Abstract
This study compared the physiological responses and the mechanical efficiency during both arm cranking exercise and leg pedaling exercise with identical work loads, and determined whether arm cranking or unilateral leg pedaling performance could be used to estimate bilateral pedaling exercise capacity. Seven healthy adult males [mean age: 32 (27-36) years old] participated in this study. Arm cranking and leg pedaling exercise tests were carried out using an identical electrically controlled bicycle ergometer. The cranking/pedaling rate was set at 60 rpm. Exercise was performed under the following conditions: Bilateral leg pedaling (BLP), Unilateral leg pedaling (ULP), Bilateral arm cranking (BAC), and Unilateral arm cranking (UAC). By ramp load protocol in gradually increasing 20 W/min stages, peak oxygen uptake (peak VO2) and peak heart rate (peak HR) were obtained using BLP, ULP, BAC, and UAC. The oxygen uptake and heart rate obtained using BLP, ULP, BAC, and UAC were compared under three exercise work loads (20 W, 40 W, 60 W). In comparison with ULP and UAC, the values of peak VO2 and peak HR in BLP and BAC were high, and the response to the 20 W to 60 W exercise intensities rose in tandem with work load. Differences in physiological response due to disparities in the exerted muscle mass became large and showed a rising trend, particularly in ULP and UAC. There were no significant correlations between BLP and the other types of exercise (BAC, ULP, UAC) in peak VO2 and peak HR. In conclusion, the physiological responses in bilateral and unilateral arm/leg exercise at an identical work load depend on the amount of muscle mass exerted. It is hard to estimate the aerobic work capacity (peak VO2) using BLP from the results of exercise performed with BAC, ULP, and UAC.
