Background Biomechanical studies have shown that female athletes have significantly increased dynamic knee valgus during drop landing and cutting tasks. However, the relationship between static leg and foot alignment and dynamic knee valgus is not well understood.

Objective To determine the relationship between leg and foot alignment and dynamic knee valgus during single-leg squat, single-leg drop landing and cutting tasks.

Design Controlled study.

Setting University laboratory.

Participants 50 female collegiate athletes (mean age 20.0 ± 1.3 years; height 159.6 ± 5.8 cm; weight 55.1 ± 6.3 kg).

Interventions Participants performed single-leg squat, single-leg drop landing and cutting tasks, and kinematic data regarding knee valgus alignment were collected using a high-speed video camera.

Main outcome measurement Leg and foot alignment including thigh-transmalleolar angle (an indicator of tibial torsion), leg-heel angle and navicular drop test scores were measured, and correlation coefficients between these parameters and knee valgus alignment were analyzed using Spearman's rank correlation and an unpaired t-test.

Results The thigh-transmalleolar angle was significantly and positively correlated with knee valgus rate in single-leg squat and drop landing tasks (Spearman's rank correlation coefficient=0.360, p=0.012 and 0.414, p=0.004, respectively). The navicular drop test score and leg-heel angle were not significantly correlated with knee valgus rate in each task.

Conclusion Tibial torsion is related to dynamic knee valgus alignment during squatting and landing tasks and its measurement and evaluation through the thigh-transmalleolar angle might be useful as a pre-participation screening test to prevent injury among female athletes.