Locomotor muscle fatigue is not critically regulated after prior upper body exercise

Johnson, M.A. ORCID: 0000-0002-8226-9438, Sharpe, G.R., Williams, N.C. ORCID: 0000-0002-2607-4572 and Hannah, R., 2015. Locomotor muscle fatigue is not critically regulated after prior upper body exercise. Journal of Applied Physiology, 119 (7), pp. 840-850. ISSN 8750-7587

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Abstract

This study examined the effects of prior upper body exercise on subsequent high-intensity cycling exercise tolerance and associated changes in neuromuscular function and perceptual responses. Eight men performed three fixed work-rate (85% peak power) cycling tests: 1) to the limit of tolerance (CYC); 2) to the limit of tolerance after prior high-intensity arm-cranking exercise (ARM-CYC); and 3) without prior exercise and for an equal duration as ARM-CYC (ISOTIME). Peripheral fatigue was assessed via changes in potentiated quadriceps twitch force during supramaximal electrical femoral nerve stimulation. Voluntary activation was assessed using twitch interpolation during maximal voluntary contractions. Cycling time during ARM-CYC and ISOTIME (4.33 ± 1.10 min) was 38% shorter than during CYC (7.46 ± 2.79 min) (P < 0.001). Twitch force decreased more after CYC (−38 ± 13%) than ARM-CYC (−26 ± 10%) (P = 0.004) and ISOTIME (−24 ± 10%) (P = 0.003). Voluntary activation was 94 ± 5% at rest and decreased after CYC (89 ± 9%, P = 0.012) and ARM-CYC (91 ± 8%, P = 0.047). Rating of perceived exertion for limb discomfort increased more quickly during cycling in ARM-CYC [1.83 ± 0.46 arbitrary units (AU)/min] than CYC (1.10 ± 0.38 AU/min, P = 0.003) and ISOTIME (1.05 ± 0.43 AU/min, P = 0.002), and this was correlated with the reduced cycling time in ARM-CYC (r = −0.72, P = 0.045). In conclusion, cycling exercise tolerance after prior upper body exercise is potentially mediated by central fatigue and intolerable levels of sensory perception rather than a critical peripheral fatigue limit.

Item Type: Journal article
Alternative Title: Prior upper body exercise and locomotor muscle fatigue [running head]
Publication Title: Journal of Applied Physiology
Creators: Johnson, M.A., Sharpe, G.R., Williams, N.C. and Hannah, R.
Publisher: American Physiological Society
Place of Publication: Bethesda, MD
Date: 1 October 2015
Volume: 119
Number: 7
ISSN: 8750-7587
Identifiers:
NumberType
10.1152/japplphysiol.00072.2015DOI
Divisions: Schools > School of Science and Technology
Depositing User: EPrints Services
Date Added: 09 Oct 2015 11:06
Last Modified: 09 Jun 2017 13:49
URI: http://irep.ntu.ac.uk/id/eprint/22736

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