European Journal of Applied Physiology

, Volume 106, Issue 5, pp 769–774

Evoked tetanic torque and activation level explain strength differences by side

Short Communication

DOI: 10.1007/s00421-009-1057-y

Cite this article as:
Krishnan, C. & Williams, G.N. Eur J Appl Physiol (2009) 106: 769. doi:10.1007/s00421-009-1057-y


Previous studies have demonstrated that healthy young people typically have side-to-side differences in knee strength of about 10% when the peak torque generated by the stronger leg is contrasted with that of the weaker leg. However, the mechanisms responsible for side-to-side differences in knee strength have not been clearly defined. The current study tested the hypothesis that side-to-side knee extensor strength differences are explained by inter-limb variations in voluntary activation, antagonistic hamstrings activity, and electrically evoked torque at rest. Twenty-two volunteers served as subjects. Side-to-side differences in quadriceps activation and electrically evoked knee extensor torque explained 69% of the strength differences by side. Antagonistic hamstrings activity did not contribute significantly. The results suggest both central and peripheral mechanisms contribute to inter-limb variations in strength.


Central activation Antagonist muscle activity Knee strength Contractile properties ITT 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Graduate Program in Physical Therapy and Rehabilitation ScienceUniversity of IowaIowa CityUSA
  2. 2.University of Iowa Sports Medicine CenterUniversity of IowaIowa CityUSA
  3. 3.1-152 MEB, Musculoskeletal Biomechanics and Sports Medicine Research Laboratory, Carver College of MedicineUniversity of IowaIowa CityUSA

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