Relative differences in strength and power from slow to fast isokinetic velocities may reflect dynapenia

Nathaniel D M Jenkins; Terry J Housh; Ty B Palmer; Kristen C Cochrane; Haley C Bergstrom; Glen O Johnson; Richard J Schmidt; Joel T Cramer

doi:10.1002/mus.24505

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Relative differences in strength and power from slow to fast isokinetic velocities may reflect dynapenia

Journal article

Peer reviewed

Relative differences in strength and power from slow to fast isokinetic velocities may reflect dynapenia

Nathaniel D M Jenkins, Terry J Housh, Ty B Palmer, Kristen C Cochrane, Haley C Bergstrom, Glen O Johnson, Richard J Schmidt and Joel T Cramer

Muscle & nerve, Vol.52(1), pp.120-130

07/2015

DOI: 10.1002/mus.24505

PMID: 25363299

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Abstract

We compared absolute and normalized values for peak torque (PT), mean power (MP), rate of velocity development, and electromyography (EMG) amplitude during maximal isometric and concentric isokinetic leg extension muscle actions, as well as the %decrease in PT and %increase in MP from 1.05 to 3.14 rad·s(-1) in younger versus older men. Measurements were performed twice for reliability. Isokinetic measurements were normalized to the isometric muscle actions. Absolute isometric PT, isokinetic PT and MP, and EMG amplitudes at 1.05 and 3.14 rad·s(-1) were greater in the younger men, although normalizing to isometric PT eliminated the age differences. The older men exhibited greater %decrease in PT (37.2% vs. 31.3%) and lower %increase in MP (87.6% vs. 126.4%) regardless of normalization. Normalization eliminated absolute differences in isokinetic strength and power, but the relative differences from slow to fast velocities may reflect dynapenia characterized by age-related decreases in fast-twitch fiber function.

Adolescent

Age Factors

Aged

Aged, 80 and over

Analysis of Variance

Electromyography

Humans

Leg - innervation

Male

Muscle Contraction - physiology

Muscle Strength - physiology

Muscle Strength Dynamometer

Muscle, Skeletal - physiology

Sarcopenia - diagnosis

Sarcopenia - physiopathology

Torque

Young Adult

Details

Title: Subtitle: Relative differences in strength and power from slow to fast isokinetic velocities may reflect dynapenia
Creators: Nathaniel D M Jenkins - University of Nebraska–Lincoln
Terry J Housh - University of Nebraska–Lincoln
Ty B Palmer - Oklahoma State University
Kristen C Cochrane - University of Nebraska–Lincoln
Haley C Bergstrom - University of Kentucky
Glen O Johnson - University of Nebraska–Lincoln
Richard J Schmidt - University of Nebraska–Lincoln
Joel T Cramer - University of Nebraska–Lincoln
Resource Type: Journal article
Publication Details: Muscle & nerve, Vol.52(1), pp.120-130
DOI: 10.1002/mus.24505
PMID: 25363299
NLM abbreviation: Muscle Nerve
ISSN: 0148-639X
eISSN: 1097-4598
Grant note: name: University of Nebraska Agricultural Research Division with funds provided through the Hatch Act (Agency: United States Department of Agriculture; DOI: 10.13039/100005825, name: National Institute of Food and Agriculture, award: 1000080, NEB-36-078
Language: English
Date published: 07/2015
Academic Unit: Center for Social Science Innovation; Injury Prevention Research Center; Health, Sport, and Human Physiology
Record Identifier: 9984259398302771

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