Document Detail

Nuclear magnetic resonance evidence of different muscular adaptations after resistance training.
MedLine Citation:
PMID:  9821899     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To evaluate muscle bioenergetics, muscle cross-sectional area (CSA), and soreness when the gastrocnemius was subjected to concentric and concentric/eccentric resistance training modes. DESIGN: Prospective study, before and after training. The subjects served as their own controls. SETTING: Rehabilitation center and nuclear magnetic resonance spectroscopy unit of a university hospital. PARTICIPANTS: Sixteen healthy young volunteers from the local physiotherapist school. INTERVENTION: Two distinct resistive training programs were evaluated on the gastrocnemius: a protocol consisting of concentric contractions only and a mixed concentric/eccentric program. MAIN OUTCOME MEASURES: Maximal isometric resistance was measured after each training session. Before and after training, muscle CSA was appreciated using magnetic resonance imaging, whereas changes in muscle pH, phosphorus metabolite ratios, maximal oxidative power (Pmax), and oxidative phosphorylation were studied using 31P nuclear magnetic resonance spectroscopy at rest and during an incremental exercise protocol. RESULTS: Magnetic resonance imaging revealed a significant increase (7.1%) in the gastrocnemius CSA in the concentric-eccentric group only. The PCr/Pi (8.3 +/- 0.9 vs 10.4 +/- 1.7) and PCr/ATP (3.68 +/- .36 vs 4.07 +/- .27) resting ratios increased significantly (p = .008) after concentric-eccentric resistance training. Pmax was significantly improved in the concentric-eccentric group (7.0 +/- 2.1W vs 8.4 +/- 1.8W: p < .02). This mixed protocol also reduced the incidence of muscular soreness. CONCLUSION: The data suggest that the improved oxidative mechanical power output could be due mainly to a greater muscle cross-section in the concentric-eccentric group, with circumstantial evidence suggesting a relatively higher type IIa fiber activity.
P M Walker; F Brunotte; I Rouhier-Marcer; Y Cottin; J M Casillas; P Gras; J P Didier
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Archives of physical medicine and rehabilitation     Volume:  79     ISSN:  0003-9993     ISO Abbreviation:  Arch Phys Med Rehabil     Publication Date:  1998 Nov 
Date Detail:
Created Date:  1998-12-04     Completed Date:  1998-12-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985158R     Medline TA:  Arch Phys Med Rehabil     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1391-8     Citation Subset:  AIM; IM; S    
Service de Spectroscopie RMN et Médecine Nucléaire, Centre Hospitalier Universitaire de Dijon, France.
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MeSH Terms
Energy Metabolism*
Exercise / physiology*
Exercise Therapy*
Magnetic Resonance Spectroscopy
Muscle, Skeletal / metabolism*,  pathology
Prospective Studies
Comment In:
Arch Phys Med Rehabil. 1999 May;80(5):607   [PMID:  10326929 ]

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