Energy Absorption Strategies in the Lower Extremities during Double-Leg Landings in Knee Valgus Alignment

Abstract

Landing with the knee in a valgus position may alter energy absorption strategies in the lower extremities and increase mechanical stress on the knee joint. We compared the energy absorption strategies in the lower extremities during valgus and varus landings. Seventeen females were divided into valgus and varus groups. Lower extremity kinetic data were obtained during drop jumps, using a three-dimensional motion analysis system. Negative mechanical work in the lower extremities were calculated during landing. The valgus group exhibited significantly more negative mechanical work at the knee, and less negative mechanical work at the hip, compared with the varus group. However, there was no difference in the negative mechanical work at the ankle between the two groups. Findings suggest that an increased valgus landing reduces the contribution of the hip to energy absorption and is associated with a reciprocal increased contribution by the knee. Hence a knee valgus landing position may be a key biomechanical factor that increases energy absorption in the knee, thereby increasing the risk of injury. Results further indicate that this can be prevented by adopting a knee varus position on landing, which facilitates absorption of the mechanical load at the hip, rather than at the knee.