The effect of exhausting aerobic exercise on the timing of anticipatory postural adjustments

Aim. The aim of the study was to investigate the influence of exhausting aerobic exercise on the timing of anticipatory postural adjustments (APAs). Methods. The APAs of 12 participants were recorded at baseline, after a VO(2)max running test, and again following a 45-min rest period. APAs were induced using a rapid bilateral arm-raising maneuver, and were analyzed in the rectus abdominis, hamstring group, gluteal group, and lumbar and thoracic paraspinal muscles using electromyography. Postural stability was assessed by monitoring anterior/posterior displacement of the center of pressure using a force plate. We hypothesized that APA onset would be ear lier following exhausting aerobic exercise as compared to the baseline measures, but that this effect would be transient (i.e., APA onset following the rest period would not differ from that at baseline). Results. Exhausting aerobic exercise resulted in a significantly earlier APA in one of the 5 muscles evaluated, the thoracic paraspinal group, and this effect persisted 45-min postexercise. Exhausting aerobic exercise did not affect postural stability during the rapid arm-raising maneuver. Conclusion. The findings lend tentative support for the notion that earlier APAs constitute a functional adaptation by the motor system to maintain postural stability in the presence of fatigue.