Are your hamstrings perpetually wound tight like coils? Sports physiologists at the University of Wisconsin-La Crosse have the remedy for tight hamstrings: Foam rolling three times a week for 3×20 seconds per leg significantly improved flexibility without reducing athletic performance
Contrast that with static stretching, which “is like ripping Velcro apart,” says study author John P. Porcari, Ph.D. “You can damage cross bridges in muscle fibers that allow them to contract and generate force.”
To properly roll out, “slowly work the entire length of the muscle, exerting as much force as you can tolerate; it generates friction, which builds heat, making the muscle more pliable.”