Contributions of lower-limb muscle power in gait of people without impairments

Background and Purpose. Although gait asymmetry in rehabilitation has been documented, little is known about propulsion and control tasks performed by each limb and how these casks are managed between the lower limbs. The pur pose of this study was to test the hypothesis that the leading limb contrib utes mainly to forward progression, whereas the trailing limb provides cont rol and propels the lower limb to a lesser extent. Subjects. Nineteen men w ith an average age of 26.2 years (SD=3.2, range=21-34) and no history of or thopedic ailments participated in the study. Methods. Muscle power was dete rmined using an a-camera high-speed video system synchronized with 2 force plates. The principal-component analysis method was applied to reduce and c lassify 52 gait variables for each limb, and Pearson correlations were used to determine the interactions within the data sets for each limb. Results. Gait propulsion was initiated by the hip of the leading limb shortly after heel-strike and was maintained throughout the stance phase. Control was th e main task of the trailing limb, as evidenced by the power absorption burs ts at the hip and knee. Conclusion and Discussion. Within-limb interaction further emphasized the functional relationship between forward progression and control tasks and high-lighted the importance of frontal- and transvers e-plane actions during gait.