Effects of maximal oxygen uptake test and prolonged cycle ergometer exercise on the quiet standing control

This work aims at testing the influence of peripheral and central fatigue, after maximal oxygen uptake test (Test1) and prolonged (Test2) cycle ergometer exercises, respectively, on sway density curve (SDC) parameters of postural control. Sixteen healthy male subjects were submitted to stabilometric tests, before and after the exercises. The Test1 was started at 12.5W, with 12.5W/min increments and 50rpm cadence until exhaustion. From the respiratory gas exchange signals, the first ventilatory threshold was obtained by the v-slope method. After a minimum of 72h, the subjects performed the Test2 for 60min, at a power output corresponding to 70% of such threshold. Before and just after these exercises, a set of 10 stabilometric trials of 50s was performed, alternating the eyes open and closed conditions, intercalated by a 10s resting period. The resulting signals were used to obtain the SDC. The Test1 caused decrease of the mean of peaks duration in SDC (p<0.05), decreasing the stability level, with small changes in the rates of central nervous system (CNS) and muscular torque controls. Conversely, Test2 increased the mean of time intervals between peaks in SDC (p<0.05), thus decreasing the CNS commands rate with minor changes in the stability level. Visual privation had a greater effect on body sway than these exercises, which were applied to muscles that are not the main actuators in body sway control. Concluding, this study allowed discriminating the effects of exercise intensities on body sway control.