VO2max responses in separate and combined arm and leg air-braked ergometer exercise

Using an air-braked cycle ergometer, we sought to determine the relative contributions of the arms and legs in eliciting the maximal O2 uptake (VO2max). Ten healthy, non-arm-trained males did progressive exercise to exhaustion on the ergometer instrumented to partition the push-pull arm exercise from the cycling leg exercise. Exercise was done with arms only (100% arms), legs only (100% legs, with arms at sides), and in combinations of 10% arms/90% legs, 20% arms/80% legs, and 30% arms/70% legs. To approximate conventional bicycling, four subjects exercised to exhaustion doing leg cycling on the air-braked ergometer with the hands fixed to stationary bars. The maximal power output and VO2max were not significantly different (P greater than 0.05) for the 10% arms/90% legs and the 20% arms/80% legs combinations. Maximal power output and VO2max for 10% arms/90% legs was significantly greater than that for the 100% arms, 100% legs, and 30% arms/70% legs regimens (P less than 0.05). The highest VO2max measured in combined arm/leg exercise for four subjects using 10% arms/90% legs (N = 3) or 20% arms/80% legs (N = 1) was not significantly different from that measured in air-braked ergometer leg cycling with hands fixed to stationary bars (P greater than 0.05). We conclude that push-pull arm exercise of 10 or 20%, combined with leg cycling of 90 or 80%, respectively, or leg cycling with hands fixed to bars optimize the arm/leg contributions in eliciting VO2max. These findings suggest that the upper-body stabilizing effort in conventional cycling (legs cycling, hands fixed) contributes approximately 10-20% to inducing VO2max.