The effect of ankle joint position and effort on quadriceps reflex sensitivity

Ing Shiou Hwang, Lawrence D. Abraham, Shih Wei Chou

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Objective: To investigate a possible ankle-knee synergy, experiments with normal subjects were performed to compare changes of the quadriceps motor pool excitability due to ankle position and effort. Methods: Vastus medialis H reflex amplitude was examined during ankle isometric contractions conditioned by different ankle positions (dorsiflexion, neutral, and plantarfiexion) with or without voluntary effort (either in the dorsiflexion or plantarflexion direction). Repeated measures ANOVAs were performed on the mean and standard deviation of the H peak-to-peak amplitude. Results: Mean vastus medialis H reflex amplitudes were significantly different among the trials of different ankle efforts (P<0.05), and significantly increased during plantarfiexion efforts. In contrast, mean vastus medialis H reflex amplitude did not vary with respect to changes of ankle position (P>0.05). Conclusions: The data suggest that (1) the position of the ankle joint did not significantly modify the excitability of the neuromotor pool of the VM muscle, in either static or active cases, and (2) the effort effect from the ankle joint on the VM neuromotor pool is most significant during ankle plantarfiexion effort. Possible mechanisms are central motor irradiation and peripheral force-dependent pathways from the ankle joint that influence the VM neuromotor pool. Copyright (C) 2000 Elsevier Science Ireland Ltd.

Original languageEnglish
Pages (from-to)1175-1183
Number of pages9
JournalClinical Neurophysiology
Issue number7
Publication statusPublished - 2000 Jul 1

All Science Journal Classification (ASJC) codes

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


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