Postural control and stepping kinematics of multidirectional gait initiation

Abstract

Background: Understanding the anticipatory postural adjustments (APA) and stepping characteristics associated with gait initiation (GI) has enhanced the approaches used for gait rehabilitation, the design of adaptive devices, and the development of fall prevention programs. However, previous studies have primarily concentrated on forward GI. Therefore, the movement characteristics of multidirectional GI, which is common in daily activities and sports, remain unknown. Purpose: This study aimed to investigate the APA parameters and stepping kinematics of healthy young adults when performing multidirectional GI with the effect of an obstacle (presence versus absence) and stepping leg (right versus left). Methods: Fourteen right-leg dominant young adults (Female: N = 7; age: 22.4 ± 2.4) performed five trials of GI at their comfortable pace. Experimental conditions included legs, obstacle (a 15cm-height hurdle), and directions (forward: F00, lateral: L90, medial 45 degrees: M45, lateral 45 degrees: L45). Repeated Measure ANOVAs (directions, obstacle, legs as within factors) with Bonferroni post hoc were used to assess the statistical significance. Results: APA duration and mediolateral (ML), anteroposterior(AP) COP displacement decreased as the stepping direction shifted laterally from F00 to L90. Similar pattern of change was observed in the COP velocity metrics. Step distance decreased as the laterality increased from M45 to L90, yet the step durations remained consistent throughout directions in GI without an obstacle. Step variability was the greatest in L90. The presence of an obstacle significantly increased ML COP displacement, step distance, step duration, step velocity, and step variability. On average, the dominant leg stepping had longer APA duration and step duration, while the ML COP velocity in the APA phase were slower in all stepping directions. Significance: These findings demonstrate the unique characters of multidirectional GI and provide clinical relevance to the improvement of the movement versatility of gait rehabilitation programs for individuals recovering from lower limb impairments.