Indirect determination of maximal aerobic power output during work with one or two limbs

The cardiac frequency (f H ) and oxygen intake ( $$\dot V_{O_2 } $$ ) responses to submaximal and maximal work with 1- and 2-arms and 1- and 2-legs on suitably modified bicycle ergometers in relation to the prediction of maximal aerobic power output ( $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ ) have been examined in 12 healthy male subjects. The results showed that the physiological responses to the different forms of submaximal and maximal exercise were distinct and dependent upon the effective muscle mass used to perform the work. The observed $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ of 1-limb could be converted to respective 2-limb value with a coefficient of variation ranging from 4 to 7%, but maximal work with the arms gave no guide to that of the legs. Extrapolation of the $$\dot V_{O_2 } $$ /f H curve to the f H max in 1-leg (175 beats/min) and 2-arm (165 beats/min) resulted in an overestimation of $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ of +70 ± 200 ml · min−1 and +70 ± 240 ml · min−1; but in 1-arm work (153 beats/min), $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ was underestimated by −70 ± 270 ml · min−1. The bias in predictions for the 3 forms of exercise could be removed by applying the appropriate regression equations relating predicted to observed $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ , but the overall accuracy of the extrapolation method was limited to ± 8%, ± 15% and ± 23% in 1-leg, 2-arm and 1-arm work respectively. It was concluded that maximal work with the upper and lower limbs should be treated separately and if an accuracy of greater than ± 8 to ± 23% is required in situations where through injury, two limb exercise cannot be performed, attempts should be made to ascertain the $$\dot V_{{\text{O}}_{{\text{2max}}} }$$ of a single limb directly.