The effects of antagonist moment on the resultant knee joint moment during isokinetic testing of the knee extensors

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Bibliographic Details
Title translated into German:Auswirkungen des Antagonisten-Kraftmoments auf das resultierende Kraftmoment im Kniegelenk bei isokinetischer Kraftmessung der Kniegelenkstrecker
Author:Kellis, E.; Baltzopoulos, V.
Published in:European journal of applied physiology
Published:76 (1997), 3 , S. 253-259, Lit.
Format: Publications (Database SPOLIT)
Publication Type: Journal article
Media type: Print resource
ISSN:1439-6319, 0301-5548
Online Access:
Identification number:PU199708206913

Author's abstract

The purpose of this study was to examine the effects of moment of antagonistic muscle on the resultant joint moment during isokinetic eccentric and concentric efforts of the knee extensors. Ten males performed maximum eccentric and concentric knee extension and flexion efforts on a Biodex dynamometer at 0.52 rad/s (30ø/s). Electromyographic (EMG) activity of vastus medialis and biceps femoris (hamstrings) was also recorded. The antagonistic moment of the hamstrings was determined by recording the integrated EMG (iEMG)/moment relationship at different levels of muscle effort. The iEMG/moment curves were fitted using second-degree polynomials. The polynomials were then used to predict the antagonistic moment exerted by the hamstrings from the antagonist iEMG. The antagonistic moment had a maximum of 42.92 Nm and 28.97 Nm under concentric and exxentric conditions respectively; paired t-tests indicated that this was a significant difference. These results indicate that the resultant joint moment of knee extensors is the result of both agonist and antagonist muscle activation. The greater anonist and antagonist muscle activation. The greater antagonist muscle activity under concentric activation conditions may be partly responsible for the lower resultant joint concentric moment of knee extensors compared with the corresponding eccentric activation. The antagonist moment significantly affects comparisons between the isokinetic moments and agonist EMG and in vitro force measurements under different testing (muscle action and angular velocity) conditions. Verf.-Referat