Leg stiffness and electromyography of knee extensors/flexors: Comparison between older and younger adults during stair descent

Miao Ju Hsu, Shun Hwa Wei, Young Hue Yu, Ya Ju Chang*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

20 Scopus citations

Abstract

This study investigated differences in knee extensor/ flexor electromyography (EMG), leg loading rate, and leg stiffness in older and younger men during stair descent. Sixteen older men (mean +/- standard deviation [SD] = 72 +/-4.5 years) and sixteen younger men (mean +/- SD = 21.2 +/-0.5 years) were recruited. The EMG signals were recorded from the rectus femoris and the biceps femoris, while an electrogoniometer measured knee joint angle changes, and a force platform recorded the ground reaction forces (GRFs). We calculated leg stiffness by dividing the first peak GRF by the corresponding leg displacement. We used the Student's t-test to examine group differences. Results showed that the older subjects had 78.6% higher preactivated EMG values in the knee extensor and 128% greater coactivity in the knee extensors/ flexors in the prelanding phase. At the impact phase, we observed leg stiffness to be 26.6% greater in the older than the younger subjects. The older subjects needed 94.6% more support time in performing push-off and also developed a compensatory strategy in stair descent, which altered the scaling of muscle preactivity and increased leg stiffness.

Original languageEnglish
Pages (from-to)429-435
Number of pages7
JournalJournal of Rehabilitation Research and Development
Volume44
Issue number3
DOIs
StatePublished - 2007

Keywords

  • Coactivation
  • EMG
  • Elderly
  • Knee extensor/flexor
  • Leg loading rate
  • Leg stiffness
  • Preactivation
  • Rehabilitation
  • Stair descent
  • Stair walking

Fingerprint

Dive into the research topics of 'Leg stiffness and electromyography of knee extensors/flexors: Comparison between older and younger adults during stair descent'. Together they form a unique fingerprint.

Cite this