Shortening during Stimulation vs. during Relaxation

How do the Costs Compare?
  • Fang Lou
  • N. A. Curtin
  • R. C. Woledge
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 453)


White muscle fibres from dogfish were used to investigate the energetic cost of shortening by fully active muscle and by relaxing muscle. The muscle preparation was tetanized for 0.6 s and shortened by 1 mm (about 15% L0) at 7 mm/s (about 30% Vo) either during stimulation or during relaxation. Isometric tetani at L0 were also investigated. Mechanical work was calculated from force and length change. Work + heat was taken as a measure of energetic cost. Both work and energetic cost were higher for shortening during stimulation than during relaxation. We also evaluated separately the work and heat associated with the contractile component and with the series elastic component. Work stored in the series elasticity could be completely recovered as external work when the shortening occurred during relaxation.


External Work Tetanic Stimulation Contractile Component Series Elastic Component White Muscle Fibre 


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  1. 1.
    Bone, Q. On the function of the two types of myotomal muscle fibres in elasmobranch fish. J. Mar. Biol. Ass. U.K., 46, 321–349 (1966).CrossRefGoogle Scholar
  2. 2.
    Mos, W., Roberts, B.L. and Williamson, R. Activity patterns of motoneurons in the spinal dogfish in relation to changing fictive locomotion. Phil. Trans. R. Soc. Lond B., 330, 329–339 (1990).CrossRefGoogle Scholar
  3. 3.
    Potma, E.J., Stienen, G J.M., Barends, J.P.F. and Elzinga, G. Myofibrillar ATPase activity and mechanical performance of skinned fibres from rabbit Psoas muscle. J. Physiol. Lond. 474, 303–317 (1994).PubMedGoogle Scholar
  4. 4.
    Curtin, N.A. & Woledge, R.C. Power at the expense of efficiency in contraction of white muscle fibres from dogfish, Scyliorhinus canicula. J. Exp. Biol. 199, 593–601 (1996).Google Scholar
  5. 5.
    Woledge, R.C, Curtin, N.A. & Homsher, R.C. Energetic Aspects of Muscle Contraction (Academic Press, London, 1985).Google Scholar
  6. 6.
    Alexander, R. McN. Elastic Mechanisms in Animal Movement (Cambridge University Press, Cambridge, 1988).Google Scholar
  7. 7.
    Cannell, M.B. The effect of tetanus duration on the free calcium concentration during relaxation of frog skeletal muscle fibres. J. Physiol. Lond. 376, 203–218 (1986).PubMedGoogle Scholar
  8. 8.
    Caputo, C., Edman, K.A.P., Lou, F. & Sun, Y.-B. Variation in myoplasmic Ca2+ concentration during contraction and relaxation studied by the indicator fluo-3 in frog muscle fibres. J. Physiol. Lond. 478, 137–148 (1994).PubMedGoogle Scholar
  9. 9.
    Edman, K.A.P. Mechanical deactivation induced by active shortening in isolated muscle fibres of the frog. J. Physiol. Lond. 246, 255–275 (1975).PubMedGoogle Scholar

Copyright information

© Plenum Press, New York 1998

Authors and Affiliations

  • Fang Lou
    • 1
  • N. A. Curtin
    • 1
  • R. C. Woledge
    • 2
  1. 1.Department of Cellular and Integrative Biology Division of Biomedical SciencesImperial College School of MedicineLondonUK
  2. 2.Institute of Human PerformanceUniversity College London Royal National Orthopaedic Hospital TrustBrockley Hill, Stanmore, MiddlesexUK

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