$\dot VO_2$ peak during free swimming using the backward extrapolation of the O₂ recovery curve

Summary

The purpose of this study was to evaluate the accuracy and feasibility of estimating oxygen consumption ($\dot VO_2$) during maximal swimming by using the backward extrapolation (BE) of the$\dot VO_2$ recovery curve to time zero. Two series of experiments were conducted. In the first, the validity of the BE method was ascertained by comparing the$\dot VO_2$ peak values obtained during free swimming (Douglas bag technique) with those estimated by the BE method during recovery after the same tests. These results were also compared with$\dot VO_2$ peak measured during uphill treatmill running.$\dot VO_2$ peak measured during maximal free swimming and estimated by the BE method during the recovery period of that test, were not significantly different. No significant difference was found between$\dot VO_2$ peak uphill treadmill running and free swimming. In the second series of experiments,$\dot VO_2$ peak was measured in each of 28 swimmers during uphill running (conventional method) and during unimpeded swimming using the BE method. The mean value was significantly higher during swimming ($\overline X$3.37) than during running ($\overline X$3.23). Seventy-five percent of the subjects had higher$\dot VO_2$ peak during swimming. The swimming speed during maximal swimming effort was 10% higher when the BE method was used then when the same subjects were tested by the conventional Douglas bag technique. The BE method is a reliable and valid way to measure$\dot VO_2$ peak in maximal swimming and allows the swimmer to use his specifically trained musculature fully.