The Influence of Horizontal Velocity on Inter-lower-limbs Local and Global Asymmetry During Walking

Purpose: Considering the influence of horizontal velocity on many biomechanical characteristics of walking, the purpose of this study was to investigate how inter-lower-limbs local and global asymmetry is influenced by changes in walking speed from slow to fast. Methods: Ground reaction force data and trajectory of attached markers of bilateral lower limbs of 15 right leg-dominant able-bodied males were collected at each of three walking velocity conditions (slow, normal, and fast). Walking step frequencies were controlled with a metronome. Principal Component Analysis (PCA) was performed on net sagittal joint moments of the stance phase to identify the actions of each joint and the lower limbs separately. Lower limb behavior was assumed symmetrical if the PCA curves extracted from each joint (local gait asymmetry) or each of the lower limbs (global gait asymmetry) described the same portion of the stance phase. Results: Based on findings, the PCA method highlighted different functional tasks for ankle, knee, and hip joints suggesting local gait asymmetry at slow, normal, and fast walking. Also, at slow walking speed, total lower limbs showed global gait asymmetry, however, for normal and fast walking speeds, results showed global gait symmetry. Conclusion: Considering the possibility of the effect of movement velocity on walking behavior, it is recommended that this factor should be controlled during walking investigations in clinical and research settings.