Bailey_16PM1 (a) Manuscript (ACT 3-min) (3) Accepted.pdf (220.89 kB)
Download file

Acetaminophen ingestion improves muscle activation and performance during a 3-min all-out cycling test

Download (220.89 kB)
journal contribution
posted on 02.10.2018, 13:27 by Paul T. Morgan, Anni Vanhatalo, Joanna L. Bowtell, Andrew M. Jones, Stephen BaileyStephen Bailey
Purpose: Acute acetaminophen (ACT) ingestion has been shown to enhance cycling time-trial performance. The purpose of this study was to assess whether ACT ingestion enhances muscle activation and critical power (CP) during maximal cycling exercise. Methods: Sixteen active male participants completed two 3-min all-out tests against a fixed resistance on an electronically-braked cycle ergometer 60 minutes following ingestion of 1 g ACT or placebo (maltodextrin, PL). CP was estimated as the mean power output over the final 30 s of the test and W′ (the curvature constant of the power-duration relationship) was estimated as the work done above CP. The femoral nerve was stimulated every 30 s to measure membrane excitability (M-wave) and surface electromyography (EMGRMS) was recorded continuously to infer muscle activation. Results: Compared to PL, ACT ingestion increased CP (ACT: 297 ± 32 vs PL: 288 ± 31 W, P<0.001) and total work done (ACT: 66.4 ± 6.5 vs PL: 65.4 ± 6.4 kJ, P=0.03) without impacting Wˈ (ACT: 13.1 ± 2.9 vs PL: 13.6 ± 2.4 kJ, P=0.19) or the M-wave amplitude (P=0.66) during the 3-min all-out cycling test. Normalized EMGRMS amplitude declined throughout the 3-min protocol in both PL and ACT conditions; however, the decline in EMGRMS was attenuated in the ACT condition, with the EMGRMS amplitude being greater compared to PL over the last 60 s of the test (P=0.04). Conclusion: These findings indicate that acute ACT ingestion might increase performance and CP during maximal cycling exercise by enhancing muscle activation.



  • Sport, Exercise and Health Sciences

Published in

Applied Physiology, Nutrition, and Metabolism


MORGAN, P.T. ... et al., 2018. Acetaminophen ingestion improves muscle activation and performance during a 3-min all-out cycling test. Applied Physiology, Nutrition, and Metabolism, 44 (4), pp.434–442.


© The Authors. Published by NRC Research Press


AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at:

Acceptance date


Publication date



This paper was accepted for publication in the journal Applied Physiology, Nutrition, and Metabolism and the definitive published version is available at