Cardiorespiratory and efficiency responses during arm and leg exercises with spontaneously chosen crank and pedal rates

The aim of this study was to compare the cardiorespiratory and efficiency responses between upper (T-UBE) and lower (T-LBE) body exercises at the same relative power outputs and with spontaneously chosen crank (SCCR) or pedal (SCPR) rates. Twelve participants performed exercise bouts set at 20, 40, 60 and 80% of maximal power (MP) separated by passive recovery periods. Oxygen uptake, ventilation, gross and work efficiencies during T-LBE were significantly (P<0.05) higher than during T-UBE. These results suggest that these responses were not directly related to the relative intensities. However, no significant difference was found for delta efficiency and heart rate values. During T-UBE and T-LBE, gross efficiency increased significantly (P<0.01) with power output. Delta and work efficiencies remained constant. They could be linked to the use of SCCR and SCPR, which increase in relation to power output. The testing procedure, i.e., the same percentage of MP for T-UBE and T-LBE and the same SCCR and SCPR could explain these results. The present results confirm that the cardiorespiratory and efficiency responses between arm and leg exercises are not always similar, although the power output are normalized in relation to NIP and add to the understanding of differences between upper and lower body.