QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online September 9, 2003

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted 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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Kaya, M. Articles by Herzog, W. Search for Related Content PubMed PubMed Citation Articles by Kaya, M. Articles by Herzog, W. Social Bookmarking                         What's this?

The Journal of Experimental Biology 206, 3645-3655 (2003)
doi: 10.1242/jeb.00544

Coordination of medial gastrocnemius and soleus forces during cat locomotion

Motoshi Kaya, Tim Leonard and Walter Herzog^*

Faculty of Kinesiology, Human Performance Laboratory, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada, T2N 1N4

^* Author for correspondence (e-mail: walter{at}kin.ucalgary.ca)

Accepted 16 June 2003

We studied force-sharing behavior between the cat medial gastrocnemius (MG) and soleus (SOL) muscles by direct measurement of the muscle forces and electromyographic activities (EMGs), muscle lengths, speeds of contraction, joint kinematics and kinetics, for a variety of locomotor conditions. Previous studies suggested that the modulation of MG force and activation is associated with movement demands, while SOL force and activation remain nearly constant. However, no systematic, quantitative analysis has been done to evaluate the degree of (possible) modulation of SOL force and activation across a range of vastly different locomotor conditions. In the present study, we investigated the effects of speed and intensity of locomotion on the modulation of SOL force and EMG activity, based on quantitative, statistical analyses. We also investigated the hypothesis that MG forces are primarily associated with MG activation for changing movement demands, while SOL forces are primarily associated with the contractile conditions, rather than activation. Seven cats were trained to walk, trot and gallop at different speeds on a motor-driven treadmill, and to walk up and down different slopes on a walkway. Statistical analysis suggested that SOL activation (EMG activity) significantly increased with increasing speeds and intensities of locomotion, while SOL forces remained constant in these situations. MG forces and EMG activities, however, both increased with increasing speeds and intensities of locomotion. We conclude from these results that SOL is not maximally activated at slow walking, as suggested in the literature, and that its force remains nearly constant for a range of locomotor conditions despite changes in EMG activity. Therefore, SOL forces appear to be affected substantially by the changing contractile conditions associated with changing movement demands. In contrast, MG peak forces correlated well with EMG activities, suggesting that MG forces are primarily associated with activation while its contractile conditions play a minor role for the movement conditions tested here.

Key words: muscle coordination, contractile condition, medial gastrocnemius muscle, soleus muscle, cat, uphill walking, downhill walking

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				H. Maas, R. J. Gregor, E. F. Hodson-Tole, B. J. Farrell, and B. I. Prilutsky Distinct muscle fascicle length changes in feline medial gastrocnemius and soleus muscles during slope walking J Appl Physiol, April 1, 2009; 106(4): 1169 - 1180. [Abstract] [Full Text] [PDF]

				J. M. Wakeling and T. Horn Neuromechanics of Muscle Synergies During Cycling J Neurophysiol, February 1, 2009; 101(2): 843 - 854. [Abstract] [Full Text] [PDF]

				T. E. Higham and A. A. Biewener Integration within and between muscles during terrestrial locomotion: effects of incline and speed J. Exp. Biol., July 15, 2008; 211(14): 2303 - 2316. [Abstract] [Full Text] [PDF]

				F. E. Nelson and T. J. Roberts Task-dependent force sharing between muscle synergists during locomotion in turkeys J. Exp. Biol., April 15, 2008; 211(8): 1211 - 1220. [Abstract] [Full Text] [PDF]

				M. Kaya, T. R Leonard, and W. Herzog Premature deactivation of soleus during the propulsive phase of cat jumping J R Soc Interface, April 6, 2008; 5(21): 415 - 426. [Abstract] [Full Text] [PDF]

				A. M. Gabaldon, F. E. Nelson, and T. J. Roberts Relative shortening velocity in locomotor muscles: turkey ankle extensors operate at low V/Vmax Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2008; 294(1): R200 - R210. [Abstract] [Full Text] [PDF]

				J. M Wakeling, K. Uehli, and A. I Rozitis Muscle fibre recruitment can respond to the mechanics of the muscle contraction J R Soc Interface, August 22, 2006; 3(9): 533 - 544. [Abstract] [Full Text] [PDF]

				R. J. Gregor, D. W. Smith, and B. I. Prilutsky Mechanics of Slope Walking in the Cat: Quantification of Muscle Load, Length Change, and Ankle Extensor EMG Patterns J Neurophysiol, March 1, 2006; 95(3): 1397 - 1409. [Abstract] [Full Text] [PDF]

				S. J. Wickler, D. F. Hoyt, A. A. Biewener, E. A. Cogger, and K. L. De La Paz In vivo muscle function vs speed II. Muscle function trotting up an incline J. Exp. Biol., March 15, 2005; 208(6): 1191 - 1200. [Abstract] [Full Text] [PDF]

				J. M. Donelan and K. G. Pearson Contribution of Force Feedback to Ankle Extensor Activity in Decerebrate Walking Cats J Neurophysiol, October 1, 2004; 92(4): 2093 - 2104. [Abstract] [Full Text] [PDF]