Abstract

The aim of this study was to investigate whether any changes in the process of automatic postural control after maximal long-lasting exercise can be notoiced in high performance athletes. Seventy one male cyclists of high level fitness (aged x = 17 ± 1,4 years) volunteered to participate in the investigation. Mean (± SD) height and body mass were 178 ± 6,4 cm and 67,3 ± 7,9 kg respectively. All subjects (n = 71) completed a continuous, progressive bicycle ergometer ride. They started with the load of 10 N which was increased 10 N every 3 minutes until 70 N. External work was recorded during each single turn of the wheel of the ergometer. Subjects kept on riding until they were too fatigued to continue or the plateau of VO2 was reached despite the load increase. During the test oxygen uptake (VO2) [ml/kg/min], minute ventilation (VE) and heart rate (HR) were measured. Blood samples were analyzed for lactate (LA) and H+ ions concentrations. Before (TEST 1) and immediately after (TEST 2) maximal ergocycle test the postural dynamics of the centre of pressure (COP) was measured on a force platform during 32-s bipedal standing in normal position, feet side by side, with eyes open, eyes closed and in visual feedback. Mean velocity (VCOP), radius (RCOP), area (ACOP) and distance (DCOP) covered during the trial by the moving COP were reported. After the exercise sway values were significantly higher in tests both with eyes open and closed. In the present study no significant changes of COP excursion were observed in visual feedback test. The results showed that maximal long-lasting exercise affects postural stability negatively, especially during tests with eyes open and eyes closed. Verf.-Referat