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Eccentric Exercise-Induced Muscle Damage Reduces Gross Efficiency

Lookup NU author(s): Dr Owen JeffriesORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Introduction: The effect of eccentric exercise-induced muscle damage (EIMD) on cycling efficiency is unknown. The aim of the present study was to assess the effect of EIMD on gross and delta efficiency and the cardiopulmonary responses to cycle ergometry. Methods: Twenty- one recreational athletes performed cycling at 70%, 90% and 110% of the gas exchange threshold (GET) under control conditions (Control) and 24 h following an eccentric damaging protocol (Damage). Knee extensor isometric maximal voluntary contraction (MVC), potentiated twitch (Qtw,pot) and voluntary activation (VA) were assessed before Control and Damage. Gross and delta efficiency were assessed using indirect calorimetry, and cardiopulmonary responses were measured at each power output. Electromyography root-mean-square (EMGRMS) during cycling was also determined. Results: MVC was 25±18% lower for Damage than Control (p<0.001). Gross efficiency was lower for Damage than Control (p<0.001) by 0.55±0.79%, 0.59±0.73% and 0.60±0.87% for 70%, 90% and 110% GET, respectively. Delta efficiency was unchanged between conditions (p=0.513). Concurrently, cycling EMGRMS was higher for Damage than Control (p=0.004). An intensity-dependent increase in breath frequency and V̇ E/V̇ CO2 was found, which were higher for Damage only at 110% GET (p≤0.019). Conclusions: Thus, gross efficiency is reduced following EIMD. The concurrently higher EMGRMS suggests that increases in muscle activation in the presence of EIMD might have contributed to reduced gross efficiency. The lack of change in delta efficiency might relate to its poor reliability hindering the ability to detect change. The findings also show that EIMD- associated hyperventilation is dependent on exercise intensity, which might relate to increases in central command with EIMD.

Publication metadata

Author(s): Horner D, Jeffries O, Browntein CG

Publication type: Article

Publication status: Published

Journal: Medicine & Science in Sports & Exercise

Year: 2024

Pages: epub ahead of print

Online publication date: 15/05/2024

Acceptance date: 15/04/2024

Date deposited: 20/05/2024

ISSN (print): 0195-9131

ISSN (electronic): 1530-0315

Publisher: Lippincott Williams & Wilkins


DOI: 10.1249/MSS.0000000000003467

ePrints DOI: 10.57711/kavy-jt62


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