Document Type

Article

Language

eng

Format of Original

10 p.

Publication Date

1-2017

Publisher

Elsevier

Source Publication

Experimental Gerontology

Source ISSN

0531-5565

Original Item ID

DOI: 10.1016/j.exger.2016.10.008; PMID: 27989926

Abstract

Introduction

It is not known whether the age-related increase in fatigability of fast dynamic contractions in lower limb muscles also occurs in upper limb muscles. We compared age-related fatigability and variability of maximal-effort repeated dynamic contractions in the knee extensor and elbow flexor muscles; and determined associations between fatigability, variability of velocity between contractions and functional performance.

Methods

35 young (16 males; 21.0 ± 2.6 years) and 32 old (18 males; 71.3 ± 6.2 years) adults performed a dynamic fatiguing task involving 90 maximal-effort, fast, concentric, isotonic contractions (1 contraction/3 s) with a load equivalent to 20% maximal voluntary isometric contraction (MVIC) torque with the elbow flexor and knee extensor muscles on separate days. Old adults also performed tests of balance and walking endurance.

Results

Old adults had greater fatigue-related reductions in peak velocity compared with young adults for both the elbow flexor and knee extensor muscles (P < 0.05) with no sex differences (P > 0.05). Old adults had greater variability of peak velocity during the knee extensor, but not during the elbow flexor fatiguing task. The age difference in fatigability was greater for the knee extensor muscles (35.9%) compared with elbow flexor muscles (9.7%, P < 0.05). Less fatigability of the knee extensor muscles was associated with greater walking endurance (r = − 0.34, P = 0.048) and balance (r = − 0.41, P = 0.014) among old adults.

Conclusions

An age-related increase in fatigability of a dynamic fatiguing task was greater for the knee extensor compared with the elbow flexor muscles in males and females, and greater fatigability was associated with lesser walking endurance and balance.

Comments

Published version. Experimental Gerontology, Vol. 87, No. A (January 2017): 74-83. DOI. © 2017 Elsevier. Used with permission.

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