| African runners exhibit greater fatigue resistance, lower lactate accumulation, and higher oxidative enzyme activity. | |
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MedLine Citation:
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PMID: 10066705 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Nine African and eight Caucasian 10-km runners resident at sea level volunteered. Maximal O2 consumption and peak treadmill velocity (PTV) were measured by using a progressive test, and fatigue resistance [time to fatigue (TTF)] was measured by using a newly developed high-intensity running test: 5 min at 72, 80, and 88% of individual PTV followed by 92% PTV to exhaustion. Skeletal muscle enzyme activities were determined in 12 runners and 12 sedentary control subjects. In a comparison of African and Caucasian runners, mean 10-km race time, maximal O2 consumption, and PTV were similar. In African runners, TTF was 21% longer (P < 0.01), plasma lactate accumulation after 5 min at 88% PTV was 38% lower (P < 0.05), and citrate synthase activity was 50% higher (27.9 +/- 7.5 vs. 18.6 +/- 2.1 micromol. g wet wt-1. min-1, P = 0.02). Africans accumulated lactate at a slower rate with increasing exercise intensity (P < 0.05). Among the entire group of runners, a higher citrate synthase activity was associated with a longer TTF (r = 0.70, P < 0.05), a lower plasma lactate accumulation (r = -0.73, P = 0.01), and a lower respiratory exchange ratio (r = -0.63, P < 0.05). We conclude that the African and Caucasian runners in the present study differed with respect to oxidative enzyme activity, rate of lactate accumulation, and their ability to sustain high-intensity endurance exercise. |
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Authors:
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A R Weston; O Karamizrak; A Smith; T D Noakes; K H Myburgh |
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Publication Detail:
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Type: Clinical Trial; Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 86 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 1999 Mar |
Date Detail:
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Created Date: 1999-05-07 Completed Date: 1999-05-07 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 915-23 Citation Subset: IM |
Affiliation:
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Medical Research Council/University of Cape Town Bioenergetics of Exercise Research Unit, Department of Physiology, Cape Town 7925, South Africa. A.Weston@cchs.usyd.edu.au |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult African Continental Ancestry Group Anaerobic Threshold / physiology Body Composition / physiology Body Height / physiology Body Weight / physiology Citrate (si)-Synthase / genetics*, metabolism European Continental Ancestry Group Humans Kinetics Lactic Acid / metabolism* Male Muscle Fatigue / genetics*, physiology Muscle Fibers, Skeletal / physiology Muscle, Skeletal / anatomy & histology, enzymology, metabolism Oxygen Consumption / genetics, physiology Running / physiology* |
| Chemical | |
Reg. No./Substance:
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50-21-5/Lactic Acid; EC 2.3.3.1/Citrate (si)-Synthase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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