Contract the Antagonist Muscle Before Stretching
To increase range of motion, contract the muscle opposite the one being stretched before repeating the stretch. Examples: for hamstrings, contract the quadriceps as hard as possible for 5–15 seconds, ideally 10 seconds; if needed, increase to 20–30 seconds. Pointing the toe back toward the shin can help contract harder. For triceps stretching, contract the biceps during the overhead triceps stretch. For quadriceps tightness, contract the hamstrings intensely for 10–30 seconds by bringing the heel toward the glutes, then relax and repeat the quadriceps stretch.
“I'd like you to contract your quadriceps as hard as you possibly can for about five to 15 seconds. Let's say 10 seconds... And then now, go ahead and repeat that stretch where you're trying to touch your toes or touch the floor... What most of you will find is that you have an immediate increase in hamstring flexibility or your range of motion has increased.”