| Abstrakt: |
The purpose of this study was to examine a new method for calculating the O2deficit that considered the O2uptake (V˙o2) kinetics during exercise as two separate phases in light of previous research in which it was shown that the traditional O2deficit calculation overestimated the recovery O2consumption (ROC). Eight subjects completed exercise transitions between unloaded cycling and 25% (heavy, H) or 50% (very heavy, VH) of the difference between the lactic acid threshold (LAT) and peakV˙o2for 8 min. The O2deficit, calculated in the traditional manner, was significantly greater than the measured ROC for both above-LAT exercises: 4.03 ± 1.01 vs. 2.63 ± 0.80 (SD) liters for VH and 2.36 ± 0.91 vs. 1.74 ± 0.63 liters for H for the O2deficit vs. ROC (P< 0.05). When the kinetics were viewed as two separate components with independent onsets, the calculated O2deficit (2.89 ± 0.79 and 1.71 ± 0.70 liters for VH and H, respectively) was not different from the measured ROC (P< 0.05). Subjects also performed the same work rate for only 3 min. These data, from bouts terminated before the slow component could contribute appreciably to the overallV˙o2response, show that the O2requirement during the transition is less than the final steady state for the work rate, as evidenced by symmetry between the O2deficit and ROC. This new method of calculating the O2deficit more closely reflects the expected O2deficit-ROC relationship (i.e., ROC ≥ O2deficit). Therefore, estimation of the O2deficit during heavy exercise transitions should consider the slow component ofV˙o2as an additional deficit component with delayed onset. |
