Document Detail


Age- and sex-related differences in muscle phosphocreatine and oxygenation kinetics during high-intensity exercise in adolescents and adults.
MedLine Citation:
PMID:  20661873     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this investigation was to examine the adaptation of the muscle phosphates (e.g. phosphocreatine (PCr) and ADP) implicated in regulating oxidative phosphorylation, and oxygenation at the onset of high intensity exercise in children and adults. The hypotheses were threefold: primary PCr kinetics would be faster in children than adults; the amplitude of the PCr slow component would be attenuated in children; and the amplitude of the deoxyhaemoglobin/myoglobin (HHb) slow component would be reduced in children. Eleven children (5 girls, 6 boys, 13 +/- 1 years) and 11 adults (5 women, 6 men, 24 +/- 4 years) completed two to four constant work rate exercise tests within a 1.5 T MR scanner. Quadriceps muscle energetics during high intensity exercise were monitored using (31)P-MRS. Muscle oxygenation was monitored using near-infrared spectroscopy. The time constant for the PCr response was not significantly different in boys (31 +/- 10 s), girls (31 +/- 10 s), men (44 +/- 20 s) or women (29 +/- 14 s, main effects: age, p = 0.37, sex, p = 0.25). The amplitude of the PCr slow component relative to end-exercise PCr was not significantly different between children (23 +/- 23%) and adults (17 +/- 13%, p = 0.47). End-exercise [PCr] was significantly lower, and [ADP] higher, in females (18 +/- 4 mM and 53 +/- 16 microM) than males (23 +/- 4 mM, p = 0.02 and 37 +/- 11 microM, p = 0.02), but did not differ with age ([PCr]: p = 0.96, [ADP]: p = 0.72). The mean response time for muscle tissue deoxygenation was significantly faster in children (22 +/- 4 s) than adults (27 +/- 7 s, p = 0.01). The results of this study show that the control of oxidative metabolism at the onset of high intensity exercise is adult-like in 13-year-old children, but that matching of oxygen delivery to extraction is more precise in adults.
Authors:
Rebecca J Willcocks; Craig A Williams; Alan R Barker; Jon Fulford; Neil Armstrong
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  NMR in biomedicine     Volume:  23     ISSN:  1099-1492     ISO Abbreviation:  NMR Biomed     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-07-27     Completed Date:  2010-11-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8915233     Medline TA:  NMR Biomed     Country:  England    
Other Details:
Languages:  eng     Pagination:  569-77     Citation Subset:  IM    
Affiliation:
Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, UK.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Child
Exercise / physiology*
Female
Hemoglobins / metabolism
Humans
Male
Muscle, Skeletal / metabolism*
Myoglobin / metabolism
Oxidative Phosphorylation
Oxygen Consumption / physiology*
Phosphocreatine / metabolism*
Sex Characteristics
Young Adult
Chemical
Reg. No./Substance:
0/Hemoglobins; 0/Myoglobin; 67-07-2/Phosphocreatine; 9008-02-0/deoxyhemoglobin

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


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