Effects of Ankle Immobilization on Lower Extremity Joint Coupling Variability

Human movement is a complex system that encompasses several factors within the body to create coordination. It is not fully understood how the many degrees of freedom (DOF) of the body organize to create movement. Both internal and external influence how the DOF problem works to produce varying movement goals. The purpose of this study was to better understand the organization patterns of the body by eliminating a DOF. The ankle joint was immobilized to determine if there were differences at the hip and knee joint couplings. It was hypothesized that there would be an increase in movement variability at the hip and knee joints when the ankle was immobilized compared with normal gait. Joint kinematics have shown that the AFO effectively immobilized the ankle joint by decreasing plantarflexion throughout the gait cycle and restricting ankle inversion/eversion and internal/external rotation. There were also changes seen at the hip and knee joints. Hip flexion decreased and adduction increased through the gait cycle. Internal rotation of the hip decreased in stance and increased during swing phase. There was a decrease in knee extension and adduction during stance phase and an increase in internal rotation during swing. There were no significant changes in coordination variability in any of the nine couplings compared. Further experiments need to be conducted to better understand human movement patterns.