Hamstring Strain Ultrasound Case Series: Semitendinosus Injuries Dominant in NCAA Division I Athletes

Previous studies of acute hamstring strains have reported injury to the biceps femoris and semitendinosus in 50–100% and 0–30% of cases, respectively. This retrospective case series of hamstring injuries in Division I collegiate athletes exhibits an injury pattern on ultrasound imaging that differs from what would be expected based on prior literature. We examined ultrasound images of 38 athletes with acute hamstring strains for injury location (proximal muscle, proximal myotendinous junction, mid-portion of muscle, distal muscle) and affected muscles (biceps femoris, semitendinosus, or semimembranosus). 26 athletes (68.4%) injured the semitendinosus, and 9 athletes (23.7%) injured the biceps femoris long head. The majority (23, 60.5%) of athletes injured the proximal portion of the muscle or myotendinous junction. Though this study has many limitations, it demonstrates more frequent involvement of the semitendinosus and less frequent involvement of the biceps femoris than previously reported in the literature.