Investigation on the kinetic and kinematic characteristics of knee and ankle joints during simulated downhill walking: Implication for ACL injury risk

Abstract

We investigated 3D kinematic and kinetic changes of knee and ankle during downhill walking as the slope angle increased and evaluated biomechanical injury risk factors related to non-contact ACL injury. Fifteen male subjects performed level walking and 15A degrees and 25A degrees downhill walking. For the kinetic and kinematic parameters, one-way ANOVA and post-hoc tests were performed at a significance level of 0.05. This study revealed significant differences in 3D knee and ankle kinematics and kinetics among 0A degrees, 15A degrees and 25A degrees downhill walking. The peak posterior ground reaction force, the peak knee anterior force and the knee valgus moment (0A degrees vs. 15A degrees: p < 0.05; 0A degrees vs. 25A degrees: p < 0.05) in the early stance phase increased as the slope angle increased. The peak knee internal tibial rotation moments in the late stance also increased (0A degrees vs. 15A degrees: p < 0.05; 0A degrees vs. 25A degrees: p < 0.05; 15A degrees and 25A degrees: p < 0.05) as the slope angle increased. These results showed the risk for ACL injuries may be increased during downhill walking with a greater slope angle.