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Agonist muscle activity and antagonist muscle co-activity levels during standardized isotonic and isokinetic knee extensions.
J Electromyogr Kinesiol. 2009 Jun; 19(3):449-58.JE

Abstract

This study aimed to analyze the effects of the contraction mode (isotonic vs. isokinetic concentric conditions), the joint angle and the investigated muscle on agonist muscle activity and antagonist muscle co-activity during standardized knee extensions. Twelve healthy adult subjects performed three sets of isotonic knee extensions at 40% of their maximal voluntary isometric torque followed by three sets of maximal isokinetic knee extensions on an isokinetic dynamometer. For each set, the mean angular velocity and the total external amount of work performed were standardized during the two contraction modes. Surface electromyographic activity of vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), semitendinosus (ST) and biceps femoris (BF) muscles was recorded. Root mean square values were then calculated for each 10 degrees between 85 degrees and 45 degrees of knee extension (0 degrees =horizontal position). Results show that agonist muscle activity and antagonist muscle co-activity levels are significantly greater in isotonic mode compared to isokinetic mode. Quadriceps activity and hamstrings co-activity are significantly lower at knee extended position in both contraction modes. Considering agonist muscles, VL reveals a specific pattern of activity compared to VM and RF; whereas considering hamstring muscles, BF shows a significantly higher co-activity than ST in both contraction modes. Results of this study confirmed our hypothesis that higher quadriceps activity is required during isotonic movements compared to isokinetic movements leading to a higher hamstrings co-activity.

Authors+Show Affiliations

Université de Nantes, Nantes Atlantique Universités, Laboratoire Motricité, Interactions, Performance, JE 2438, UFR STAPS 25 bis Bd Guy Mollet - BP 72206, 44 322 Nantes Cedex 3, France. anthony.remaud@univ-nantes.frNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18093843

Citation

Remaud, Anthony, et al. "Agonist Muscle Activity and Antagonist Muscle Co-activity Levels During Standardized Isotonic and Isokinetic Knee Extensions." Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology, vol. 19, no. 3, 2009, pp. 449-58.
Remaud A, Cornu C, Guével A. Agonist muscle activity and antagonist muscle co-activity levels during standardized isotonic and isokinetic knee extensions. J Electromyogr Kinesiol. 2009;19(3):449-58.
Remaud, A., Cornu, C., & Guével, A. (2009). Agonist muscle activity and antagonist muscle co-activity levels during standardized isotonic and isokinetic knee extensions. Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology, 19(3), 449-58.
Remaud A, Cornu C, Guével A. Agonist Muscle Activity and Antagonist Muscle Co-activity Levels During Standardized Isotonic and Isokinetic Knee Extensions. J Electromyogr Kinesiol. 2009;19(3):449-58. PubMed PMID: 18093843.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Agonist muscle activity and antagonist muscle co-activity levels during standardized isotonic and isokinetic knee extensions. AU - Remaud,Anthony, AU - Cornu,Christophe, AU - Guével,Arnaud, Y1 - 2008/02/21/ PY - 2007/06/08/received PY - 2007/10/26/revised PY - 2007/11/02/accepted PY - 2007/12/21/pubmed PY - 2009/6/3/medline PY - 2007/12/21/entrez SP - 449 EP - 58 JF - Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology JO - J Electromyogr Kinesiol VL - 19 IS - 3 N2 - This study aimed to analyze the effects of the contraction mode (isotonic vs. isokinetic concentric conditions), the joint angle and the investigated muscle on agonist muscle activity and antagonist muscle co-activity during standardized knee extensions. Twelve healthy adult subjects performed three sets of isotonic knee extensions at 40% of their maximal voluntary isometric torque followed by three sets of maximal isokinetic knee extensions on an isokinetic dynamometer. For each set, the mean angular velocity and the total external amount of work performed were standardized during the two contraction modes. Surface electromyographic activity of vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), semitendinosus (ST) and biceps femoris (BF) muscles was recorded. Root mean square values were then calculated for each 10 degrees between 85 degrees and 45 degrees of knee extension (0 degrees =horizontal position). Results show that agonist muscle activity and antagonist muscle co-activity levels are significantly greater in isotonic mode compared to isokinetic mode. Quadriceps activity and hamstrings co-activity are significantly lower at knee extended position in both contraction modes. Considering agonist muscles, VL reveals a specific pattern of activity compared to VM and RF; whereas considering hamstring muscles, BF shows a significantly higher co-activity than ST in both contraction modes. Results of this study confirmed our hypothesis that higher quadriceps activity is required during isotonic movements compared to isokinetic movements leading to a higher hamstrings co-activity. SN - 1873-5711 UR - https://www.unboundmedicine.com/medline/citation/18093843/Agonist_muscle_activity_and_antagonist_muscle_co_activity_levels_during_standardized_isotonic_and_isokinetic_knee_extensions_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1050-6411(07)00184-8 DB - PRIME DP - Unbound Medicine ER -