Directions of single-leg landing affect multi-segment foot kinematics and dynamic postural stability in male collegiate soccer athletes

BACKGROUND Understanding lower limb kinematics and postural control in different directions of single-leg landings is critical to evaluate postural control and prevent lower limb injuries. However, foot and ankle kinematics and postural control during single-leg landings in different directions are less known. RESEARCH QUESTION Does the difference in the direction of single-leg landing affect the foot kinematics on the frontal plane and dynamic postural stability? METHODS A cross-sectional study was conducted. Forty-nine male collegiate soccer players performed single-leg forward (FL), 45° lateral (LL), and medial (ML) direction landings. The lower limb, foot (rearfoot, midfoot, forefoot), and ankle kinematics during an impact phase were evaluated, and a curve analysis was performed using a statistical parametric mapping method to compare the three landings. The three landings were compared in terms of postural control parameters, including time to stabilization (TTS), peak of ground reaction forces (GRFs), root-mean-square of the mediolateral GRFs for 0-0.4 s (GRFML0.4), loading rate, and magnitude of horizontal GRFs from 0-0.4 s (HGRF-0.4), 0.4-2.4 s (HGRF-2.4), and 3.0-5.0 s. RESULTS Ankle and rearfoot kinematics in LL exhibited smaller eversion and pronation positions than FL and ML (p < 0.01). The TTS-mediolateral (TTS-ML) was longer in the LL than in FL and ML (p < 0.001). The GRFML0.4, HGRF-0.4, and -2.4 in the LL and ML were greater than those in the FL (p < 0.001). SIGNIFICANCE Directions of single-leg landing affect foot and ankle kinematics and postural stability. Specifically, the LL exhibits more inverted ankle and supinated rearfoot positions, and longer TTS-ML. Thus, the LL may induce stretching of the lateral ankle ligament. These findings can help understand foot kinematics and assess dynamic postural control.