Functional gait asymmetry in able-bodied subjects

Symmetry is assumed in unilateral gait studies or when pooling right and left limb data. The purpose of this study was to identify which muscle powers and associated mechanical energies were related to the support and propulsion functions using Principal Component Analysis (PCA). Nineteen able-bodied male subjects participated in this study. They were all right-hand and leg dominant. Simultaneous bilateral three-dimensional data were collected from an eight-camera video system and two force plates. The PCA method was used to reduce and categorize the peak muscle powers and mechanical energies calculated at the hip, knee and ankle in each plane. Student's t-test for paired data was applied to determine significant differences between the identified gait parameters. The limb which had a propulsion function was characterized by a strong third hip power at push off. Most of the parameters identified by the PCA were associated with the hip, and were mainly in the sagittal plane. These parameters were concentrated during push-off. There was a secondary support function which occurred during midstance. For the limb having a supporting function, most of its activities were associated with the knee, and were spread throughout the stance phase.