Toe-in Landing Increases the Ankle Inversion Angle and Moment During Single-Leg Landing: Implications in the Prevention of Lateral Ankle Sprains.

CONTEXT: Identifying the foot positions that are vulnerable to lateral ankle sprains is important for injury prevention. The effects of foot position in the transverse plane on ankle biomechanics during landing are unknown.
OBJECTIVE: To examine the effects of toe-in or toe-out positioning on ankle inversion motion and moment during single-leg landing.
DESIGN: Repeated measures.
SETTING: Motion analysis laboratory. PARTICIPANTS: 18 healthy participants (9 men and 9 women).
INTERVENTIONS: Participants performed single-leg landing trials from a 30-cm high box under 3 conditions: natural landing, foot internally rotated (toe-in), and foot externally rotated (toe-out). MAIN OUTCOME MEASURES: 4 toe-in or toe-out angles were calculated against 4 reference coordinates (laboratory, pelvis, thigh, and shank) in the transverse plane. Ankle inversion angle, angular velocity, and external moment in the 200 ms after initial foot-to-ground contact were compared between the 3 landing conditions.
RESULTS: All toe-in or toe-out angles other than those calculated against the shank were significantly different between each of the 3 landing conditions (P < .001). Ankle inversion angle, angular velocity, and moment were highest during toe-in landings (P < .01), while eversion angle and moment were highest during toe-out landings (P < .001). The effect sizes of these differences were large. Vertical ground reaction forces were not different between the 3 landing conditions (P = .290).
CONCLUSIONS: Toe-in or toe-out positioning during single-leg landings impacts on ankle inversion and eversion motion and moment. Athletes could train not to land with the toe-in positioning to prevent lateral ankle sprains.