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Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion

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posted on 10.07.2019 by Ida E. Clark, Anni Vanhatalo, Christopher Thompson, Charlotte Joseph, Matt I. Black, Jamie R. Blackwell, Lee J. Wylie, Rachel Tan, Stephen Bailey, Brad W. Wilkins, Brett S. Kirby, Andrew M. Jones
We tested the hypotheses that the parameters of the power-duration relationship, estimated as the end-test power (EP) and work done above EP (WEP) during a 3-min all-out exercise test (3MT), would be reduced progressively after 40 min, 80 min, and 2 h of heavy-intensity cycling and that carbohydrate (CHO) ingestion would attenuate the reduction in EP and WEP. Sixteen participants completed a 3MT without prior exercise (control), immediately after 40 min, 80 min, and 2 h of heavy-intensity exercise while consuming a placebo beverage, and also after 2 h of heavy-intensity exercise while consuming a CHO supplement (60 g/h CHO). There was no difference in EP measured without prior exercise (260 ± 37 W) compared with EP after 40 min (268 ± 39 W) or 80 min (260 ± 40 W) of heavy-intensity exercise; however, after 2 h EP was 9% lower compared with control (236 ± 47 W; P < 0.05). There was no difference in WEP measured without prior exercise (17.9 ± 3.3 kJ) compared with after 40 min of heavy-intensity exercise (16.1 ± 3.3 kJ), but WEP was lower (P < 0.05) than control after 80 min (14.7 ± 2.9 kJ) and 2 h (13.8 ± 2.7 kJ). Compared with placebo, CHO ingestion negated the reduction of EP following 2 h of heavy-intensity exercise (254 ± 49 W) but had no effect on WEP (13.5 ± 3.4 kJ). These results reveal a different time course for the deterioration of EP and WEP during prolonged endurance exercise and indicate that EP is sensitive to CHO availability.

History

School

  • Sport, Exercise and Health Sciences

Published in

Journal of Applied Physiology

Volume

127

Issue

3

Pages

726 - 736

Citation

CLARK, I.E. ... et al, 2019. Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion. Journal of Applied Physiology, 127 (3), pp.726-736.

Publisher

American Physiological Society

Version

AM (Accepted Manuscript)

Rights holder

© American Physiological Society

Publisher statement

This paper was accepted for publication in the journal Journal of Applied Physiology and the definitive published version is available at https://doi.org/10.1152/japplphysiol.00207.2019.

Acceptance date

09/07/2019

Publication date

2019-09-01

Copyright date

2019

ISSN

8750-7587

eISSN

1522-1601

Language

en

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