Stretching is actually the third leading cause of injury to runners. If you like to stretch for other reasons, or you have a medical problem that requires stretching, then stretch as needed. But don't expect stretching to prevent injuries or help you warm up for a recreational run or distance race.
As opposed to almost all other sports, distance running is best done within your mechanical limits. While stretching is beneficial if you participate in sports that require you to go beyond the normal flexibility boundaries of your body, it can leave runners with more aches, pains and injuries than they receive from their running.
If you like to stretch, the best time is in the evening, say, just before bedtime. You want to be relaxed, and not rush through a stretch routine.
Those who stretch immediately before running, immediately afterward, or during, have a higher rate of injury than do those who don't stretch at all.
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