The effect of stage duration on the calculation of peak VO2 during cycle ergometry.

This study investigated the influence of stage duration on the calculation of peak oxygen consumption (peak VO2 to determine whether both the lactate threshold (LT) and peak VO2 could be measured during the same test without compromising the peak VO2 value obtained. Eight moderately-active females (mean age +/- SD = 19.6 +/- 2.5 years) performed three peak VO2 tests on an electrically-braked cycle ergometer. Power output was increased every minute for the short peak VO2 test (S) and every three minutes for the long peak VO2 tests (L). Testing took place over two weeks with all tests separated by at least 48 hours. The first peak VO2 test was a long test (L1) and served as familiarisation. The subjects then performed a short (S) and a long (L2) peak VO2 test in random, counterbalanced order. For each subject, all three tests were performed at the same time of day in controlled environmental conditions. There was no significant difference between the two exercise protocols for peak VO2 when expressed in ml x kg(-1) x min(-1) (F[1,7]=3.47, P=0.105) or in L x min(-1) (F[1,7]=3.39. P=0.108). However, the maximum heart rate (HRmax) achieved in S was significantly less than the HRmax achieved in L2 (F[1,7]=33.4, P<0.001). The power output at exhaustion (Wpeak) was significantly greater in S than in L2 (F[1,7]=56.5, P<0.001). The data from this study therefore showed that in moderately-active females, a three-minute incremental protocol, allowing for the simultaneous calculation of the LT, could be used without compromising peak VO2, but that HRmax and Wpeak were affected.