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. 1973 Dec 1;62(6):663–676. doi: 10.1085/jgp.62.6.663

Energetics of Shortening Muscles in Twitches and Tetanic Contractions

I. A Reinvestigation of Hill's Concept of the Shortening Heat

Earl Homsher 1, Jack A Rall 1
PMCID: PMC2226140  PMID: 4548713

Abstract

Shortening heat was defined by Hill as the "difference between heat produced when shortening occurs and that produced in a similar contraction without shortening." For the tetanus the "similar contraction" was an isometric one at or near lo. By contrast, in a twitch the "similar contraction" was one in which only activation heat was produced. The applicability of Hill's concept of the shortening heat has been reexamined in both the twitch and tetanus of Rana pipiens semitendinosus muscles. Results of this investigation confirm the existence of an extra heat production accompanying shortening in the twitch and tetanus. In both cases, this shortening heat was proportional to distance shortened and relative afterload. However, at a given afterload the amount of shortening heat produced per distance shortened was greater in the twitch than the tetanus. This difference suggests that the base lines or "similar contractions" employed for the twitch and tetanus are not equivalent. The discrepancy is not remedied by utilizing in the tetanus the activation heat as the myothermic baseline and suggests that some heat producing factor(s) has been omitted in Hill's formulation of the shortening heat. Finally, the existence of Hill's feedback heat, an energy liberation associated with the presence of tension during mechanical relaxation, was not confirmed. This result strongly indicates that relaxation is energetically passive.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aubert X., Lebacq J. The heat of shortening during the plateau of tetanic contraction and at the end of relaxation. J Physiol. 1971 Jul;216(1):181–200. doi: 10.1113/jphysiol.1971.sp009517. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Brady A. J. Onset of contractility in cardiac muscle. J Physiol. 1966 Jun;184(3):560–580. doi: 10.1113/jphysiol.1966.sp007931. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. CARLSON F. D., HARDY D. J., WILKIE D. R. Total energy production and phosphocreatine hydrolysis in the isotonic twitch. J Gen Physiol. 1963 May;46:851–882. doi: 10.1085/jgp.46.5.851. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fenn W. O. A quantitative comparison between the energy liberated and the work performed by the isolated sartorius muscle of the frog. J Physiol. 1923 Dec 28;58(2-3):175–203. doi: 10.1113/jphysiol.1923.sp002115. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Fenn W. O. The relation between the work performed and the energy liberated in muscular contraction. J Physiol. 1924 May 23;58(6):373–395. doi: 10.1113/jphysiol.1924.sp002141. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. HILL A. V. THE EFFECT OF LOAD ON THE HEAT OF SHORTENING OF MUSCLE. Proc R Soc Lond B Biol Sci. 1964 Jan 14;159:297–318. doi: 10.1098/rspb.1964.0004. [DOI] [PubMed] [Google Scholar]
  7. HILL A. V. THE EFFECT OF TENSION IN PROLONGING THE ACTIVE STATE IN A TWITCH. Proc R Soc Lond B Biol Sci. 1964 Mar 17;159:589–595. doi: 10.1098/rspb.1964.0021. [DOI] [PubMed] [Google Scholar]
  8. HILL A. V. THE VARIATION OF TOTAL HEAL PRODUCTION IN A TWITCH WITH VELOCITY OF SHORTENING. Proc R Soc Lond B Biol Sci. 1964 Mar 17;159:596–605. doi: 10.1098/rspb.1964.0022. [DOI] [PubMed] [Google Scholar]
  9. HILL A. V. The heat of activation and the heat of shortening in a muscle twitch. Proc R Soc Lond B Biol Sci. 1949 Jun 23;136(883):195–211. doi: 10.1098/rspb.1949.0019. [DOI] [PubMed] [Google Scholar]
  10. HILL A. V., WOLEDGE R. C. An examination of absolute values in myothermic measurements. J Physiol. 1962 Jul;162:311–333. doi: 10.1113/jphysiol.1962.sp006935. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Homsher E., Mommaerts W. F., Ricchiuti N. V., Wallner A. Activation heat, activation metabolism and tension-related heat in frog semitendinosus muscles. J Physiol. 1972 Feb;220(3):601–625. doi: 10.1113/jphysiol.1972.sp009725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Kushmerick M. J., Larson R. E., Davies R. E. The chemical energetics of muscle contraction. I. Activation heat, heat of shortening and ATP utilization for activation-relaxation processes. Proc R Soc Lond B Biol Sci. 1969 Dec 23;174(1036):293–313. doi: 10.1098/rspb.1969.0095. [DOI] [PubMed] [Google Scholar]
  13. MOMMAERTS W. F., SERAYDARIAN K., MARECHAL G. Work and chemical change in isotonic muscular contractions. Biochim Biophys Acta. 1962 Feb 12;57:1–12. doi: 10.1016/0006-3002(62)91071-5. [DOI] [PubMed] [Google Scholar]
  14. Smith I. C. Energetics of activation in frog and toad muscle. J Physiol. 1972 Feb;220(3):583–599. doi: 10.1113/jphysiol.1972.sp009724. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Wilkie D. R. Heat work and phosphorylcreatine break-down in muscle. J Physiol. 1968 Mar;195(1):157–183. doi: 10.1113/jphysiol.1968.sp008453. [DOI] [PMC free article] [PubMed] [Google Scholar]

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