Document Detail

Age-related differences in isometric and dynamic strength and endurance.
MedLine Citation:
PMID:  7089062     Owner:  NLM     Status:  MEDLINE    
To measure age-related skeletal muscle changes, 30 healthy, moderately active women performed isometric and dynamic strength and endurance tests of their left quadriceps femoris muscle groups. Fifteen of the subjects were ages 20 to 29 years and 15 were ages 50 to 80 years. A cybex II isokinetic dynamometer was used to measure the torque output isometrically with the knee at 90 degrees of flexion on three trials. In addition, each subject performed three trials from 90 degrees of knee flexion to full knee extension and back to 90 degrees of knee flexion with the velocity of the isokinetic dynamometer set at 10 rpms. Endurance time was calculated to be the length of time a torque output of at least 50 percent of the maximal strength could be maintained. The t tests done revealed a significant difference between the two groups on isometric and dynamic strength, while no significant difference was found on isometric or dynamic endurance. Statistically correcting for the extraneous variables, height and weight, through a partial correlation revealed a significant negative correlation between age and strength. The younger subjects had higher torque outputs, both isometrically and dynamically, than the older subjects. The same partial correlation between isometric endurance and age and dynamic endurance and age demonstrated no significant correlation. The fact that endurance did not change in this older population while strength did may be the result of fast-twitch and slow-twitch muscle fibers changing with age.
T Johnson
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Physical therapy     Volume:  62     ISSN:  0031-9023     ISO Abbreviation:  Phys Ther     Publication Date:  1982 Jul 
Date Detail:
Created Date:  1982-08-14     Completed Date:  1982-08-14     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0022623     Medline TA:  Phys Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  985-9     Citation Subset:  AIM; IM; S    
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MeSH Terms
Isometric Contraction
Leg / physiology
Middle Aged
Muscle Contraction
Muscles / physiology*
Physical Endurance
Physical Exertion

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

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