HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Cited by other online articles Google Scholar Articles by Christou, E. A. Articles by Carlton, L. G. Articles citing this Article PubMed PubMed Citation Articles by Christou, E. A. Articles by Carlton, L. G.

Old Adults Exhibit Greater Motor Output Variability Than Young Adults Only During Rapid Discrete Isometric Contractions

^a University of Illinois at Urbana-Champaign

Correspondence: Evangelos A. Christou, Neural Control of Movement Lab, Department of Kinesiology and Applied Physiology, University of Colorado at Boulder, Boulder, CO 80309-0354 E-mail: echristo{at}colorado.edu.

Decision Editor: John A. Faulkner, PhD

The purpose of this study was to examine the ability of young and elderly individuals to control submaximum levels of force (5–90%) during continuous and rapid discrete isometric contractions of the quadriceps femoris. Participants were 24 young (25.3 ± 2.8 years) and 24 elderly individuals (73.3 ± 5.5 years) that were healthy and active. The strength of elderly participants was approximately 40% lower than young participants. The standard deviation and coefficient of variation (CV) of force were greater during discrete contractions than during continuous isometric contractions. During continuous isometric contractions, young and elderly participants exhibited similar CVs of force. During discrete contractions, however, elderly participants exhibited greater CVs for peak force and impulse and greater standard deviations and CVs for temporal characteristics than young participants. Results suggest that the control of force in active elderly people declines only during rapid discrete contractions and that this decline may be associated with declines in temporal characteristics of the force production.

This article has been cited by other articles: (Search Google Scholar for Other Citing Articles)

				M. Shinohara, C. T. Moritz, M. A. Pascoe, and R. M. Enoka Prolonged muscle vibration increases stretch reflex amplitude, motor unit discharge rate, and force fluctuations in a hand muscle J Appl Physiol, November 1, 2005; 99(5): 1835 - 1842. [Abstract] [Full Text] [PDF]

				J. J. Sosnoff, D. E. Vaillancourt, and K. M. Newell Aging and Rhythmical Force Output: Loss of Adaptive Control of Multiple Neural Oscillators J Neurophysiol, January 1, 2004; 91(1): 172 - 181. [Abstract] [Full Text]

				M. Shinohara, Y. Yoshitake, M. Kouzaki, H. Fukuoka, and T. Fukunaga Strength training counteracts motor performance losses during bed rest J Appl Physiol, October 1, 2003; 95(4): 1485 - 1492. [Abstract] [Full Text] [PDF]

				E. A. Christou, Y. Yang, and K. S. Rosengren Rapid Communication. Taiji Training Improves Knee Extensor Strength and Force Control in Older Adults J. Gerontol. A Biol. Sci. Med. Sci., August 1, 2003; 58(8): M763 - 766. [Abstract] [Full Text] [PDF]

				D. E. Vaillancourt and K. M. Newell Aging and the time and frequency structure of force output variability J Appl Physiol, March 1, 2003; 94(3): 903 - 912. [Abstract] [Full Text] [PDF]

				E. A. Christou and L. G. Carlton Age and contraction type influence motor output variability in rapid discrete tasks J Appl Physiol, August 1, 2002; 93(2): 489 - 498. [Abstract] [Full Text] [PDF]