Muscle performance and physical function are associated with voluntary rate of neuromuscular activation in older adults

David J. Clark, Carolynn Patten, Kieran F. Reid, Robert J. Carabello, Edward M. Phillips, Roger A. Fielding

Research output: Contribution to journalArticle

56 Scopus citations

Abstract

Background: Muscle power is related to mobility function in older adults, and effective power production requires rapid neuromuscular activation. Accordingly, this study examines the association of neuromuscular activation rate with muscle performance in persons of different age and mobility function. Methods: Participants were recruited to three experimental groups: middle-aged healthy adults (MH), older healthy adults (OH), and older adults with mobility limitations (OML). OH and OML were primarily differentiated by performance on the Short Physical Performance Battery (SPPB). Muscle performance (acceleration and power) and electromyography (EMG) were recorded during a maximal-effort leg press task at an absolute resistance (260 N) and at a relative resistance (70% of the one-repetition maximum [1RM]). Neuromuscular activation rate was quantifed as pre-movement time (duration between EMG onset and movement onset) and the rate of EMG rise. Results: Pre-movement time, rate of EMG rise, leg press acceleration, and leg press power were lower in OML relative to MH and OH but did not differ between OH and MH, with the exception of power at 70% 1RM. Across all older participants, rate of EMG rise was positively associated with acceleration, power, and the SPPB score. Conclusions: Slowing of neuromuscular activation rate is associated with compromised dynamic muscle performance, which may contribute to mobility limitations in some older adults. Future research should identify the precise neurophysiological impairments that contribute to declines in neuromuscular activation rate and mobility function with aging.

Original languageEnglish (US)
Pages (from-to)115-121
Number of pages7
JournalJournals of Gerontology - Series A Biological Sciences and Medical Sciences
Volume66 A
Issue number1
DOIs
StatePublished - Jan 1 2011
Externally publishedYes

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Keywords

  • Aging
  • Electromyography
  • Mobility
  • Strength

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology

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