Document Detail

Age-related resistance to skeletal muscle fatigue is preserved during ischemia.
MedLine Citation:
PMID:  17690199     Owner:  NLM     Status:  MEDLINE    
During voluntary contractions, the skeletal muscle of healthy older adults often fatigues less than that of young adults, a result that has been explained by relatively greater reliance on muscle oxidative metabolism in the elderly. Our aim was to investigate whether this age-related fatigue resistance was eliminated when oxidative metabolism was minimized via ischemia induced by cuff (220 mmHg). We hypothesized that 1) older men (n = 12) would fatigue less than young men (n = 12) during free-flow (FF) contractions; 2) both groups would fatigue similarly during ischemia; and 3) reperfusion would reestablish the fatigue resistance of the old. Subjects performed 6 min of intermittent, maximal voluntary isometric contractions of the ankle dorsiflexors under FF and ischemia-reperfusion (IR) conditions. Ischemia was maintained for the first 3 min of contractions, followed by rapid cuff deflation and reperfusion for 3 additional minutes of contractions. Central activation, peripheral activation, and muscle contractile properties were measured at 3 and 6 min of contractions. Older men fatigued less than young men during FF (P </= 0.02), ischemia (P < 0.001), and reperfusion (P < 0.001). During FF, activation and contractile properties changed similarly across age groups. At the end of ischemia, central (P = 0.02) and peripheral (P </= 0.03) activation declined more in the young, with no effect of age on the changes in contractile properties. Thus age-related fatigue resistance was evident during FF and IR, indicating that differences in blood flow and oxidative metabolism do not explain the fatigue resistance of old age.
Linda H Chung; Damien M Callahan; Jane A Kent-Braun
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Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2007-08-09
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  103     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-10-29     Completed Date:  2008-01-08     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:  1628-35     Citation Subset:  IM    
Dept. of Kinesiology, Univ. of Massachusetts, 108 Totman Bldg., 30 Eastman Lane, Amherst, MA 01003, USA.
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MeSH Terms
Age Factors
Aging* / metabolism
Electric Stimulation
Ischemia / metabolism,  physiopathology*
Isometric Contraction
Muscle Contraction*
Muscle Fatigue*
Muscle Strength
Muscle, Skeletal / blood supply*,  metabolism,  physiopathology*
Oxidative Stress
Regional Blood Flow
Time Factors

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

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