Effects of botulinum toxin type A on non‐injected bi‐articular muscle include a narrower length range of force exertion and increased passive force. Issue 6 (June 2014)

• Record Type: Journal Article
• Authors: Ateş, Filiz; Yucesoy, Can A.
• Is Part Of: Muscle & nerve. Volume 49:Issue 6(2014:Jun.)
• Page Start: 866
• Page End: 878
• Publication Date: 2014-06
• Subjects: Neuromuscular diseases -- Periodicals; Muscles -- Periodicals; Nerves -- Periodicals; 616.74
• DOI: 10.1002/mus.23993
• Languages: English
• ISSNs: 0148-639X

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p> <italic>Introduction</italic>: 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. <italic>Methods</italic>: 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. <italic>Results</italic>: 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. <italic>Conclusions</italic>: 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. <italic>Muscle Nerve</italic><bold>49</bold>: 866–878, 2014</p> </abstract>