Findings: Signal abnormality is present within the region of the ischial tuberosity and long the expected location of the hamstring muscles consistent with complete rupture of the hamstrings at their tendinous origins. Signal abnormality is present within the muscle bellies of the semimembranosus, semitendinosus and proximal biceps femoris muscle consistent with partial tear and hematoma. Edema is also seen within the gluteus maximus and adductor muscles.

Diagnosis: Complete rupture of the hamstring tendons at their ischial origins. Partial tear and hematoma involving the semimembranosus, semitendinosus and proximal biceps femoris muscles. Edema within the gluteus maximus and adductor muscles.

Discussion: Hamstring muscle injuries are common in many sports, especially those requiring bursts of speed or rapid acceleration. Most complete hamstring ruptures are due to laceration or direct blows. Complete hamstring ruptures caused by indirect trauma (water-skiing injury) are quite uncommon.

Factors predisposing to hamstring injury include: muscle weakness, muscle imbalance inflexibility and steroid use.

Musculotendinous ruptures are much more likely if there is some intrinsic pathologic abnormality.

McMaster found that health musculotendinous units will not rupture through the tendon, but at the musculotendinous junction, the belly of the muscle, or at the bone tendon junction. Garrett relates the rapid force production of type II fibers and the susceptibility of these two-joint muscles to large extrinsic forces, to the occurrence of hamstring injuries.

Reference:
Blasier R and Morawa L. Complete Rupture of the Hamstring
Origin From a Water Skiing Injury. American Journal of Sports
Medicine, 1990 July-Aug;18(4):435-437.

Grace N. Water Skiing Hazards: Nature and Prevention.
Journal of Sports Medicine, 1974 July-Aug; 2(4):212-216.

Hummell G and Gainor BJ. Water-skiing-Related Injuries.
American Journal of Sports Medicine. 1982 July-Aug; 10(4):215-218.

Palmer WE, et al. MR Imaging of Myotendinous Strain. AJR,
1999 Sept;173(3).

Sallay P, et al. Hamstring Muscle Injuries Among Water Skiers.
American Journal of Sports Medicine. 1996 Apr; 24(2):130-136.

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