@article{ref1,
title="Attenuated activation of knee extensor muscles during fast contractions in older men and women",
journal="European journal of applied physiology",
year="2020",
author="Kwon, MinHyuk and Senefeld, Jonathon W. and Hunter, Sandra K.",
volume="ePub",
number="ePub",
pages="ePub-ePub",
abstract="AIM: Reduced physical function and increased risk of falls in older adults are accompanied by age-related reductions in torque development of leg muscles, although the mechanisms and potential sex differences are not understood.   PURPOSE: To determine the mechanistic origins (neural vs. muscular) for the age-related reduction in torque development, we compared the peak rates of torque development (RTD) during electrically-evoked and fast voluntary contractions of the knee extensors between young and older men and women.   METHODS: Sets of single- and double-pulse electrical stimulations evoked contractions of the knee extensor muscles in 20 young (23.0 ± 0.8 years; 10 women) and 20 older adults (78.2 ± 1.5 years; 10 women), followed by voluntary isometric knee extension contractions with torque development as fast as possible that matched the torque during electrically-evoked contraction (10-40% maximal torque).   RESULTS: Peak RTD during fast-voluntary contractions was 41% less than electrically-evoked contractions (p < 0.001), but more so for older adults (44%) than young (38%, p = 0.04), with no sex differences. Peak RTD during fast-voluntary contractions was more variable between contractions for the older than young adults (77%MVC s-1 vs. 47%MVC s-1, p < 0.001). Additionally, older women exhibited greater variability than older men (81%MVC s-1 vs. 72%MVC s-1, p = 0.04) with no sex-related differences within the young adults.   CONCLUSION: Older adults had slower and more variable RTD during voluntary contractions than young adults, particularly older women. The limited age-related differences in electrically-evoked RTD suggest the primary mechanism for the slower torque development of the knee extensor muscles in older men and women involve reduced neural activation.<p /> <p>Language: en</p>",
language="en",
issn="1439-6319",
doi="10.1007/s00421-020-04451-0",
url="http://dx.doi.org/10.1007/s00421-020-04451-0"
}