Influence Of Initial Metabolic Rate On The Parameters Of The 3-min All-out Cycling Test In Men

Abstract

PURPOSE: It has been established that a single 3 min all-out cycling test can be used to estimate the power asymptote (critical power; CP) and the curvature constant (W[[Unsupported Character - &#900;]]) of the hyperbolic power-duration relationship for severe intensity exercise. The CP represents the highest work rate that does not require the expenditure of the finite work capacity denoted by the W'; the latter is expended at a predictable rate >CP. It was hypothesized that when exercise performed immediately preceding the 3-min all-out test was performed <CP (moderate and heavy exercise), the CP and W' parameters would be unaffected, whereas preceding exercise of different durations >CP (severe exercise) would systematically reduce the W' without affecting the CP. METHODS: Seven physically active male subjects completed 3-min all-out cycling tests in randomized order on 5 occasions: with the test immediately preceded by unloaded cycling (control; C); 6-min moderate (M); 6-min heavy (H); 2-min severe (S2); or 4-min severe (S4) intensity exercise. The CP was estimated from the mean power output over the final 30 s of the test and the W[[Unsupported Character - &#900;]] was estimated as the power-time integral above end-test power. Data were analyzed using one-way ANOVA. RESULTS: There were no significant differences in the estimated CP between C (265 ± 69), M (275 ± 52 W), S2 (274 ± 55 W), or S4 (273 ± 65 W). However, the estimated CP following H (286 ± 66 W) was significantly elevated compared to C (P<0.05). The W[[Unsupported Character - &#900;]] was significantly lower (P<0.05) in S2 (11.5 ± 2.5 kJ) and S4 (8.9 ± 2.2 kJ) than in C (17.3 ± 3.1 kJ), M (17.2 ± 2.4 kJ) and H (15.6 ± 2.3 kJ). CONCLUSION: Consistent with our hypothesis, the W' was significantly reduced by prior severe-intensity exercise with the effect being greater for S4 compared to S2. However, while the CP was not different between the C, M, S2 and S4 conditions, it was significantly increased by preceding H exercise. These results are generally consistent with the predictions of the CP concept. The effects of prior H exercise on the parameters of the power-duration relationship warrant further investigation.