In vivo measurements of moment arm lengths of three elbow flexors at rest and during isometric contractions

Ryota Akagi, Soichiro Iwanuma, Satoru Hashizume, Hiroaki Kanehisa, Toshimasa Yanai, Yasuo Kawakami

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The purpose of this study was to determine in vivo moment arm lengths (MAs) of three elbow flexors at rest and during low- and relatively high-intensity contractions, and to examine the contraction intensity dependence of MAs at different joint positions. At 50°, 80° and 110° of elbow flexion, MAs of the biceps brachii, brachialis and brachioradialis were measured in 10 young men using sagittal images of the right arm obtained by magnetic resonance imaging, at rest and during 20% and 60% of isometric maximal voluntary elbow flexion. In most conditions, MAs increased with isometric contractions, which is presumably due to the contraction-induced thickening of the muscles. This phenomenon was especially evident in the flexed elbow positions. The influence of the contraction intensities on the increases in MAs varied across the muscles. These results suggest that in vivo measurements of each elbow flexor MA during contractions are essential to properly examine the effects on the interrelationships between elbow flexion torque and individual muscle forces.

Original languageEnglish
Pages (from-to)63-69
Number of pages7
JournalJournal of Applied Biomechanics
Volume28
Issue number1
Publication statusPublished - 2012 Feb
Externally publishedYes

Keywords

  • Biceps brachii
  • Brachialis
  • Brachioradialis
  • Center of rotation method
  • Magnetic resonance imaging
  • Muscle slackness

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Biophysics
  • Rehabilitation

Cite this

In vivo measurements of moment arm lengths of three elbow flexors at rest and during isometric contractions. / Akagi, Ryota; Iwanuma, Soichiro; Hashizume, Satoru; Kanehisa, Hiroaki; Yanai, Toshimasa; Kawakami, Yasuo.

In: Journal of Applied Biomechanics, Vol. 28, No. 1, 02.2012, p. 63-69.

Research output: Contribution to journalArticle

Akagi, R, Iwanuma, S, Hashizume, S, Kanehisa, H, Yanai, T & Kawakami, Y 2012, 'In vivo measurements of moment arm lengths of three elbow flexors at rest and during isometric contractions', Journal of Applied Biomechanics, vol. 28, no. 1, pp. 63-69.
Akagi, Ryota ; Iwanuma, Soichiro ; Hashizume, Satoru ; Kanehisa, Hiroaki ; Yanai, Toshimasa ; Kawakami, Yasuo. / In vivo measurements of moment arm lengths of three elbow flexors at rest and during isometric contractions. In: Journal of Applied Biomechanics. 2012 ; Vol. 28, No. 1. pp. 63-69.
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