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Arch Phys Med Rehabil. 2001 Jul;82(7):973-8.

Characterization of the human quadriceps muscle in active elders.

Author information

1
Department of Physical Therapy, University of Delaware, Newark, DE 19716, USA. jensteve@udel.edu

Abstract

OBJECTIVE:

To compare muscle activation deficits and muscle physiology in older versus younger adults.

DESIGN:

A maximal volitional isometric contraction of the quadriceps muscle with burst-superimposition was used to assess strength and activation. In addition, force-frequency testing during fresh, fatigue, and recovery conditions and electrically elicited fatigue testing were performed.

SETTING:

Muscle performance laboratory.

PATIENTS:

Healthy, active young (age range, 20-28 yr) and older (age range, 66-83 yr) subjects.

MAIN OUTCOME MEASURES:

Torque production, activation of the quadriceps, F50 values from the force-frequency relationships (frequency at which 50% of the maximum normalized force is produced), and the average amount of fatigue.

RESULTS:

Older subjects were weaker (574.4 +/- 156 N) than younger subjects (900.9 +/- 295 N) and had significantly greater deficits in central activation in the quadriceps muscles (elderly = 95.5% activation; younger = 98.1% activation). The force-frequency curves for the elderly were to the left of the younger subjects for all 3 testing conditions. Aged muscles fatigued to the same extent as younger muscle (young = 49.8% +/- 2.6%, elderly = 51.1% +/- 2.8%).

CONCLUSIONS:

These results can be used to modify high-intensity strength training protocols designed to optimize sustainable strength gains in the elderly during rehabilitation.

PMID:
11441388
DOI:
10.1053/apmr.2001.23995
[Indexed for MEDLINE]
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