Show simple item record

dc.contributor.authorLichtwark, Glen
dc.contributor.authorC. Watson, Johanna
dc.contributor.authorMavrommatis, Sophia
dc.contributor.authorM. Wilson, Alan
dc.date.accessioned2017-05-03T13:49:00Z
dc.date.available2017-05-03T13:49:00Z
dc.date.issued2009
dc.date.modified2010-07-27T07:19:07Z
dc.identifier.issn00220949
dc.identifier.doi10.1242/jeb.027995
dc.identifier.urihttp://hdl.handle.net/10072/30658
dc.description.abstractThe equine biceps brachii (biceps) initiates rapid limb protraction through a catapult mechanism. Elastic strain energy is slowly stored in an internal tendon and is then rapidly released to protract the forelimb. The muscle fibres are short, have little scope for length change and can therefore only shorten slowly compared with the speed at which the whole muscle must shorten, which makes them poor candidates for driving rapid limb protraction. We suggest that the muscle fibres in the biceps act to modulate the elastic energy output of the muscle-tendon unit (MTU) to meet the demands of locomotion under different conditions. We hypothesise that more elastic strain energy is stored and released from the biceps MTU during higher speed locomotion to accommodate the increase in energy required to protract the limb and that this can be achieved by varying the length change and activation conditions of the muscle. We examined the work performed by the biceps during trot and canter using an inverse dynamics analysis (IDA). We then used excised biceps muscles to determine how much work could be performed by the muscle in active and passive stretch-shorten cycles. A muscle model was developed to investigate the influence of changes in activation parameters on energy storage and energy return from the biceps MTU. Increased biceps MTU length change and increased work performed by the biceps MTU were found at canter compared with at trot. More work was performed by the ex vivo biceps MTU following activation of the muscle and by increasing muscle length change. However, the ratio of active to passive work diminished with increasing length change. The muscle model demonstrated that duration and timing of activation during stretch-shorten cycles could modulate the elastic energy storage and return from the biceps. We conclude that the equine biceps MTU acts as a tuneable spring and the contractile component functions to modulate the energy required for rapid forelimb protraction at different speeds.
dc.description.peerreviewedYes
dc.description.publicationstatusYes
dc.languageEnglish
dc.language.isoeng
dc.publisherThe Company of Biologists Ltd.
dc.publisher.placeUnited Kingdom
dc.relation.ispartofstudentpublicationN
dc.relation.ispartofpagefrom2454
dc.relation.ispartofpageto2463
dc.relation.ispartofissue15
dc.relation.ispartofjournalThe Journal of Experimental Biology
dc.relation.ispartofvolume212
dc.rights.retentionY
dc.subject.fieldofresearchBiological sciences
dc.subject.fieldofresearchOther biological sciences not elsewhere classified
dc.subject.fieldofresearchBiomedical and clinical sciences
dc.subject.fieldofresearchcode31
dc.subject.fieldofresearchcode319999
dc.subject.fieldofresearchcode32
dc.titleIntensity of activation and timing of deactivation modulate elastic energy storage and release in a pennate muscle and account for gait-specific initiation of limb protraction in the horse
dc.typeJournal article
dc.type.descriptionC1 - Articles
dc.type.codeC - Journal Articles
gro.facultyGriffith Health, School of Rehabilitation Sciences
gro.rights.copyright© 2009 Company of Biologists Ltd. Self-archiving of the author-manuscript version is not yet supported by this publisher. Please refer to the journal link for access to the definitive, published version or contact the authors for more information.
gro.date.issued2009
gro.hasfulltextNo Full Text
gro.griffith.authorLichtwark, Glen A.


Files in this item

FilesSizeFormatView

There are no files associated with this item.

This item appears in the following Collection(s)

  • Journal articles
    Contains articles published by Griffith authors in scholarly journals.

Show simple item record