Ventilatory and circulatory responses at the onset of voluntary exercise and passive movement in sprinters

The purpose of this study was to clarify the characteristics of ventilatory and circulatory responses at the onset of voluntary exercise and passive movement in sprinters. Eleven male university sprinters and 11 male untrained subjects participated in the present study. Voluntary exercise consisted of leg extension-flexion movement for 20 s with weights corresponding to 5% of each subject's body mass attached to each ankle. Passive movement was achieved without weights by the experimenter alternately pulling ropes that were connected to the subject's ankles for the same period and frequency as during voluntary exercise. In the present study, the following results were found: (1) the magnitude of relative changes (gain) of minute ventilation at the onset of passive movement in the sprinters was significantly smaller than that in the untrained subjects [mean (SEM) 33.3 (2.9) vs 61.7 (6.4)%, P<0.05]; (2) the time for reaching one-half of the gain (response time) of heart rate at the onset of voluntary exercise and passive movement in the sprinters was significantly slower than that in the untrained subjects [2.5 (0.2) vs 1.7 (0.2) s in voluntary exercise and 3.4 (0.8) vs 1.5 (0.1) s in passive movement, P<0.05]; (3) the gain and response time of mean blood pressure at the onset of voluntary exercise and passive movement showed no significant differences between the two groups. It is concluded that sprinters show slowed heart rate response at the onset of voluntary exercise, and attenuated ventilatory and slowed heart rate responses at the onset of passive movement as compared with untrained subjects.