High anaerobic energy release during submaximal arm exercise.

The anaerobic energy release during submaximal arm (AE) and leg exercise (LE) has been estimated from O2 deficit measured at the onset of exercise. Eight male subjects were studied during 8-10 min of arm or leg cycling at the same relative workload (53% of the peak exercise-induced increase in pulmonary oxygen uptake, VO2). The workloads were 78 +/- 4 W during AE and 173 +/- 11 W during LE and VO2 was 1.51 +/- 0.06 1 min-1 for AE and 2.33 +/- 0.15 1 min-1 for LE. The half-time of the VO2 on-response was considerably longer (P < 0.01) during AE (62 +/- 9 s) than during LE (33 +/- 4 s) and the peak blood lactate concentration was higher (P < 0.05) during AE (4.8 +/- 0.5 mmol.l-1) than during LE (3.5 +/- 0.4 mmol.l-1). Oxygen deficit was 1.64 +/- 0.16 and 1.78 +/- 0.16 1 for AE and LE respectively. Oxygen deficit was higher during AE than during LE when related to absolute workload (P < 0.01), or to VO2 at steady state (P < 0.001) or to limb volume (P < 0.001). The proportion of the total energy demand covered by anaerobic energy release at the onset of exercise (0-8 min) was about 54% higher (P < 0.01) during AE than during LE. It is concluded that the energy release to a greater extend is covered by anaerobic processes during AE than during LE.