In vivo determination of the direction of rotation and moment-angle relationship of individual elbow muscles

Li-Qun Zhang, J. Butler, T. Nishida, Gordon M Nuber, H. Huang, William Z Rymer

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The direction of rotation (DOR) of individual elbow muscles, defined as the direction in which a muscle rotates the forearm relative to the upper arm in three-dimensional space, was studied in vivo as a function of elbow flexion and forearm rotation. Electrical stimulation was used to activate an individual muscle selectively, and the resultant flexion-extension, supination-pronation, and varus-valgus moments were used to determine the DOR. Furthermore, multi-axis moment-angle relationships of individual muscles were determined by stimulating the muscle at a constant submaximal level across different joint positions, which was assumed to result in a constant level of muscle activation. The muscles generate significant moments about axes other than flexion-extension, which is potentially important for actively controlling joint movement and maintaining stability about all axes. Both the muscle DOR and the multi axis moments vary with the joint position systematically. Variations of the DOR and moment-angle relationship across muscle twitches of different amplitudes in a subject were small, while there were considerable variations between subjects.

Original languageEnglish (US)
Pages (from-to)625-633
Number of pages9
JournalJournal of Biomechanical Engineering
Volume120
Issue number5
DOIs
StatePublished - Jan 1 1998

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physiology (medical)

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