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The torque–velocity relationship in large human muscles: maximum voluntary versus electrically stimulated behaviour

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posted on 2013-06-18, 13:51 authored by Matthew PainMatthew Pain, Fraser Young, Jinwoo Kim, Steph ForresterSteph Forrester
The in vivo maximum voluntary torque–velocity profile for large muscle groups differs from the in vitro tetanic profile with lower than expected eccentric torques. Using sub-maximal transcutaneous electrical stimulation has given torque–velocity profiles with an eccentric torque plateau ~1.4 times the isometric value. This is closer to, but still less than, the in vitro tetanic profiles with plateaus between 1.5 and 1.9 times isometric. This study investigated the maximum voluntary and sub-maximum transcutaneous electrical stimulated torque–angle–angular velocity profiles for the knee extensors and flexors in a group of healthy males. Fifteen male subjects performed maximum voluntary and submaximum electrically stimulated (~40% for extensors and ~20% for flexors) eccentric and concentric knee extension and flexions on an isovelocity dynamometer at velocities ranging from ±50° s-1 to ±400° s-1. The ratio of peak eccentric to peak isometric torque (Tecc/T0) was compared between the maximum voluntary and electrically stimulated conditions for both extensors and flexors, and between muscle groups. Under maximum voluntary conditions the peak torque ratio, Tecc/T0, remained close to 1 (0.9 – 1.2) while for the electrically stimulated conditions it was significantly higher (1.4 – 1.7 ; p<0.001) and within the range of tetanic values reported from in vitro studies. In all but one case there was no significant difference in ratios between the extensors and flexors. The results showed that even the largest muscle groups have an intrinsic Tecc/T0 comparable with in vitro muscle tests, and it can be ascertained from appropriate in vivo testing.

History

School

  • Sport, Exercise and Health Sciences

Citation

PAIN, M.T.G. ... et al, 2013. The torque–velocity relationship in large human muscles: maximum voluntary versus electrically stimulated behaviour. Journal of Biomechanics, 46 (4), pp.645-650.

Publisher

© Elsevier

Version

  • AM (Accepted Manuscript)

Publication date

2013

Notes

NOTICE: this is the author’s version of a work that was accepted for publication in the Journal of Biomechanics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published at: http://dx.doi.org/10.1016/j.jbiomech.2012.11.052

Language

  • en