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: 98/6/2087    most recent 01217.2004v1 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 ISI 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 ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Oskouei, A. E. Articles by Herzog, W. Search for Related Content PubMed PubMed Citation Articles by Oskouei, A. E. Articles by Herzog, W.

Observations on force enhancement in submaximal voluntary contractions of human adductor pollicis muscle

Human Performance Laboratory, University of Calgary, Calgary, Alberta, Canada

Submitted 29 October 2004 ; accepted in final form 8 February 2005

It has been observed consistently and is well accepted that the steady-state isometric force after active muscle stretch is greater than the corresponding isometric force for electrically stimulated muscles and maximal voluntary contractions. However, this so-called force enhancement has not been studied for submaximal voluntary efforts; therefore, it is not known whether this property affects everyday movements. The purpose of this study was to determine whether there was force enhancement during submaximal voluntary contractions. Human adductor pollicis muscles (n = 17) were studied using a custom-built dynamometer, and both force and activation were measured while muscle activation and force were controlled at a level of 30% of maximal voluntary contraction. The steady-state isometric force and activation after active stretch were compared with the corresponding values obtained during isometric reference contractions. There was consistent and reliable force enhancement in 8 of the 17 subjects, whereas there was no force enhancement in the remaining subjects. Subjects with force enhancement had greater postactivation potentiation and a smaller resistance to fatigue in the adductor pollicis. We conclude from these results that force enhancement exists during submaximal voluntary contractions in a subset of the populations and suggest that it may affect everyday voluntary movements in this subset. On the basis of follow-up testing, it appears that force enhancement during voluntary contractions is linked to potentiation and fatigue resistance and therefore possibly to the fiber-type distribution in the adductor pollicis muscle.

muscle activation; fast-twitch fibers; postactivation potentiation

This article has been cited by other articles:

				G. Zhi, J. W. Ryder, J. Huang, P. Ding, Y. Chen, Y. Zhao, K. E. Kamm, and J. T. Stull Myosin light chain kinase and myosin phosphorylation effect frequency-dependent potentiation of skeletal muscle contraction PNAS, November 29, 2005; 102(48): 17519 - 17524. [Abstract] [Full Text] [PDF]