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Physical Therapists Provide Commentary on Hamstring Injuries

What do high-speed runners, dancers, kick boxers, and rugby players all have in common? Hamstring injuries. The hamstring muscle along the back of the thigh is made up of three parts: semitendinosus, semimembranosus, and biceps femoris. Hamstring strains and tears can cause scar tissue that puts the athlete at risk for another injury. And often that second injury occurs within two weeks of returning to their sport after rest and recovery. And it's more severe and more disabling.

What's the problem here? Why are the hamstrings so susceptible to injury and reinjury? Physical therapists from the University of Wisconsin use the case of a high-speed runner to show with MRIs just how much hemorrhage, swelling, and scarring remain when the athlete returned to his sports participation. They propose ways to prevent these common injuries as well as a three-phase plan for rehabilitation of acute hamstring strain injuries.

In order to prevent musculoskeletal injuries like hamstring strains, it's important to identify any and all factors that put the athlete at increased risk for injury. Some of these risk factors are modifiable (can be changed) while others are nonmodifiable (can't be changed). Obviously, focusing on modifiable risk factors is the recommended approach.

Two main risk factors for hamstring injuries are age (older) and a past history of a hamstring strain. Not much the physical therapist can do about either of those! But a program of prevention and/or rehabilitation can address modifiable factors such as muscle weakness, lack of flexibility, and a strength imbalance between hamstrings and quadriceps muscles.

To begin, the therapist conducts an in-depth exam evaluating the patient's history (including the mechanism of injury or how it happened) and symptoms (location and severity of injury). Special tests are carried out to assess range-of-motion, strength, coordination, balance, and flexibility. The therapist also evaluates the surrounding muscles for any sign of injury, inflexibility, or imbalance.

X-rays aren't very useful in confirming a hamstring strain, tear, or rupture. Unless the tendon pulls a piece of bone away from its attachment, nothing will show up on the X-ray. MRIs are used instead because they show deep portions of the muscle, scarring from a previous injury, and location/severity of the injury (partial or complete rupture). The surgeon can use this information when deciding if surgery is necessary. Complete ruptures with tendon retraction almost always need surgical repair, especially in the athletic population.

The injured athlete is usually most interested in one thing: how long before I can go back to my sports training and/or competition? MRIs help answer that question by giving information that can be used to estimate time to recovery, which translates into time away from sports participation.

Injury location and severity are the main markers for prognosis. For example, recovery takes longer when the free tendon (nearest the attachment to the bone) is injured compared with injury to the portion of the tendon closest to the muscle (intramuscular tendon).

Patient symptoms such as pain, tenderness to palpation, loss of motion, and weakness aren't always the best indicators. For example, intramuscular tendons tend to be the most symptomatic yet heal the fastest. Complete ruptures requiring surgery can be painless.

Once it's decided that a rehab program is the ticket, then what? The goal is to get the athlete back to his or her level of performance prior to the injury with the least risk possible of reinjury. Studies show that there are several key ingredients needed in the rehab program to accomplish this. One is to focus on eccentric (lengthening) muscle contractions while working on flexibility during the early healing phase. Another is to include training to improve coordination of the lumbopelvic (low back and pelvis) region. And a third is the need to include neural mobilization (nerve sliding and gliding) techniques for the sciatic nerve that runs down through the hamstring muscle.

For anyone interested, the authors provide a detailed description of each phase of rehab for hamstring recovery. Online videos are available demonstrating each exercise. For each of the three phases (Phase 1, 2, and 3), suggestions are made for protection of the injured and now healing hamstrings as well as proper use of nonsteroidal antiinflammatory medicine during the early phases of recovery. Goals for each phase are also provided.

Phase 1 starts with low-intensity, pain free exercises designed to minimize pain and reduce edema while helping form a nice, clean linear scar. The hamstrings are not stretched in order to avoid a thick scar and even contraction of the hamstrings is limited to painfree motions to encourage muscle healing. All exercises prescribed during this period must protect the muscle while it is remodeling during this early healing phase.

The athlete is slowly progressed from phase one to phase two. Fiber repair is still an important phase of recovery during this portion of the rehab process. The hamstrings are not yet lengthened to their end range until strength is restored. Exercises are done that will gradually lengthen the muscle and overstretching is avoided. When full strength is present without pain and there is full motion, then phase three can begin. In this final phase, the focus is on fine-tuning everything needed for return-to-sport.

Specific exercises to help the athlete return-to-sport and the best timing for introducing that phase of rehab are suggested. The athlete will need to work on agility, sport-specific drills, and quick directional and postural changes. Muscle testing is done by the therapist to determine when the athlete is ready to progress to this last phase of rehab. They must have enough strength and stability to carry loads required by repetitive motion and needed to carry out those motions with speed. In order to return to full sports participation, they must have full strength and motion without pain and function near maximal speeds without pain.

What about prevention? What do these researchers have to say that can help athletes prevent this injury in the first place and avoid a reinjury once it does happen? Most athletes stretch their hamstring muscles thinking this will prevent injuries. But studies don't really support hamstring stretching as a very effective method for injury prevention. Instead, there is evidence that eccentric (lengthening) hamstring exercises may be the best way to avoid this type of injury.

How is this done? First, evaluate each athlete for risk factors that can be changed and work on changing them. Then, instead of working on knee flexion to strengthen the hamstrings (that's a concentric or shortening contraction), the hamstrings are put in their shortest (already contracted) position and slowly lengthened (e.g., moving from hip extension and knee flexion to hip flexion and knee extension). Eccentric training should be done during the pre-season period as well as during the sports season.

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.

The authors tell us that there is a lack of evidence to support the current rehab programs in place. Sports and orthopedic physical therapists are concentrating their focus on evidence to support specific exercises and rehab programs for athletes with hamstring injuries. More research is also needed to predict risk of reinjury, identify when athletes can return to their sport safely, and determine prognosis.


Bryan C. Heiderscheit, PT, PhD, et al. Hamstring Strain Injuries: Recommendations for Diagnosis, Rehabilitation, and Injury Prevention. In Journal of Orthopaedic & Sports Physical Therapy. February 2010. Vol. 40. No. 2. Pp. 67-81.

02/18/2010

*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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