title: Unexpected Fascicle Length Changes In Denervated Feline Soleus Muscle During Stance Phase Of Walking.
abstract: After surgical repair of traumatically severed peripheral nerves, associated muscles are paralyzed for weeks. Little is known about fascicle length changes in paralyzed muscles during locomotion. The aim of this study was to investigate to what extent, if any, muscle fascicles of denervated feline soleus (SO) change length during stance of walking when intact SO synergists are actively contracting. Hindlimb kinematics, SO fascicle and muscle-tendon unit (MTU) length, and EMG activity of SO, lateral gastrocnemius (LG) and medial gastrocnemius (MG) were measured during level and slope walking in adult cats. Measurements were taken before and 1-2 weeks following SO-LG denervation. Unexpectedly, SO fascicle lengthening and shortening during stance in all walking conditions were evident after denervation. The greatest SO fascicle shortening (17.3 ± 2.2% of a reference length) and least fascicle lengthening (1.5 ± 0.8%) after denervation were found during upslope walking, where MG EMG activity was greatest across slopes (P < 0.05) and greatest discrepancies between post denervation SO fascicle and MTU length changes occurred. These findings suggest that myofascial linkages between denervated SO and its active synergists might affect its fascicle length changes. Further studies are needed to directly test this suggestion.
authors.affiliation: School of Applied Physiology, Center for Human Movement Studies, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Ricky
authors.initials: R
authors.lastname: Mehta
authors.affiliation: Department of Human Movement Sciences, Faculty of Behaviour and Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, The Netherlands.
authors.forename: Huub
authors.initials: H
authors.lastname: Maas
authors.affiliation: School of Applied Physiology, Center for Human Movement Studies, Georgia Institute of Technology, Atlanta, GA, USA.|Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gregor
authors.affiliation: School of Applied Physiology, Center for Human Movement Studies, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Boris I
authors.initials: BI
authors.lastname: Prilutsky
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002415:Cats; D004576:Electromyography; D006614:Hindlimb / Q000294:innervation / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D010243:Paralysis / Q000503:physiopathology; D016138:Walking / Q000502:physiology*