The effect of changing toe direction on knee kinematics during drop vertical jump: a possible risk factor for anterior cruciate ligament injury

Purpose The purpose of this study was to examine the effect of changing toe direction on knee kinetics and kinematics associated with anterior cruciate ligament injury during drop vertical jumps. Methods Fourteen females performed drop vertical jumps under three toe conditions (natural, toe‐in, and toe‐out). The knee kinetics and kinematics during landing were evaluated using a motion analysis system. Results under three toe conditions were compared using a one‐way repeated measures analysis of variance and a post hoc Bonferroni test. Results Toe‐in landing was associated with a significantly greater knee abduction angle, tibial internal rotation angle, and knee abduction moment than the natural and toe‐out conditions. Toe‐out landing was associated with significantly greater tibial internal rotational angular velocity. Conclusions Changing toe direction significantly affects knee kinetics and kinematics during landing. It is important to avoid changing toe direction excessively inward or outward during landing to prevent the increases in knee abduction and tibial internal rotation which might increase the risk of ACL injury. Level of evidence Prognosis, Level IV.