Resumen de Prior Upper Body Exercise Reduces Cycling Work Capacity but Not Critical Power.
Michael a. Johnson, Graham R. Sharpe, Dean E. Mills, Peter I. Brown
AB Purpose: This study examined whether metabolite accumulation, induced by prior upper body exercise, affected the power-duration relationship for leg cycle ergometry. Methods: Seven males performed, to the limit of tolerance and both without (L) and with (AL) prior severe-intensity arm-cranking exercise, an incremental cycling test and four constant power cycling tests to determine the parameters of the power-duration relationship: critical power (CP) and W'. Results: At the onset of cycling exercise plasma lactate (L vs AL: 1.2 +/- 0.1 vs 11.6 +/- 2.9 mEq[middle dot]L-1) and hydrogen ion (40.4 +/- 1.3 vs 53.1 +/- 4.3 nEq[middle dot]L-1), concentrations were higher during AL compared with L, whereas the strong ion difference (37.8 +/- 1.8 vs 32.4 +/- 2.0 mEq[middle dot]L-1) and bicarbonate concentration (25.7 +/- 0.7 vs 18.3 +/- 1.9 mEq[middle dot]L-1) were lower during AL compared with L (P < 0.01). During incremental exercise, maximum cycling power (358 +/- 15 vs 332 +/- 21 W) and peak oxygen uptake (V[spacing dot above]O2peak) (4.31 +/- 0.36 vs 3.71 +/- 0.44 L[middle dot]min-1) were lower during AL compared with L (P < 0.05). The rate of increase in plasma potassium concentration during constant power cycling was greater during AL compared with L (0.09 +/- 0.08 vs 0.14 +/- 0.13 mEq[middle dot]L-1[middle dot]min-1) (P < 0.05), and exercise duration was 35 +/- 15% shorter (P < 0.01). CP was not different between L and AL (267 +/- 19 vs 264 +/- 20 W), whereas W' was lower in AL (17.3 +/- 5.7 vs 11.8 +/- 4.2 kJ) (P < 0.01). Conclusion: The reduced W' after prior upper body exercise indicates that the magnitude of W' is partly dependent on metabolite accumulation.
