AUTHOR=Chrismas Bryna C. R. , Taylor Lee , Siegler Jason C. , Midgley Adrian W. 

TITLE=A Reduction in Maximal Incremental Exercise Test Duration 48 h Post Downhill Run Is Associated with Muscle Damage Derived Exercise Induced Pain

JOURNAL=Frontiers in Physiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00135

DOI=10.3389/fphys.2017.00135

ISSN=1664-042X

ABSTRACT=<p><bold>Purpose:</bold> To examine whether exercise induced muscle damage (EIMD) and muscle soreness reduce treadmill maximal incremental exercise (MIE) test duration, and true maximal physiological performance as a consequence of exercise induced pain (EIP) and perceived effort.</p><p><bold>Methods:</bold> Fifty (14 female), apparently healthy participants randomly allocated into a control group (CON, <italic>n</italic> = 10), or experimental group (EXP, <italic>n</italic> = 40) visited the laboratory a total of six times: visit 1 (familiarization), visit 2 (pre 1), visit 3 (pre 2), visit 4 (intervention), visit 5 (24 h post) and visit 6 (48 h post). Both groups performed identical testing during all visits, except during visit 4, where only EXP performed a 30 min downhill run and CON performed no exercise. During visits 2, 3, and 6 all participants performed MIE, and the following measurements were obtained: time to exhaustion (TTE), EIP, maximal oxygen consumption <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mtext>V</mml:mtext></mml:mrow><mml:mo>·</mml:mo></mml:mover><mml:msub><mml:mrow><mml:mtext>O</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mtext>max</mml:mtext></mml:mrow></mml:msub></mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math></inline-formula>, rate of perceived exertion (RPE), maximum heart rate (HR<sub>max</sub>), maximum blood lactate (BLa<sub>max</sub>), and the contribution of pain to terminating the MIE (assessed using a questionnaire). Additionally during visits 1, 2, 3, 5, and 6 the following markers of EIMD were obtained: muscle soreness, maximum voluntary contraction (MVC), voluntary activation (VA), creatine kinase (CK).</p><p><bold>Results:</bold> There were no significant differences (<italic>p</italic> ≥ 0.32) between any trials for any of the measures obtained during MIE for CON. In EXP, TTE decreased by 34 s (3%), from pre 2 to 48 h post (<italic>p</italic> &lt; 0.001). There was a significant association between group (EXP, CON) and termination of the MIE due to “pain” during 48 h post (χ<sup>2</sup> = 14.7, <italic>p</italic> = 0.002).</p><p><bold>Conclusion:</bold> EIMD resulted in premature termination of a MIE test (decreased TTE), which was associated with EIP, MVC, and VA. The exact mechanisms responsible for this require further investigation.</p>