Muscle Activity During Lateral And Forward Locomotion With Body Weight Support

A change in environment (e.g., body weight support (BWS)) may be an important factor that determines self-selected movement patterns of locomotion. Not only forward and backward locomotion, but also lateral locomotion has been included in exercise programs. This study represents the first attempt to investigate the self-selected movement patterns of lateral locomotion at different BWS levels. PURPOSE: The primary purpose of this study was to investigate muscle activity during lateral and forward locomotion with BWS at individual’s self-selected speed. METHODS: Nine participants (23.0 ± 3.1 years) performed lateral and forward locomotion on a lower body positive pressure treadmill at 0%BWS, 20%BWS, and 50%BWS conditions at mode-specific preferred speed (PS). We measured mode-specific PS. Furthermore, we measured muscle activity (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) and preferred stride frequency (PSF) during the tests. Muscle activity, PS, and PSF were analyzed using a 2 (directions) x 3 (BWS) repeated measures analysis of variance (α = 0.05). RESULTS: Muscle activity (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius) and PSF were not influenced by the interaction of direction and BWS (P > 0.05). Muscle activity (rectus femoris, biceps femoris, tibialis anterior) and PSF were different between BWS conditions (P < 0.05). Rectus femoris muscle activity and PSF were different between directions (P < 0.01). During lateral locomotion, rectus femoris muscle activity was 15.1% ~ 41.1% lower (P < 0.01) than that of forward locomotion, regardless of BWS. Furthermore, PSF during lateral locomotion was 20.4% ~ 31.6% higher than that of forward locomotion, regardless of BWS (e.g., 103.4 strides/min and 80.7 strides/min for lateral and forward locomotion at 0%BWS, respectively: P < 0.001). PS was influenced by the interaction of direction and BWS (P < 0.05). PS during lateral locomotion was 38.4% ~ 51.8% lower than that of forward locomotion in all BWS conditions (P < 0.001). CONCLUSION: Individuals may change their locomotion speed and stride frequency to induce similar muscle activity (biceps femoris, tibialis anterior, gastrocnemius) during lateral and forward locomotion at self-selected pace, regardless of BWS. Supported by JSPS Grant Number 20 K11336