The jury is still out on the debate over stretching as a means of preventing hamstring injuries. There is some evidence that prolonged, daily stretching can help prevent injuries. It’s the quick, 10-second before activity stretching that doesn’t seem to really benefit athletes. And most of the studies have been done on athletes, so we really don’t have any data based on gender (male versus female) or age (younger versus older) or other factors.
The fact that stretching helps people feel good shouldn’t be discounted. Any movement improves circulation to the muscles (and joints) and has value in that alone. Stretching helps maintain full, pain free motion as well as improve posture and these are believed to be important factors in injury prevention.
Right now, the available evidence points to the use of exercises that emphasize eccentric muscle contractions as the best way to prevent hamstring injuries. Eccentric exercise starts with the muscle at its most shortened position (fully contracted) and then slowly releases the muscle to its fullest lengthened position.
Other suggestions for a prevention program include improving neuromuscular control of the entire lower half of the body. This includes core training to stabilize the lumbopelvic area, postural exercises to stabilize the trunk — especially while running or moving, and movements like high stepping, explosive starts, and forward-falling running drills.
More research is really needed to fully identify ways to prevent hamstring injuries. Perhaps there is an optimal way to stretch the muscle. Eccentric training is one way to balance out the strength component. There may be other methods equally important. Physical therapists are focusing on this problem and conducting specific research to help predict who is at risk for hamstring injuries, why, and what to do to prevent it from happening.