Muscle Strain Injuries: Research Findings and Clinical Applicability

Donald T. Kirkendall, PhD, William E. Garrett Jr., MD, PhD, University of North Carolina Department of Orthopaedics, Chapel Hill, NC.

In This Article


One of the most common injuries seen in the office of the practicing physician is muscle strain. Until recently, there were little data available on the basic science and its clinical application for the treatment and prevention of muscle strains. Studies in the last 10 years represent follow-up to investigations of muscle strain injuries from the laboratory and clinical settings.

Studies from the laboratory indicate that certain muscles (muscles that cross multiple joints or have complex architecture) are most susceptible to strain injury and have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone; they are produced by excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is very close to the muscle-tendon junction. Following injury, the muscle is weaker and is at risk for further injury. The force output of the muscle eventually returns while the muscle undertakes a predictable progression toward tissue healing.

Current imaging studies have been used to document the muscle-tendon junction as the site of injury. The most commonly injured muscles include the hamstrings, the rectus femoris, the gastrocnemius, and the adductor longus. Injuries inconsistent with the involvement of a single muscle-tendon junction proved to be located at tendinous origins rather than within the muscle belly. Injuries associated with a poor prognosis have been identified as potential candidates for surgery. These include injuries to the rectus femoris, the hamstring origin, and the abdominal wall.

Management techniques of common muscle injuries are available from sports organizations and have been described in the literature, and the risks of re-injury have been documented. Early efficacy and potential for long-term risks of nonsteroidal anti-inflammatory agents have been described as well.

New data demonstrate the beneficial effects of warm-up, temperature, and stretching on the mechanical properties of muscle, potentially reducing the risk of strain injury to the muscle. Fortunately, many of the factors protecting muscle, such as strength, endurance, and flexibility are also essential to the muscle's maximum performance. Future studies are intended to delineate the repair and recovery process, emphasizing not only the recovery of function, but also the susceptibility to re-injury during the recovery phase.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: