The influence of trunk forward inclination on knee biomechanics and myoelectricity during sidestep cutting

BACKGROUND: Trunk motion control may be an important factor affecting the risk of anterior cruciate ligament (ACL) injury by changing knee joint load during dynamic motion, there has been few studies investigating the influence of it on knee joint during sidestep cutting currently, and it has not been studied whether asymmetry between the dominant and non-dominant lower limbs in different trunk motion states during sidestep cutting. The objective of this study was to identify the leg laterality during sidestep cutting in trunk forward inclination state and to explore whether trunk forward inclination could reduce ACL injury risk.METHODS: Twenty healthy male college basketball athletes volunteered for this study. Each individual is required to complete sidestep cutting tasks in four states. They performed sidestep cutting using the dominant and non-dominant side with trunk forward inclination or natural position, respectively. Biomechanical testing equipment were used to synchronously collect knee biomechanics and myoelectricity data. A two-way (trunk motion x support side) ANOVA was used to analyze the influence of trunk motion control on knee biomechanics and myoelectricity and leg laterality.RESULTS: There was no leg laterality during sidestep cutting with trunk forward inclination state. During sidestep cutting with trunk forward inclination state, the knee flexion angle at initial contact (P=0.003 for the dominant side; P=0.011 for the non-dominant side), knee peak flexion angle (P=0.001 for the dominant side; P=0.000 for the non dominant side) and H/Q ratio (P=0.048 for the dominant side) were significantly greater than trunk natural state.CONCLUSIONS: There was no leg laterality during sidestep cutting in trunk forward inclination state, and the trunk forward state may have a protective effect on the ACL during sidestep cutting, especially for the dominant side.