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

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 (V over dot O-2), heart rate (HR) and exercise intensity were recorded throughout both exercise tests. Peak oxygen consumption (V over dot O-2 peak), 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 (V over dot O-2/EI) for arm or leg exercise were explored. Mean Values for V over dot O-2 peak, HRpeak and EIpeak for a arm-stroke and leg-kick respectively were; 3.22 +/- 0.31 vs 3.76 +/- 0.42 (I.min(-1); P=0.02), 170 +/- 3 vs 176 +/- 3 (b.min(-1);P=0.07) and 124.2 +/- 9.4 vs 141.3 +/- 12.7 (watts; P=0.01).The mean V over dot O-2 peak and EIpeak for arm-stroke respresented 85% and 88% respectively of the same measures for leg-kick. The HR/EI and V over dot O-2/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.