OXYGEN DEFICITS INCURRED DURING 45-S, 60-S, 75-S AND 90-S MAXIMAL CYCLING ON AN AIR-BRAKED ERGOMETER

The aims of this study were to determine the most appropriate duration for the measurement of the maximal accumulated O2 deficit (MAOD), which is analogous to the anaerobic capacity, to ascertain the effects of mass, fat free mass (FFM), leg volume (V(leg)) and lower body volume (V(lb)) on anaerobic test performance, to examine the reproducibility for peak power output (W(peak)) or maximal anaerobic power using an air-braked cycle ergometer and to produce approximations for the percentages of aerobic and anaerobic metabolism during exercise of short duration but high intensity. A group of 12 endurance trained cyclists [mean age 25.1 (SD 4.6) years; mean body mass 73.43 (SD 7.12) kg; mean maximal oxygen consumption 5.12 (SD 0.35) 1-min-1; mean body fat 12.5 (SD 4.1) %] accordingly performed four counterbalanced treatments of 45, 60, 75 and 90 s of maximal cycling on an air-braked ergometer. The mean 02 deficit of 3.521 for the 45-s treatment was significantly less (P < 0.01) than those for the 60 (3.75 1), 75 (3.80 1) and 90-s (3.75 1) treatments. These data therefore indicate that in predominantly aerobically trained subjects the 02 deficit attains a plateau after 60 s of maximal cycling on an air-braked ergometer. Statistically significant interclass correlation coefficients (P<0.05) between the anthropometric variables (mass, FFM, V(leg) and V(lb)) and W(peak) or maximal anaerobic power (0.624-0.748) and MAOD (ml) or anaerobic capacity (0.666-0.772) furthermore would suggest the relevance of taking into account muscle mass during anaerobic tests. Intraclass correlation coefficients (0.935-0.946; all P<0.001) would indicate a high degree of reliability for the measurement of W(peak). The relative importance of anaerobic work decreased from 60% for the 45-s test to 40% for the 90-s one. Hence our study showed that both aerobic and anaerobic metabolism contributed significantly during all-out tests of 45-90 s duration.