The effect of translational and rotational traction on lower extremity joint loading

Previous studies have linked footwear traction to lower extremity non-contact injury; however, these studies mainly focussed on rotational traction exclusively. While studies have shown that increases in traction lead to increases in joint loading, represented by joint moments, these studies failed to determine how the individual components of rotational and translational traction affect joint loading. Therefore, this study investigated how each component of traction independently affects lower extremity joint loading. Traction testing was performed using a robotic testing machine on three shoes that had independent alterations of translational and rotational traction. All testing was conducted on a sample piece of artificial turf. Kinematic and kinetic data were then collected on 10 athletes performing two cutting movements in each shoe condition. As rotational and translational traction were independently altered, decreased rotational traction led to significant decreases in transverse and frontal plane joint loading at the ankle and knee joints, while increases in translational traction led to increases in frontal plane joint loading at the ankle and knee joints. Increases in joint loading in the transverse and frontal planes are one of the possible mechanisms of lower extremity non-contact injury. Both translational and rotational traction can independently alter the joint loading.