Effects of fiber type on force depression after active shortening in skeletal muscle

dc.contributor.authorJoumaa, Vénus
dc.contributor.authorPower, Geoffrey A.
dc.contributor.authorHisey, Brandon
dc.contributor.authorCaicedo, A.
dc.contributor.authorStutz, J.
dc.contributor.authorHerzog, Walter
dc.date.accessioned2018-09-19T20:35:59Z
dc.date.available2018-09-19T20:35:59Z
dc.date.issued2015-07-16
dc.description.abstractThe aim of this study was to investigate force depression in Type I and Type II muscle fibers. Experiments were performed using skinned fibers from rabbit soleus and psoas muscles. Force depression was quantified after active fiber shortening from an average sarcomere length (SL) of 3.2µ m to an average SL of 2.6 µm at an absolute speed of 0.115f iber length/s and at a relative speed corresponding to 17% of the unloaded shortening velocity (V0) in each type of fibers. Force decay and mechanical work during shortening were also compared between fiber types. After mechanical testing, each fiber was subjected to myosin heavy chain (MHC) analysis in order to confirm its type (Type I expressing MHC I, and Type II expressing MHC IId). Type II fibers showed greater steady-state force depression after active shortening at a speed of 0.115 fiber length/s than Type I fibers (14.5±1.5% versus 7.8±1.7%). Moreover, at this absolute shortening speed, Type I fibers showed a significantly greater rate of force decay during shortening and produced less mechanical work than Type II fibers. When active shortening was performed at the same relative speed (17% V0), the difference in force depression between fiber types was abolished. These results suggest that no intrinsic differences were at the origin of the disparate force depressions observed in Type I and Type II fibers when actively shortened at the same absolute speed, but rather their distinct force-velocity relationships.en_US
dc.identifier.citationJoumaa, V., Power, G. A., Hisey, B., Caicedo, A., Stutz, J., & Herzog, W. (2015). Effects of fiber type on force depression after active shortening in skeletal muscle. Journal of Biomechanics, 48(10), 1687–1692. https://doi.org/10.1016/j.jbiomech.2015.05.023en_US
dc.identifier.doihttp://dx.doi.org/10.1016/j.jbiomech.2015.05.023en_US
dc.identifier.issn1873-2380
dc.identifier.urihttp://hdl.handle.net/1880/107774
dc.language.isoenen_US
dc.publisherElsevieren_US
dc.publisher.departmentHuman Performance Laben_US
dc.publisher.facultyKinesiologyen_US
dc.publisher.hasversionPost-printen_US
dc.publisher.institutionUniversity of Calgaryen_US
dc.publisher.policyhttps://www.elsevier.com/about/policies/copyrighten_US
dc.rightsUnless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.en_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0en_US
dc.subjectcross-bridge theoryen_US
dc.subjectfast twitchen_US
dc.subjecthistory dependenceen_US
dc.subjectMHCen_US
dc.subjectslow-twitchen_US
dc.titleEffects of fiber type on force depression after active shortening in skeletal muscleen_US
dc.typejournal articleen_US
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