The effect of footwear torsional stiffness on lower extremity kinematics and kinetics during lateral cutting movements

Purpose: Footwear torsional stiffness affects ankle kinematics during cutting movements. The influence of torsional stiffness on lower extremity kinetics has not been studied. It was hypothesised that footwear with high torsional stiffness increases the ankle eversion, knee abduction and internal rotation moments in cutting movements. Methods: Nineteen participants performed seven repetitions of a lateral jab and a shuffle cut in two shoes with different torsional stiffness. Markers placed on forefoot, rearfoot and shank of the right leg were used to determine the kinematics. Simultaneous recordings of the ground reaction forces allowed the calculation of ground reaction impulses and internal joint moments using an inverse dynamics approach. Results: Peak torsion angles (frontal plane rotation between fore-and rearfoot) were reduced in the torsional stiff shoe (shuffle cut: 22.0 degrees vs. 18.5 degrees, p < 0.001; lateral jab: 22.8 degrees vs. 20.1 degrees, p = 0.020 flexible vs. stiff shoe). For the shuffle cut, the peak ankle eversion moment (52.9 Nm vs. 63.0 Nm, p = 0.003) and inversion angle (25.9 degrees vs. 28.5 degrees, p < 0.001) were higher in the stiff shoe. For the lateral jab no differences between footwear were found for the ankle kinematics or kinetics. No differences between footwear were found for knee kinematics. The ground reaction impulses were not different between shoes. Conclusions: Increased footwear torsional stiffness causes higher ankle eversion moments which may increase the risk for ankle injuries. Knee moments were not affected by footwear torsional stiffness; therefore, footwear torsional stiffness seems to have no effect on the risk for anterior cruciate ligament (ACL) injuries.