Article

The ZeroG provides dynamic body weight support (BWS) using a harness while
individuals with mobility impairments (e.g., spinal cord injury) ambulate
overground. Muscle activity during locomotion using this device was studied in 13
nondisabled adults (age 23.8 +/- 2.7 yr). Electromyography (EMG) recordings were
collected from tibialis anterior (TA), medial gastrocnemius (MG), rectus femoris
(RF), and biceps femoris muscles during randomized walking trials at preferred
speeds under five levels of BWS (0%, 20%, 40%, 60%, 80%). Filtered EMG signals
from each trial were normalized to 0% BWS and correlated with gait phases. Muscle
activity, averaged across muscles, decreased significantly at heel strike by
33.4% with increasing BWS. Offloading significantly decreased heel strike
activity of RF (62.8%), MG (35.5%), and TA (25.9%). Gait cycle completion time
increased with BWS primarily because of increased swing phase time. These results
summarizing the effect of BWS on muscle activation during ambulation can now be
compared with clinical populations using the ZeroG.

Langue : ANGLAIS