Muscle activation during body weight-supported locomotion while using the ZeroG

Area of Science:

• Biomechanics
• Neurorehabilitation
• Human Locomotion

Background:

• Dynamic body weight support (BWS) systems, like the ZeroG, assist individuals with mobility impairments during overground ambulation.
• Understanding the impact of BWS on muscle activity is crucial for optimizing rehabilitation strategies.

Purpose of the Study:

• To investigate the effects of varying levels of BWS on lower limb muscle activity during walking in nondisabled adults.
• To establish a baseline for comparing muscle activation patterns in clinical populations using BWS devices.

Main Methods:

• Electromyography (EMG) recorded from tibialis anterior, medial gastrocnemius, rectus femoris, and biceps femoris muscles.
• Participants walked at preferred speeds under five BWS conditions (0% to 80%).
• EMG data normalized to 0% BWS and analyzed across gait phases.

Main Results:

• Overall muscle activity at heel strike decreased significantly with increasing BWS (33.4% reduction).
• Specific muscles showed marked reductions in heel strike activity: rectus femoris (62.8%), medial gastrocnemius (35.5%), and tibialis anterior (25.9%).
• Gait cycle completion time increased with BWS, primarily due to an extended swing phase.

Conclusions:

• BWS significantly modulates muscle activation patterns during walking, reducing activity at heel strike.
• The findings provide a quantitative understanding of BWS effects on muscle function, essential for clinical applications.
• These results serve as a reference for future studies involving patients with mobility impairments using BWS technology.