral electrical stim has a crossover strength effect. So they wondered whether stretching would do the same as the stim. And it did. Cool, but it won't get me stretching.
What do you think? Let me know in the comments below.