Foot Toe-out Landing Reduces Anterior Talofibular Ligament And Calcaneofibular Ligament Strain During Simulated Ankle Sprain

PURPOSE: Lateral ankle sprain frequently occurs during landing, injuring the anterior talofibular (ATFL) and calcaneofibular ligaments (CFL). Previous studies usually used indirect indicators, such as inversion angle, as an injury risk indicator, but epidemiological support is lacking. This study innovatively uses a three-dimensional multi-body foot model to quantify ankle sprain risk by calculating ligament strains. It suggests that landing with foot toe-out may reduce the ATFL and CFL strains. A three-dimensional multi-body foot model was used to calculate ATFL and CFL strains during a drop-landing to investigate whether increasing the foot toe-out angle would reduce the risk of inversion sprains during landing. METHODS: Thirty-five high sports demand participants (15 males and 20 females, age: 21.0 ± 0.9 years, height: 176.2 ± 8.8 cm, body mass: 71.6 ± 12.8 kg) were recruited to perform a drop-landing test using a trapdoor device to simulate ankle inversion sprains. Two landing conditions were tested, i.e., natural landing (NL) and toe-out landing (TL). Kinematic data were collected using a twelve-camera motion analysis system, the strain of ATFL and CFL were calculated using a three-dimensional rigid-body foot model. RESULTS: From NL to TL conditions, the ATFL strain decreased (NL = 3.57 ± 1.92 %, TL = 0.36 ± 1.18 %, p < 0.001, Cohen’s d = 2.01), as was the CFL strain (NL = 1.38 ± 1.80 %, TL = -0.28 ± 2.29 %, p = 0.003, Cohen’s d = 0.81). CONCLUSION: Increasing foot toe-out angle reduces ATFL and CFL strains during drop-landing with ankle inversion, thereby reducing the potential of lateral ankle sprains.