Article Text


Interaction between voluntary contraction and tonic stretch reflex transmission in normal and spastic patients
  1. Peter D. Neilson1
  1. Division of Neurology, the Prince Henry Hospital, Sydney, Australia
  2. The School of Medicine, University of New South Wales, Sydney, Australia
  3. The School of Physics, University of New South Wales, Sydney, Australia


    Transmission characteristics of tonic stretch reflex (TSR) pathways in both normal and spastic patients have been measured during different levels of sustained voluntary contraction of the biceps brachii muscle. A cross-correlation technique of analysis was used to separate reflex responses from the total electromyographic activity. TSR transmission in normal subjects was observed to change with the level of voluntary contraction; sensitivity to stretch increased approximately three-fold as the subject stiffened the arm by simultaneously contracting flexor and extensor muscles. In contrast, TSR transmission did not alter during voluntary contraction in spastic patients. It is proposed that in spastic patients supraspinal modulation of reflex transmission is impaired because hypersensitive spinal reflexes short-circuit long loop pathways.

    Statistics from


    • 1 Centre Industries Research Scholar.

    Request permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.