It’s a common and persistent myth that static stretching improves running performance and decreases the risk of injuries, researchers say.
Instead, an active warm-up can help with running performance, and progressive training can reduce injury risk, they write in the British Journal of Sports Medicine. There’s evidence stretching can help keep joints flexible and that it won’t harm performance, but it won’t help either, they write.
Source: No Evidence Stretching Prevents Running Injuries
Steve Parker, M.D.