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Effects of botulinum toxin type A on non‐injected bi‐articular muscle include a narrower length range of force exertion and increased passive force
Author(s) -
Ateş Filiz,
Yucesoy Can A.
Publication year - 2014
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23993
Subject(s) - isometric exercise , extensor digitorum longus muscle , exertion , botulinum toxin , anatomy , passive stretching , tibialis anterior muscle , chemistry , medicine , muscle contraction , skeletal muscle , anesthesia , range of motion , surgery
: The goal of this study was to test the hypothesis that botulinum toxin type A (BTX‐A) injection in rat tibialis anterior (TA) muscle affects the mechanics of its bi‐articular synergist, both actively and passively. Methods : Two groups of Wistar rats were tested: control (no BTX‐A) and BTX (0.1 U of BTX‐A) animals were injected exclusively to the mid‐belly of TA. Extensor digitorum longus (EDL) muscle isometric forces were measured after proximal and distal lengthening. Results : Five days after injection, BTX‐A administration changed EDL mechanics: (1) active forces decreased (proximal muscle length dependently); (2) length range of active force exertion decreased both proximally and distally; and (3) passive muscle forces increased. Conclusions : Effects of BTX‐A appear to not be limited to decreased active muscle tone, but may cause also a narrower active range of movement and increased passive resistance. Through spread of BTX‐A to a bi‐articular muscle, such effects are plausible for both joints spanned. Muscle Nerve 49 : 866–878, 2014