Document Detail

Functional and structural adaptations in skeletal muscle of trained athletes.
MedLine Citation:
PMID:  3366734     Owner:  NLM     Status:  MEDLINE    
Twitch contractile and ultrastructural characteristics of the human triceps surae were determined in six male strength-trained athletes, six endurance-trained athletes, six active controls, and seven sedentary controls of similar height and age. Twitch contraction time in the triceps surae complex was 20% longer in strength-trained and sedentary groups than in endurance-trained or active control groups. In the 15 subjects peak twitch torque and one-half relation time in the triceps surae were 22.6 +/- 7.9 N.m and 91.1 +/- 18.3 ms, respectively. Mean fiber area in the gastrocnemius was approximately 1.6-, 1.7-, and 2.5-fold greater in the active control, endurance-trained, and strength-trained groups, respectively, relative to the sedentary group. Despite these large differences in fiber areas, the fiber fractional volume of the sarcoplasmic reticulum-transverse tubule network averaged 3.38 +/- 0.86% and 5.50 +/- 0.94% in type I and type II fibers, respectively, in all subjects. The fractional fiber volume of cytoplasm and lipid were similar for all four groups. However, mitochondrial volume was approximately 30% lower in both fiber types of the strength-trained group relative to the other groups. This implies that with exercise-induced hypertrophy, the sarcoplasmic reticulum, cytoplasm, and lipid components increase proportionately with contractile protein, whereas the mitochondrial fraction does not. The proportion of type I fibers in the soleus, medial gastrocnemius, and lateral gastrocnemius was 75.2 +/- 8.3, 58.5 +/- 6.1, and 52.4 +/- 4.2%, respectively, and was similar in all subject groups. The results demonstrate that twitch duration is prolonged in strength-trained athletes relative to endurance athletes.(ABSTRACT TRUNCATED AT 250 WORDS)
S E Alway; J D MacDougall; D G Sale; J R Sutton; A J McComas
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  64     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1988 Mar 
Date Detail:
Created Date:  1988-06-23     Completed Date:  1988-06-23     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:  1114-20     Citation Subset:  IM; S    
Department of Physical Education, McMaster University, Hamilton, Ontario, Canada.
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MeSH Terms
Microscopy, Electron
Microtubules / ultrastructure
Mitochondria, Muscle / ultrastructure
Muscle Contraction*
Muscles / analysis,  physiology*,  ultrastructure
Physical Exertion*
Sarcoplasmic Reticulum / ultrastructure*
Weight Lifting

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

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