Injury Breakdown: Getting A Handle On Hamstrings
By Abby Sims
It came as no surprise to me that Darrelle Revis exited yesterday's game against the Patriots early in the second quarter having aggravated his left hamstring. Revis played limited time in last Thursday's practice and was listed as probable for Sunday, though reports had him moving well. Evidently Revis and the team's medical staff felt his hamstring wouldn't limit his range, and he was cleared to start. This is a cautionary tale however – hamstring injuries just don't resolve in a matter of days, especially so when an athlete is required to jump, leap, run and cut with abandon.
Though I didn't evaluate Revis, those who did evidently felt he had rebounded sufficiently from the mild strain (listed as "tightness") he had complained of. And though that may have appeared to be the case, why test such a nagging type injury for a player deemed to be so important, so early in the season? And this after missing camp – though I presume, giving him the benefit of the doubt, that Revis did train independently while playing hard-to-get with management. If I am giving him too much credit, shame on him… he asked for this. The Jets however, did not.
Andy Pettitte, though older and with a history of muscle strains, is our current local example of the sometimes arduous process of recovery from this type of injury. Pettitte reportedly had a grade I strain (the mildest version), though his was in the groin (adductor) muscles, which are clearly stressed during the pitching motion. Pettitte had been out of action since July 18th and, though he was initially expected to return to the lineup by mid August, he did not start until yesterday, working six innings in an excellent no-decision game against Baltimore. The Yankees eventually lost the game, but Pettitte's successful return is good news for the Yankees as they head into the playoffs.
What are the hamstrings and what do they do?
The hamstrings are a group of muscles in the back of the thigh that run from the boney prominence at the bottom of the pelvis (the sit bone, or ischial tuberosity) to just below the knee. Two of the three hamstring muscles attach at the inner (medial) tibia, and the third (which has two sections, or heads) has multiple attachments, primarily into the outer (lateral) side just below the knee at the fibular head, but also into muscles and ligaments of the outer compartment. The tibia is the larger and innermost bone of the lower leg, while the fibula is the thinner outer bone (it is the tibia which forms the knee joint with the femur of the thigh).
The hamstrings act to bend (flex) the knee and also work to extend the hip (bringing the thigh behind the plane of the hip). However, they do not act as the primary movers to do both of these motions simultaneously.
Studies have shown that the hamstrings also act during the last degrees of knee extension (straightening). While the quadriceps (the muscles in the front of the thigh) act to straighten the knee, the hamstrings contract – pulling the tibia backward. This helps to prevent excessive extension (hyperextension). You may recall from a prior blog entry that anterior cruciate ligament (ACL) injuries result from traumatic hyperextension. The hamstrings are recruited to help to prevent ACL tears, providing some level of dynamic stabilization.
During the gait cycle (walking) the hamstrings act to decelerate (slow down) the forward swing of the leg. By doing so they help to control the position of the foot when the heel strikes the ground. If the knee is unable to straighten all the way, possibly because of a contracture of the hamstrings, the foot will strike in more of a flat position, changing the way forces are sent up through the chain of the lower extremity. This could cause undue stress on muscles and joints up through that chain.
Why is hamstring tightness such a big deal?
Tight hamstrings can cause a variety of problems due to the excessive pull of the muscles on their attachments. Poor posture and alignment are among the end results. Excessive tightness rotates the pelvis backward, and can cause the spine to be too arched in the low back (lumbar spine) or too rounded in the mid back (thoracic spine). Studies on those with unstable segments in the lumbar spine have found that a significant percentage have particularly tight hamstrings (See Wheeless' Textbook of Orthopaedics). Tight hamstrings can also alter a person's gait pattern (the way he or she walks) and influence the way we sit – tight hams prevent sitting with the knees extended unless the back is rounded forward to compensate.
As with other tight muscles, lack of hamstring flexibility prevents the muscles from acting as efficiently to absorb shock, thereby transmitting more force to the joints and predisposing to injury. In addition, sports that require significant hamstring flexibility will likely lead to traumatic strains if the limit of stretch of the muscle is exceeded during play. Remember, a muscle strain comes in three basic varieties, the most involved of which (Grade III) is actually a complete tear.
Can hamstring strains be prevented?
Stretching in order to improve flexibility and warming up to prior to doing so can be very helpful in minimizing the risk of hamstring strains. Stretching has been getting a bad rap in the media lately with studies pointing out that warm-up stretching does not prevent injury. That may very well be the case. However, and it is a very BIG however, in my opinion, being flexible is vital to maintaining musculoskeletal health and minimize overall risk of injury.
Sufficient strength and endurance of the muscles, both as hip extenders (with the knee straight) and as knee flexors is important to prevent injury. Much has also been said about the need to train the muscles both concentrically (contracting/shortening against resistance) and eccentrically (lengthening contractions that occur with the resisted release of a contraction). Working creatively to include various methods of hamstring strengthening can be instrumental to preventing injury.
Unfortunately, participating in sports sometimes entails making plays that push a muscle to (or beyond) its limit. The baseball player who almost does a split to make a big catch, or the NY Jet who defends Randy Moss as he attempts an acrobatic one-handed catch in the end-zone just may strain a hamstring…
Abby Sims is an orthopedic and sports physical therapist who has been in private practice in NYC for the past 30 years (you may be familiar with her husband, sportscaster & WFAN alum Dave Sims). Abby has a Masters of Science in Physical Therapy from Duke University and has extensive experience working with professional, collegiate and recreational athletes with musculoskeletal injuries – both non-operative and operative. She has also enjoyed lecturing at many medical conferences. Abby looks forward to responding to your questions or writing about topics that you suggest. For more information about Abby, or her practice, please check out www.RecoveryPT.com as well as www.AthletiSense.com.
