It may sound counter to everything your gym teacher or soccer coach told you, but stretching your muscles and holding them before you run (or hit the ice, the slopes, or the golf course) not only risks injury; it might actually slow you down.

Traditional stretches, like “the flamingo,” the quad stretch of standing on one leg and pulling back the other, are what fitness experts call “static” stretches. While almost all of us have done them ahead of exercising, recent research suggests such stretching before a workout can actually cause your muscles to tighten rather than relax — exactly the opposite of what you want.

What’s more, pulling and holding your muscles before you exercise causes little “micro-tears” that damage the muscle and can lead to injury.

…

Stretching your muscles when they’re cold is a recipe for disaster, say Lum and other fitness experts, such as Nic Martin, the fitness manager at Toronto’s Union Station GoodLife fitness club, and Jennifer Wilson, the director of personal training at GoodLife. A better idea is what’s called “dynamic stretching.” That means slow, even movements that are similar to the moves in your sport.

“It’s about mimicking the movement you’re about to perform,” Wilson says. “You just want to take your muscles, unweighted, through the range of movement that you plan to perform. You’re not holding the position; you’re just getting your body moving.”

So runners, for example, can do a dynamic warmup by simply walking for five to 10 minutes. Tennis players would rally a few balls over the net. Skiers might do a few squats.

“Doing the movement at a slower pace to allow blood to flow into the muscle, that is good preparation. Static stretching is not,” Lum says.

…

As for the idea that stretching before a workout can help prevent injuries? Or the belief that stretching prevents muscle soreness the nest day? Chalk those up to yet more exercise urban myths.

Experts at the U.S. Centers for Disease Control and Prevention who combed through more than 100 studies on static stretching found that people who stretched before exercise were no less likely to suffer injuries, such as a pulled muscle, than others.

And a systematic review from experts at the well-regarded Cochrane Library, that looked at how stretching before or after exercise affected muscle soreness, found consistent findings: “They showed there was minimal or no effect on the muscle soreness experienced between half a day and three days after the physical activity,” the authors concluded.

Despite static stretching’s new-found bad reputation, there is still a place for stretching, particularly if you want to become more flexible. And that place is after your workout.

“You can enhance your flexibility by stretching after your workout, when your muscles are nice and warm; that’s useful,” say Lum.