Zeller, B. L., McCrory, J. L., Kibler, W. B., & Uhl, T. L. (2003). Differences in kinematics and electromyographic activity between men and women during the single-legged squat. The American Journal of Sports Medicine, 31, 449-456.

Intercollegiate athletes (M = 9; F = 9) were filmed and analyzed performing five single-legged squats on the dominant leg.

Females demonstrated significantly more ankle dorsiflexion, ankle pronation, hip adduction and flexion, hip external rotation, and less trunk lateral flexion than males. Females also had greater muscle activation. This biomechanical phenomenon indicates females tend to position their entire lower extremity and activate muscles in a manner that could increase strain on the anterior cruciate ligament.

Implication. Because of different and less efficient leg position in stressful squat movements, females are more likely to have ACL injuries than males.

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