Evaluation of voluntary and elicited dorsiflexor torque-angle
relations.
Koh, Timothy J., Walter Herzog.
Faculty of Kinesiology, University of Calgary, 2500 University
Drive N.W., Calgary, AB, CANADA
APStracts 2:0321A, 1995.
The purposes of this study were to determine the relative influence of
mechanical (muscle force and moment arm) and neural (activation)
factors on the shape of dorsiflexor torque-angle relations, and to
determine the interday reliability of measurements of such relations.
Dorsiflexor torque-angle relations produced with maximal voluntary
contractions (MVC) and with electrically elicited contractions
(twitch, 20 Hz tetanic, 40 Hz tetanic) were obtained for 7 male
subjects on two separate days. MVC torque-angle relations were
reproducible between days. Elicited relations were less reproducible
than the MVC relations, with the 40 Hz relation the most reproducible
of the elicited relations. The shapes of the MVC and elicited twitch
torque-angle relations were significantly different. The shapes of
the MVC, 20 and 40 Hz elicited relations were similar. The simplest
explanation for this latter finding is that the shape the MVC
relation is determined primarily by mechanical factors and is not
strongly dependent on neural factors. The results of this study may
affect the interpretation of comparisons of torque-angle relations
between subject groups or pre- and post-training.
Received 3 April 1995; accepted in final form 11 July 1995.
APS Manuscript Number A367-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 July 1995.