Q: I pulled a hamstring muscle last season (I play college football). We are about to start spring training and I'm worried it might happen again. Is there anything I can do to avoid this?
A: It is good to pay attention to previous or old hamstring injuries. Without being overly pessimistic, you should know that studies do show that athletes who have injured their hamstring tendon or muscle are twice as likely to reinjure the same tendon/muscle. The older you are and the more you weigh, the higher the risk for a hamstring tear. But weak hamstrings, imbalance in leg muscle strength, and tight hip flexors also increase the risk of a hamstring strain.
What can be done to help athletes like yourself get back to their sports or other desired athletic activities? The first thing NOT to do is stretch the acutely injured tissue. With the hamstrings (a muscle all athletes spend time stretching), stretching after an acute injury only lengthens the time it takes to get back into action. It sounds like you are past the acute phase so supervised stretching may have a place in your rehab program.
In the acute phase, stretching does not seem to lengthen muscle fibers during healing. Scar tissue forms as part of the natural healing process. And that scar tissue links up with muscle fibers causing stiffness in the tendon-muscle unit. Researchers are still looking for better ways to lengthen injured/healing hamstring tissue.
In the meantime, studies show it makes much more sense to focus on core training, which will increase trunk stabilization and greatly reduce the risk of reinjury. Agility training is another valuable approach in preventing hamstring reinjury. Eccentric training (starting with the muscle contracted and in a shortened position and moving into positions of elongating the tissue) has some benefit but remains under investigation.
There is evidence that reinjury is greatly reduced when a program of agility and trunk stabilization is completed (compared with traditional rehabilitation with hamstring stretching and strengthening). One test that has proven reliable in predicting safe return to activity is called the active hamstring flexibility test. The athlete lies on his or her back with one leg in a knee extension splint. The splinted leg is quickly lifted up off the table as far as it will go.
The test is done on both legs. The amount of hip flexion is measured and compared from side-to-side. Equal movement without pain or apprehension in the presence of normal hamstring strength is a good sign the athlete is ready to return to the field or stage. You may want to ask your coach, athletic trainer, or Physical Therapist to test you before resuming full sports activity.
Reference: Marc Sherry, PT, DPT, LAT, CSCS. Evaluation and Treatment of Acute Hamstring Strains and Related Injuries. In Sports Health. March/April 2012. Vol. 4. No. 2. Pp. 107-114.
