Document Detail

Effect of exercise-diet manipulation on muscle glycogen and its subsequent utilization during performance.
MedLine Citation:
PMID:  7333741     Owner:  NLM     Status:  MEDLINE    
This study examined the effect of three exercise-diet regimens on muscle glycogen supercompensation and subsequent performance during a 20.9-km run. A diet containing 15% carbohydrate (CHO,L), 50% CHO (M), or 70% (CHO (H) was arranged in three trials as follows: trial A = 3 days L, 3 days H; trial B = 3 days M, 3 days H; trial C = 6 days M. For each trial a 5-day depletion-taper exercise sequence was conducted on the treadmill at 73% VO2 max. The runs were 90, 40, 40, 20, and 20 min, respectively. A day of rest preceded the 20.9-km performance run. Muscle biopsies were obtained from the gastrocnemius on days 4 and 7 (both prior to and after the performance run). Trials A, B, and C elevated muscle glycogen to 207, 203, and 159 mmol glucosyl units/kg wet tissue (mmG), respectively. The performance run in both trials A and B utilized significantly more glycogen than in trial C: 5.0 and 5.1 mmG/km vs. 3.1 mmG/km. There were, however, no differences in either performance run times or post-performance run glycogen levels between the trials. These data demonstrate that (1) muscle glycogen can be elevated to high levels with a moderate exercise-diet regimen; (2) initial muscle glycogen levels influence the amount subsequently utilized during exercise; (3) carbohydrate loading is of no benefit to performance for trained runners during a 20.9-km run.
W M Sherman; D L Costill; W J Fink; J M Miller
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  International journal of sports medicine     Volume:  2     ISSN:  0172-4622     ISO Abbreviation:  Int J Sports Med     Publication Date:  1981 May 
Date Detail:
Created Date:  1982-05-21     Completed Date:  1982-05-21     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8008349     Medline TA:  Int J Sports Med     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  114-8     Citation Subset:  IM; S    
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MeSH Terms
Dietary Carbohydrates / administration & dosage
Glycogen / metabolism*
Muscles / metabolism*
Oxygen Consumption
Physical Exertion*
Reg. No./Substance:
0/Dietary Carbohydrates; 9005-79-2/Glycogen

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

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