Mechanical properties of the elbow joint in spastic hemiparetic stroke subjects

M. M. Mirbagheri*, R. Harvey, W. Z. Rymer

*Corresponding author for this work

Research output: Contribution to journalConference article

1 Scopus citations


A parallel-cascade system identification technique was used to measure dynamic elbow stiffness in hemiparetic stroke subjects. Modulation of intrinsic and reflex stiffness of elbow flexor muscles was studied by applying perturbations to the elbow at different initial joint angles with subjects' muscles relaxed. Intrinsic stiffness increased smoothly from mid-flexion to mid-extension and increased sharply at the extreme range of motion in both spastic and contralateral (control) sides. However, intrinsic stiffness was significantly larger in spastic than control side. Reflex stiffness increased monotonically from full flexion to mid-extension then decreased at full extension in both sides. However, reflex stiffness was significantly larger on the spastic than control side; the difference reached its maximum at the middle of elbow extension. The intrinsic stiffness estimates were consistent in all stroke subjects, whereas enhanced reflex stiffness was significant in only a portion of the stroke cohort. These findings suggest that enhanced intrinsic stiffness of passive tissues is a major mechanical abnormality in stroke subjects.

Original languageEnglish (US)
Pages (from-to)2449-2450
Number of pages2
JournalAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
StatePublished - Dec 1 2002
EventProceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS) - Houston, TX, United States
Duration: Oct 23 2002Oct 26 2002

ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

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