Conventional wisdom says to stretch before working out or competing, but is it such a good idea? People stretch before an activity to increase range of motion and to prevent injury. However, CBC Radio’s Quirks & Quarks program recently reported that such ideas might not be correct. (Link from Boing Boing.)

Dr. Ian Shrier, Professor in the Faculty Of Medicine at McGill University, noted in the program that “There have been some 24 studies looking at performance and every single one shows that [stretching is] detrimental. You don’t run as fast, you don’t jump as high, and you can’t produce as much force.” When you stretch you actually slightly damage the muscle tissue, which means the muscles themselves perform less well than without stretching — by perhaps 2 – 5%. (This tissue damage is a normal part of stretching, by the by — you also damage muscle tissue when weight training, which means that you also shouldn’t weight train before competition either, obviously.)

What’s more, stretching may not prevent injury, either. Dr. Shrier noted, “We now know that most muscle strains occur when your leg is still in the normal range of motion.” For most atheletes, pulled muscles don’t occur when the muscle is overextended, so the efficacy of stretching to prevent injury is doubtful.

That’s not to say that stretching in general is a bad thing. A martial artist without flexibility is going to have problems. Range of motion will be limited, and some techniques will be impossible to do without flexibility.

I figure this means that before a class, stretching may be okay — just realize that you may be moving slower and with less power than if you hadn’t stretched. After all, in class you may try to increase your range of motion, which tends to push your muscle’s limits of flexibility.

In competition, however, that loss of 2 – 5% of muscle performance could be significant, depending on the activity. A little light activity to warm up the muscles is recommended in lieu of stretching.

Stretching is basically a separate activity from working out. Sure, you can do them at the same time, but you should still regard them as separate. You should certainly be mindful of stretching before a competition, depending on how much of an edge you need.

Just keep in mind that you should warm up your muscles before stretching as well — which usually leads to the new notion of stretching after a workout, rather than before. However, if you’re not putting it after working out, just like with competition, a little light activity will ready your muscles.