Article

This study investigated how the recruitment patterns of shoulder muscles were
influenced by wheelchair propulsion speed. Electromyography (EMG)
activity of
seven muscles was recorded with surface electrodes on 15 nondisabled subjects
during wheelchair propulsion on a stationary ergometer.
Kinetic data were
measured by a SmartWheel. EMG total intensities were calculated to describe the
muscle activation level, while the angles formed by first principal component and
second principal component loading scores were calculated to describe the
spectral content of EMG signals. Significant differences were observed in kinetic
variables between the two testing speeds (p < 0.05). The EMG intensity of the
tested muscles increased significantly with increased speed (p < 0.05). The push
muscles showed a longer EMG duration, whereas the recovery muscles exhibited
significantly earlier EMG onset and peak activities at the fast speed. The
smaller angle values in the fast propulsion speed indicated that faster motor
units were recruited to match the mechanical requirement for the faster motion.
Pushing a manual wheelchair at a faster speed not only requires a higher level of
propulsive muscle activity but also a higher level of recovery muscle activation.

Langue : ANGLAIS