Document Detail


Quadriceps muscle energetics during incremental exercise in children and adults.
MedLine Citation:
PMID:  20019637     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: This study tested the hypothesis that the muscle metabolic responses of 9- to 12-yr-old children and young adults during incremental quadriceps exercise are dependent on age and sex. METHODS: Fifteen boys, 18 girls, 8 men, and 8 women completed a quadriceps step-incremental test to exhaustion inside a magnetic resonance scanner for determination of the muscle metabolic responses using P-magnetic resonance spectroscopy. Quadriceps muscle mass was determined using magnetic resonance imaging scans enabling comparison of metabolic data at a normalized power output. RESULTS: The power output and the energetic state at the Pi/PCr and pH intracellular thresholds (IT) were independent of age and sex. The rate of change in Pi/PCr against power output after the ITPi/PCr (S2) was lower in boys (0.158 +/- 0.089) and girls (0.257 +/- 0.110) compared with men (0.401 +/- 0.114, P < 0.001) and women (0.391 +/- 0.133, P = 0.014), respectively, with sex differences present for children only (P = 0.003). Above the ITpH, S2 was more rapid in the men (-0.041 +/- 0.022, P = 0.003) and girls (-0.030 +/- 0.013, P = 0.011) compared with boys (-0.019 +/- 0.007), with no differences between the girls and the women (-0.035 +/- 0.015, P = 0.479). The increase in Pi/PCr at exhaustion was lower in boys (0.85 +/- 0.38) than that in men (1.86 +/- 0.65, P < 0.001) and in girls (1.78 +/- 1.25) than that in women (4.97 +/- 3.52, P = 0.003), with sex differences in both the child (P = 0.005) and the adult groups (P = 0.019). CONCLUSIONS: During moderate-intensity exercise, muscle metabolism appears adult-like in 9- to 12-yr-old children, although both age- and sex-related differences in the "anaerobic" energy turnover are present during high-intensity exercise.
Authors:
Alan R Barker; Joanne R Welsman; Jonathan Fulford; Deborah Welford; Neil Armstrong
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  42     ISSN:  1530-0315     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-06-21     Completed Date:  2010-10-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1303-13     Citation Subset:  IM; S    
Affiliation:
Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Adult
Age Factors
Anaerobic Threshold / physiology
Child
Exercise / physiology*
Exercise Test
Female
Humans
Hydrogen-Ion Concentration
Male
Phosphates / metabolism
Physical Endurance / physiology*
Quadriceps Muscle / metabolism*
Sex Factors
Young Adult
Chemical
Reg. No./Substance:
0/Phosphates

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


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