Cardiopulmonary responses to exercise in swimmer using a swim bench and a leg-kicking ergometer.

Abstract

There are few studies on the relative cardiopulmonary demands of the arm-stroke and the leg-kicking action in swimmers, mainly because of the absence of a suitable dry-land ergometer. Therefore, the purpose of this study was to compare the cardiopulmonary responses to exercise using a swim bench and a leg-kicking ergometer. Twelve highly-trained male swimmers with mean age of 20.3 +/- 1.9 (yrs), stature 1.77 +/- 0.04 (m) and body mass of 73.7 +/- 3.3 (kg) gave written informed consent and performed two separate incremental exercise tests on subsequent days. These tests used either a swim bench for assessment of arm-stroke or a specially designed front crawl leg-kicking ergometer. Oxygen consumption (VO2), heart rate (HR) and exercise intensity were recorded throughout both exercise tests. Peak oxygen consumption (VO2peak), peak heart rate (HRpeak) and peak exercise intensity (EIpeak) were also recorded. Furthermore, the relationships between submaximal heart rate and exercise intensity (HR/EI) and between oxygen consumption and exercise intensity (VO2/EI) for arm or leg exercise were explored. Mean values for VO2peak, HRpeak and EIpeak for a arm-stroke and leg-kick respectively were; 3.22 +/- 0.31 vs 3.76 +/- 0.42 (1 x min(-1); P=0.02), 170 +/- 3 vs 176 +/- 3 (b x min(-1); P=0.07) and 124.2 +/- 9.4 vs 141.3 +/- 12.7 (watts; P=0.01). The mean VO2peak and EIpeak for arm-stroke represented 85% and 88% respectively of the same measures for leg-kick. The HR/EI and VO2/EI relationships were shown to be linear (at least r=0.94, P<0.05 and r=0.96; P<0.01 respectively) and the differences in the gradients and elevations of these relationships for arm-stroke vs leg-kick were significant (at least P<0.05; ANCOVA). These results show that highly-trained swimmers can achieve similar peak levels of oxygen consumption when using the arms or the legs. The ability to assess the cardiopulmonary responses to front-crawl arm-stroking and leg-kicking relative to exercise intensity might be useful in understanding the importance of the arm and leg components of whole body metabolism in swimmers, especially during training programmes.