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

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 95/6/2361    most recent 00724.2002v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (25) Citing Articles via Google Scholar Google Scholar Articles by Lanza, I. R. Articles by Kent-Braun, J. A. Search for Related Content PubMed PubMed Citation Articles by Lanza, I. R. Articles by Kent-Braun, J. A.

Effects of age on human muscle torque, velocity, and power in two muscle groups

Department of Exercise Science, University of Massachusetts, Amherst, Massachusetts 01003

Submitted 6 August 2002 ; accepted in final form 7 August 2003

The purpose of this study was to test the hypotheses that, under isovelocity conditions, older compared with young humans would 1) be slower to reach target velocity and 2) exhibit a downward shift in the torque-velocity and power-velocity relationships in the ankle dorsiflexor and knee extensor muscles. We studied 12 young (26 ± 5 yr, 6 men/6 women) and 12 older (72 ± 6 yr, 6 men/6 women) healthy adults during maximal voluntary concentric contractions at preset target velocities (dorsiflexion: 0–240°/s; knee extension: 0–400°/s) using an isokinetic dynamometer. The time to target velocity was longer in older subjects in the dorsiflexors and knee extensors (both P 0.02). Averaged across all velocities, older subjects produced 26% less concentric torque and power in the dorsiflexors (P < 0.01) and 32% less in the knee extensors (P < 0.01). The downward shift in the torque-velocity relationship persisted even when torque was expressed relative to each subject's maximum. In the knee extensors only, the age-related decrement in power increased with increasing velocities, suggesting that this muscle group may be more susceptible to age-related losses of function than the dorsiflexor muscles are. In support of our hypotheses, these results demonstrate an age-related impairment in the dynamic performance of two functionally distinct muscle groups in healthy older adults. With age, the impairment of dynamic performance appears to exceed the loss of isometric performance, particularly in the knee extensor muscles.

ankle dorsiflexors; knee extensors; sarcopenia; dynamic; isometric

This article has been cited by other articles:

				I. R. Lanza, R. G. Larsen, and J. A. Kent-Braun Effects of old age on human skeletal muscle energetics during fatiguing contractions with and without blood flow J. Physiol., September 15, 2007; 583(3): 1093 - 1105. [Abstract] [Full Text] [PDF]

				C. J. McNeil and C. L. Rice Fatigability Is Increased With Age During Velocity-Dependent Contractions of the Dorsiflexors J. Gerontol. A Biol. Sci. Med. Sci., June 1, 2007; 62(6): 624 - 629. [Abstract] [Full Text] [PDF]

				I. R. Lanza, D. E. Befroy, and J. A. Kent-Braun Age-related changes in ATP-producing pathways in human skeletal muscle in vivo J Appl Physiol, November 1, 2005; 99(5): 1736 - 1744. [Abstract] [Full Text] [PDF]

				A. J. Cheng and C. L. Rice Fatigue and recovery of power and isometric torque following isotonic knee extensions J Appl Physiol, October 1, 2005; 99(4): 1446 - 1452. [Abstract] [Full Text] [PDF]

				J. M. Thom, C. I. Morse, K. M. Birch, and M. V. Narici Triceps Surae Muscle Power, Volume, and Quality in Older Versus Younger Healthy Men J. Gerontol. A Biol. Sci. Med. Sci., September 1, 2005; 60(9): 1111 - 1117. [Abstract] [Full Text] [PDF]

				E. Simoneau, A. Martin, and J. Van Hoecke Muscular Performances at the Ankle Joint in Young and Elderly Men J. Gerontol. A Biol. Sci. Med. Sci., April 1, 2005; 60(4): 439 - 447. [Abstract] [Full Text] [PDF]

				D. G. Candow and P. D. Chilibeck Differences in Size, Strength, and Power of Upper and Lower Body Muscle Groups in Young and Older Men J. Gerontol. A Biol. Sci. Med. Sci., February 1, 2005; 60(2): 148 - 156. [Abstract] [Full Text] [PDF]

				H. H. C. M. Savelberg and K. Meijer The Effect of Age and Joint Angle on the Proportionality of Extensor and Flexor Strength at the Knee Joint J. Gerontol. A Biol. Sci. Med. Sci., November 1, 2004; 59(11): 1120 - 1128. [Abstract] [Full Text] [PDF]

				I. R. Lanza, D. W. Russ, and J. A. Kent-Braun Age-related enhancement of fatigue resistance is evident in men during both isometric and dynamic tasks J Appl Physiol, September 1, 2004; 97(3): 967 - 975. [Abstract] [Full Text] [PDF]