Article

The present study focuses on the role of superficial abdominal muscles revealed
by electromyographic recordings during the maintenance of a bipedal stance
perturbed by post-exercise hyperventilation. Twelve healthy subjects performed
six 30-s postural tests: one pre-exercise test while breathing quietly, then one
test every minute for the 5 min immediately following a maximum-intensity,
incremental cycling exercise test. Displacement of the centre of pressure in the
sagittal plane was monitored over time. Myoelectric activities of the obliquus
externus (OE), obliquus internus (OI) and rectus abdominis (RA) muscles were
recorded by surface electromyography (EMG). Metabolic parameters were measured
with a portable telemetric device. The change in ventilatory drive induced by
exercise was accompanied by a significant increase in both postural sway
parameters and EMG activities. For OE and OI, the increased EMG activities were
prominent during expiration, whereas OI was silent during inspiration. OE and RA
were activated during both expiration and inspiration. It is concluded that the
compensation of respiratory disturbances of the erect posture appears to be less
effective when minute ventilation increases. The patterns of muscle activity
suggest that abdominal muscles are controlled differentially and that their
functional coordination is dependent on the respiratory demand.
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Langue : ANGLAIS