Endurance fitness and blood lactate concentration during stepping exercise in untrained subjects

The purpose of the present study was to explore the possibility that reference blood lactate concentrations, determined during stepping exercise, could be used to derive an index of endurance fitness. The traditional measure of endurance fitness, maximal oxygen uptake (VO2max) and the individual relationships between blood lactate concentration and submaximal VO2 were determined during stepping for 10 untrained males. VO2 max values were 48.7 +/- 5.1 ml.kg-1.min-1 (mean +/- sd). The time to exhaustion during stepping at 80 per cent VO2 max (38.82 +/- 17.83 min) provided an additional measure of endurance fitness. The per cent VO2 max at a blood lactate concentration of 4 mM was correlated significantly with endurance time (rho = 0.75, P less than 0.05). These results show that a submaximal step test can be used to determine oxygen uptake and per cent VO2 max at a reference blood lactate concentration. However, for this group of subjects, per cent VO2 max at a blood lactate concentration of 4 mM showed only a modest correlation with endurance.