Document Detail


Muscle power and metabolism in maximal intermittent exercise.
MedLine Citation:
PMID:  3700299     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Muscle power and the associated metabolic changes in muscle were investigated in eight male human subjects who performed four 30-s bouts of maximal isokinetic cycling at 100 rpm, with 4-min recovery intervals. In the first bout peak power and total work were (mean +/- SE) 1,626 +/- 102 W and 20.83 +/- 1.18 kJ, respectively; muscle glycogen decreased by 18.2 mmol/kg wet wt, lactate increased to 28.9 +/- 2.7 mmol/kg, and there were up to 10-fold increases in glycolytic intermediates. External power and work decreased by 20% in both the second and third exercise periods, but no further change occurred in the fourth bout. Muscle glycogen decreased by an additional 14.8 mmol/kg after the second exercise and thereafter remained constant. Muscle adenosine triphosphate (ATP) was reduced by 40% from resting after each exercise period; creatine phosphate (CP) decreased successively to less than 5% of resting; in the recovery periods ATP and CP increased to 76 and 95% of initial resting levels, respectively. Venous plasma glycerol increased linearly to 485% of resting; free fatty acids did not change. Changes in muscle glycogen, lactate, and glycolytic intermediates suggested rate limitation at phosphofructokinase during the first and second exercise periods, and phosphorylase in the third and fourth exercise periods. Despite minimal glycolytic flux in the third and fourth exercise periods, subjects generated 1,000 W peak power and sustained 400 W for 30 s, 60% of the values recorded in the first exercise period.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
N McCartney; L L Spriet; G J Heigenhauser; J M Kowalchuk; J R Sutton; N L Jones
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  60     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1986 Apr 
Date Detail:
Created Date:  1986-06-09     Completed Date:  1986-06-09     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1164-9     Citation Subset:  IM; S    
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MeSH Terms
Descriptor/Qualifier:
Acid-Base Equilibrium
Adenosine Triphosphate / metabolism
Adult
Energy Metabolism
Glycerol / blood
Glycogen / metabolism
Glycolysis
Humans
Male
Muscle Contraction*
Muscles / metabolism*
Oxygen Consumption
Phosphocreatine / metabolism
Physical Exertion*
Triglycerides / metabolism
Chemical
Reg. No./Substance:
0/Triglycerides; 56-65-5/Adenosine Triphosphate; 56-81-5/Glycerol; 67-07-2/Phosphocreatine; 9005-79-2/Glycogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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