HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Corna, S Articles by Gresty, M A Search for Related Content PubMed PubMed Citation Articles by Corna, S Articles by Gresty, M A

Salvatore Maugeri Foundation, Division of Physical Therapy and Rehabilitation, Instituto di Ricovero E Cura A Carattere Scientifico, Novara, Italy.

1. We studied unloading and stretch responses in human neck muscle during manoeuvres in which the head pulled against a 2-3 kg weight which could be abruptly released or applied electromagnetically. 2. During head tracking in pitch, unloading of the weight induced inhibition of EMG in the contracting sternocleidomastoid at a mean latency of 24.9 ms in normal subjects and at 41 ms in bilateral labyrinthine-defective subjects, with antagonist (trapezius) excitation at 30.5 and 41.3 ms, respectively. During tracking in yaw, unloading induced inhibition in the contracting splenius capitis (SpC) at a mean latency of 20.4 ms in normal subjects and 25 ms in labyrinthine-defective subjects, with excitation in the antagonist SpC at 22.2 and 24 ms, respectively. 3. If subjects tried to resist an unexpected sideways tug on the head a burst occurred in the stretched SpC at a mean latency of 53.5 ms. When subjects relaxed there was excitation of the shortening of SpC at 75.9 ms, which assisted the imposed motion and is possibly a "defensive reflex".