Effect of prior heavy arm and leg exercise on VO2 kinetics during heavy leg exercise

The aim of the present study was to examine the effect of prior exercise at a remote site on the VO(2) kinetics during subsequent heavy cycle exercise using a model that allowed us to discriminate between the VO(2) fast and slow component responses. Ten male subjects completed a constant-load exercise of 6 min cycling at 90% of the VO(2)peak in three conditions: without prior exercise (LE-C), after heavy cycling exercise (6 min at 90% of the VO(2)peak) (LE-L) and after heavy arm-cranking exercise (6 min at 90% of the arm VO(2)peak) (LE-A). Subjects performed four repetitions of each exercise protocol, separated by at least 1 day. VO(2) was measured on a breath-by-breath basis and VO(2) kinetics were determined with a biexponential model. There were no significant differences in the VO(2) fast component parameters between LE-C, LE-L and LE-A. However, the VO(2) slow component amplitude was significantly reduced in LE-L and LE-A compared to LE-C, but the reduction was less pronounced in LE-A [the value of the VO(2) slow exponential term at the end of exercise, A(2)', was 657 (SD 200) ml x min(-1) in LE-C versus 384 (SD 136) ml x min(-1) in LE-L and 551 (SD 169) m x min(-1) in LE-A; P<0.05]. The results of this study demonstrate that prior heavy arm exercise alters VO(2) kinetics during cycling exercise by reducing the VO(2)slow component amplitude, though this reduction is smaller than the reduction observed following prior heavy leg exercise. These data indicate that the primary factor causing changes in the VO(2) kinetics is probably located in the involved muscle.