Effects of botulinum toxin type A on non-injected bi-articular muscle include a narrower length range of force exertion and increased passive force

Filiz Ateş, Can A. Yucesoy

Research output: Contribution to journalArticle

11 Citations (Scopus)


Introduction: 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.

Original languageEnglish
Pages (from-to)866-878
Number of pages13
JournalMuscle and Nerve
Issue number6
Publication statusPublished - 2014
Externally publishedYes



  • Bi-articular muscle
  • Botulinum toxin type A
  • Muscle force length
  • Passive force
  • Range of force exertion
  • Rat extensor digitorum longus muscle
  • Spread of BTX-A

ASJC Scopus subject areas

  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)
  • Physiology

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