Document Detail


Effect of unweighting on skeletal muscle use during exercise.
MedLine Citation:
PMID:  7559216     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exercise-induced spin-spin relaxation time (T2) shifts in magnetic resonance (MR) images were used to test the hypothesis that more muscle would be used to perform a given submaximal task after 5 wk of unweighting. Before and after unilateral lower limb suspension (ULLS), 7 subjects performed 5 sets of 10 unilateral concentric actions with the quadriceps femoris muscle group (QF) at each of 4 loads: 25, 40, 55, and 70% of maximum. T2-weighted MR images of the thigh were collected at rest and after each relative load. ULLS elicited a 20% decrease in strength of the left unweighted QF and a 14% decrease in average cross-sectional area (CSA) with no changes in the right weight-bearing QF. Average CSA of the left or right QF showing exercise-induced T2 shift increased as a function of exercise intensity both before and after ULLS. On average, 12 +/- 1, 15 +/- 2, 18 +/- 2, and 22 +/- 1 cm2 of either QF showed elevated T2 for the 25, 40, 55, and 70% loads, respectively, before ULLS. Average CSA of the left but not the right QF, showing elevated T2 after ULLS, was increased to 16 +/- 2, 23 +/- 3, 31 +/- 7, and 39 +/- 5 cm2, respectively. The results indicated that unweighting increased exercise-induced T2 shift in MR images, presumably due to greater muscle mass involvement in exercise after than before unweighting, suggesting a change in motor control.
Authors:
L L Ploutz-Snyder; P A Tesch; D J Crittenden; G A Dudley
Related Documents :
16138786 - Multiple sprint work : physiological responses, mechanisms of fatigue and the influence...
7559216 - Effect of unweighting on skeletal muscle use during exercise.
17941596 - A field trial evaluation of the prophylactic efficacy of amitraz-impregnated collars ag...
2220306 - Improved energy kinetics following high protein diet in mcardle's syndrome. a 31p magne...
1930766 - The effect of exercise on depressive symptoms in the moderately depressed elderly.
16808126 - Severe acute respiratory syndrome in a naval diver.
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  79     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1995 Jul 
Date Detail:
Created Date:  1995-11-14     Completed Date:  1995-11-14     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:  168-75     Citation Subset:  IM; S    
Affiliation:
Department of Biological Sciences, Ohio University, Athens 45701, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Casts, Surgical
Female
Humans
Immobilization
Leg
Magnetic Resonance Imaging
Male
Muscle, Skeletal / anatomy & histology,  physiology*
Physical Exertion*
Weight-Bearing*
Investigator
Investigator/Affiliation:
P A Tesch / Karolinska Inst, Stockholm, Sweden; G A Dudley / NASA KSC

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


Previous Document:  Fiber type-specific effects of clenbuterol and exercise training on insulin-resistant muscle.
Next Document:  Effects of nasal positive-pressure hyperventilation on the glottis in normal awake subjects.