According to a 2011 review in the Cochrane Database of Systematic Reviews, stretching didn’t reduce lower-body injuries in different levels of runners. However, many of the studies on stretching and injury prevention for runners use different stretching techniques such as static or passive stretching and different lengths of time to hold the stretch, according to a 2010 study in Current Sports Medicine Reports.
It’s possible that dynamic stretching (rather than static stretching) before running could improve endurance running performance, according to a 2015 study in the Journal of Strength and Conditioning Research. Dynamic stretching usually involves moving a joint quickly through a specific range of motion, such as flexing your knee joint while standing so your foot kicks your butt. Compared to runners who didn’t stretch, the dynamic stretchers could run longer to exhaustion.
Runner’s World also suggests saving those longer, passive stretches for after your run to help your body cool down while also improving flexibility. Stretch your hamstrings, hip flexors, quads, and calves for at least 30 seconds per leg.