Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/34760
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Type: Journal article
Title: Motor-unit coherence during isometric contractions is greater in a hand muscle of older adults
Author: Semmler, J.
Kornatz, K.
Enoka, R.
Citation: Journal of Neurophysiology, 2003; 90(2):1346-1349
Publisher: Amer Physiological Soc
Issue Date: 2003
ISSN: 0022-3077
1522-1598
Statement of
Responsibility: 
John G. Semmler, Kurt W. Kornatz and Roger M. Enoka
Abstract: The purpose of this study was to quantify the strength of motor-unit coherence from the first dorsal interosseus muscle in young and old adults using data obtained in a previous study, where no differences in motor-unit synchronization between the two groups were observed. The strength of motor-unit coherence was quantified from 47 motor-unit pairs in 11 young adults (age 24.1 ± 4.1 yrs) and from 48 motor-unit pairs in 14 old adults (age 70.4 ± 5.9 yrs). The strength of motor-unit coherence was greater in old adults, particularly at low frequencies of 5–9 Hz (85% greater in old adults at 5 Hz). In addition, the older adults expressed an extra oscillation at approximately 12–13 Hz that was not present in the young subjects. These data demonstrate that common oscillatory inputs to motor neurons (motor-unit coherence) are enhanced in older adults despite no age-related difference in the strength of shared inputs (synchronization). Furthermore, the data emphasize that measures of motor-unit synchronization and coherence highlight different features of the same common input, and a coherence analysis may be a more sensitive tool to characterize shared input to motor neurons.
Keywords: Hand; Muscle, Skeletal; Humans; Electrophysiology; Aging; Isometric Contraction; Adult; Aged
Description: Copyright © 2003 The American Physiological Society
RMID: 0020063353
DOI: 10.1152/jn.00941.2002
Published version: http://jn.physiology.org/cgi/content/abstract/90/2/1346
Appears in Collections:Molecular and Biomedical Science publications

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