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The purpose of this study was to determine the relationship between actual time to exhaustion or time limit (ATLIM) during bicycle ergometry and predicted time to exhaustion (PTLIM from the Critical Power (CP) test Fourteen males (x¯ ± SD = 22·36 ± 2·13 years) volunteered as subjects for this investigation. The subjects visited the laboratory on seven occasions separated by at least 24 h. The first two visits were used for the determination of CP; during the remaining sessions the subjects rode a Monarch bicycle ergometer at power loadings of CP — 20%, CP, CP + 20%, CP + 40% and CP + 60% for the determination of ATLIM. Theoretically, power loadings les;CP can be maintained indefinitely without exhaustion and the PTLIM for power loadings > CP can be estimated from the results of the CP test. The accuracy of the CP test for estimating the time to exhasution during bicycle ergometry was determined by comparing ATLIM to PTLIM using correlation coefficients, standard error of estimates and related t-tests. The results of this study indicated that there were no significant (p > 0·05) differences between ATLIM and PTLIM for power loadings > CP (ATLIM vs PTLIM at CP + 20% = 8·19 ± 3·90 vs 7·13 ± 2·69min, t = 2·106, r =0·893, SEE = l·21min; CP + 40% = 3·60 ± 1·37 vs 3·46 ± 1·18min, t = 0·842, r = 0·882, SEE = 0·556min; CP + 60% = 2·36 ± 0·95 vs 2·32 ± 0·79min; t = 0·328 r = 0·841, SEE = 0·428min). Power curve analyses however, indicated that the CP test overestimated the power loading which could be maintained for 60 min by a mean of approximately 17%. [ABSTRACT FROM PUBLISHER]

Presently available tests of physical working capacity (PWC) such as [Vdot]O2max and critical power may not be appropriate for unfit subjects because they require maximal or supramaximal workloads. Therefore, the purpose of this study was to evaluate a submaximal discontinuous incremental bicycle ergometer test (PWCFT) with an end point (fatigue threshold) determined by recording electromyographic (EMG) fatigue curves in the quadriceps muscle. The fatigue threshold was defined as the lowest workload producing a slope of the EMG voltage-time relation that was significantly different from zero slope at p<0.05 (single tail). The test-re-test reproducibility of PWCFT (n=17 subjects) was found to be r = 0.947, with no significant difference between trials. Thirty-two healthy male subjects aged 18-29 (mean 23-4 ± 31 years) whose fitness levels ranged from highly trained to untrained sedentary level were tested for PWCFT, lactate threshold (OBLA), percentage heart rate range at PWCFT (%HRR), and heart rate-workload relation (HR-WL). Stepwise multiple regression resulted in R = 0.833 with %HRR accounting for 40.7%, OBLA for 22.8% and HR-WL for 5.9% of the total variance. In addition, 12 subjects performed critical power (CP) testing. PWCFT and CP were correlated at r=0.670 with no significant difference p<005) between the means for the two methods. The results of this study indicated that the PWCFT test was objective, valid and highly reproducible and particularly useful for evaluating the PWCFT of unfit subjects. [ABSTRACT FROM PUBLISHER]