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Dynamic stiffness and damping of porcine muscle specimens
Medical Engineering & Physics 26 (2004) 261 www.elsevier.com/locate/medengphy
Letter to the Editor Dynamic stiffness and damping of porcine muscle specimens For their study of the mechanical properties of the muscles of the buttock, Aimedieu et al. removed cylindrical specimens from the gluteus maximus muscles of 3 pigs and subjected them to loading in their test apparatus [1]. The question needs to be asked: what is the relevance of their findings to the properties of muscles in vivo? Muscle fibres in vivo are invested in a network of blood and lymphatic vessels. The authors will have expelled the contents of these vessels, if not during the preparation of the specimen then certainly during the initial loading. Do they have some basis for assuming that the hydraulic effects of blood and lymph flowing into and out of loaded segments of the muscle are of no significance? The authors have noted the likelihood that postmortem changes, including rigor, could have modified their results. But a stimulus that results in stretch of an innervated muscle, particularly if it is of a vibratory nature, will also elicit a reflex contraction in vivo. The
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mechanical properties of a muscle in this state are unlikely to be emulated by a post-mortem specimen, whether in rigor or not. The title of the article accurately conveys the content. It seems highly doubtful, however, that the results bear any relationship to the mechanical behaviour of muscle in vivo. Stanley Salmons, University of Liverpool, British Heart Foundation Skeletal Muscle Assist Research Group, Department of Human Anatomy and Cell Biology, Liverpool L69 3GE, UK E-mail address: [email protected]
Reference [1] Aimedieu Jr P, Mitton D, Faure JP, Denninger L, Lavaste F. Dynamic stiffness and damping of porcine muscle specimens. Medical Engineering & Physics 2003;25:795–9.
Tel.: +44-151-794-5496; fax: +44-151-794-5517
1350-4533/$ - see front matter 2003 IPEM. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.medengphy.2003.11.003
Letter to the Editor Dynamic stiffness and damping of porcine muscle specimens For their study of the mechanical properties of the muscles of the buttock, Aimedieu et al. removed cylindrical specimens from the gluteus maximus muscles of 3 pigs and subjected them to loading in their test apparatus [1]. The question needs to be asked: what is the relevance of their findings to the properties of muscles in vivo? Muscle fibres in vivo are invested in a network of blood and lymphatic vessels. The authors will have expelled the contents of these vessels, if not during the preparation of the specimen then certainly during the initial loading. Do they have some basis for assuming that the hydraulic effects of blood and lymph flowing into and out of loaded segments of the muscle are of no significance? The authors have noted the likelihood that postmortem changes, including rigor, could have modified their results. But a stimulus that results in stretch of an innervated muscle, particularly if it is of a vibratory nature, will also elicit a reflex contraction in vivo. The
∗
mechanical properties of a muscle in this state are unlikely to be emulated by a post-mortem specimen, whether in rigor or not. The title of the article accurately conveys the content. It seems highly doubtful, however, that the results bear any relationship to the mechanical behaviour of muscle in vivo. Stanley Salmons, University of Liverpool, British Heart Foundation Skeletal Muscle Assist Research Group, Department of Human Anatomy and Cell Biology, Liverpool L69 3GE, UK E-mail address: [email protected]
Reference [1] Aimedieu Jr P, Mitton D, Faure JP, Denninger L, Lavaste F. Dynamic stiffness and damping of porcine muscle specimens. Medical Engineering & Physics 2003;25:795–9.
Tel.: +44-151-794-5496; fax: +44-151-794-5517
1350-4533/$ - see front matter 2003 IPEM. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.medengphy.2003.11.003