The second part of a warm-up regimen, to be performed immediately after the aerobic warm-up and as soon as possible before a practice or match, involves dynamic stretching (stretching muscles while moving).
Throw out the old: Research has shown that the kind of stretching routine most of us have been doing since we were in grade school (holding a stretch for 20 or 30 seconds, supposedly to prepare muscles for exercise, or static stretching) not only fails to do what it is supposed to do but may actually weaken muscles and be harmful.
Studies have found that static stretching weakened muscle strength by as much as 30 percent and that stretching the leg muscles in one leg reduced strength in the other leg for up to 30 minutes after stretching. While a player may think that static stretching increases flexibility, what is actually happening is that the stretching has simply increased the athlete’s mental tolerance for the discomfort of the stretch, while the muscle itself is actually weaker! Studies have made it increasingly clear that static stretching alone before exercising doesn’t reduce the traumatic injury risk.
Bring in the new: Studies show that the new way of stretching (dynamic stretching) increases power, flexibility and range of motion, and may reduce injuries. In one study of female collegiate soccer players, non-contact ACL injuries were reduced by nearly half among players who followed a warm-up program that included both dynamic stretching exercises and static stretching. In another, researchers at Bloomsburg University of Pennsylvania found that golfers were nine times less likely to be injured if they warmed up.