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dc.contributor.authoraf Klint, R.en_US
dc.contributor.authorCronin, N.en_US
dc.contributor.authorIshikawa, M.en_US
dc.contributor.authorSinkjaer, T.en_US
dc.contributor.authorGrey, M.en_US
dc.date.accessioned2017-04-24T13:24:48Z
dc.date.available2017-04-24T13:24:48Z
dc.date.issued2010en_US
dc.date.modified2010-10-07T04:08:35Z
dc.identifier.issn00223077en_US
dc.identifier.doi10.1152/jn.00852.2009en_AU
dc.identifier.urihttp://hdl.handle.net/10072/34092
dc.description.abstractPlantar flexor series elasticity can be used to dissociate muscle-fascicle and muscle-tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to ᳰ in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force also unloaded the plantar flexor muscles. The soleus muscle fascicles shortened with a minimum delay of 14 ms. Small variations in platform inclination produced significant changes in triceps surae muscle activity; EMG increased when stepping on an inclined surface and decreased when stepping on a declined surface. This sensory modulation of the locomotor output was concomitant with changes in triceps surae muscle fascicle and gastrocnemius tendon length. Assuming that afferent activity correlates to these mechanical changes, our results indicate that within-step sensory feedback from the plantar flexor muscles automatically adjusts muscle activity to compensate for small ground irregularities. The delayed onset of muscle fascicle movement after dropping the platform indicates that at least the initial part of the soleus depression is more likely mediated by a decrease in force feedback than length-sensitive feedback, indicating that force feedback contributes to the locomotor activity in human walking.en_US
dc.description.peerreviewedYesen_US
dc.description.publicationstatusYesen_AU
dc.format.extent762189 bytes
dc.format.mimetypeapplication/pdf
dc.languageEnglishen_US
dc.language.isoen_AU
dc.publisherAmerican Physiological Societyen_US
dc.publisher.placeUSAen_US
dc.relation.ispartofstudentpublicationNen_AU
dc.relation.ispartofpagefrom1262en_US
dc.relation.ispartofpageto1274en_US
dc.relation.ispartofissue3en_US
dc.relation.ispartofjournalJournal of Neurophysiologyen_US
dc.relation.ispartofvolume103en_US
dc.rights.retentionYen_AU
dc.subject.fieldofresearchMotor Controlen_US
dc.subject.fieldofresearchBiomechanicsen_US
dc.subject.fieldofresearchSensory Systemsen_US
dc.subject.fieldofresearchcode110603en_US
dc.subject.fieldofresearchcode110601en_US
dc.subject.fieldofresearchcode110906en_US
dc.titleAfferent contribution to locomotor muscle activity during unconstrained overground human walking: an analysis of triceps surae muscle fasciclesen_US
dc.typeJournal articleen_US
dc.type.descriptionC1 - Peer Reviewed (HERDC)en_US
dc.type.codeC - Journal Articlesen_US
gro.rights.copyrightCopyright 2010 American Physiological Society (APS). 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.en_AU
gro.date.issued2010
gro.hasfulltextFull Text


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