Prior Upper Body Exercise Reduces Critical Power Derived Using the 3-min All-Out Test

Abstract

PURPOSE: Prior upper body exercise reduces work capacity (W′) but does not change critical power (CP) when the power-duration relationship is evaluated using the conventional method comprising a series of fixed work-rate cycling tests performed to the limit of tolerance. CP and W′ may also be derived using a 3-min all-out test. If this test provides valid estimates of CP and W′ the parameters should be affected by prior upper body exercise similarly to those derived by the conventional method. Therefore, this study examined the effects of prior upper body exercise on CP and W′ derived using the 3-min all-out cycling test. METHODS: Seven trained male cyclists (VO2peak: 63 ± 4 mL/kg/min) performed two 3-min all-out cycling tests. CP was calculated as the average power output over the last 30 s of the all-out effort, and W′ was calculated as the power-time integral above CP. All-out tests were preceded by 3 min unloaded pedalling and performed without (CYC) and with (ARM-CYC) prior high-intensity upper body exercise comprising eight 1 min arm-cranking exercise bouts, separated by 30 s rest intervals, at an intensity of 1.5-2.0 W/kg body mass. In ARM-CYC the unloaded pedalling began 1 min after the final arm-cranking bout. Participants performed familiarization trials of both CYC and ARM-CYC. RESULTS: CP was lower in ARM-CYC (312 ± 49 W) than CYC (358 ± 54 W) (P < 0.01), whereas W′ in ARM-CYC (15.3 ± 3.5 kJ) was not different from CYC (13.8 ± 3.2 kJ) (P = 0.09). Blood pH was lower in ARM-CYC than CYC immediately before (7.244 ± 0.035 vs. 7.370 ± 0.035, P < 0.01) and after (7.098 ± 0.078 vs. 7.150 ± 0.086, P = 0.03) the 3-min all-out effort. Blood plasma lactate concentration was higher in ARM-CYC than CYC immediately before (14.3 ± 3.9 vs. 1.8 ± 0.4 mmol/L, P < 0.01) and after (21.3 ± 4.2 vs. 14.3 ± 4.4 mmol/L, P < 0.01) the 3-min all-out effort. VO2peak during the 3-min all-out effort was lower in ARM-CYC (57 ± 5 mL/kg/min) than CYC (60 ± 6 mL/kg/min) (P = 0.01). Heart rate at the end of the 3-min all-out effort was higher during ARM-CYC (174 ± 9 bpm) than CYC (167 ± 10 bpm) (P < 0.01). CONCLUSION: The effects of prior upper body exercise on CP and W′ differ depending on whether the parameters are determined using the 3-min all-out test or the conventional method. Therefore, the physiological determinants of CP and W′ derived using the two methods may not be equival