Botulinum toxin type-a effects on active and passive forces of the muscles exposed in the long-term

Botulinum toxin type A (BTX-A) is widely used for spasticity management in cerebral palsy. However, recent animal experiments indicate more involved effects of BTX-A on muscular mechanics than just weakening of the injected muscle. Acutely, BTX-A was shown to elevate passive forces and decrease length range of force exertion of the muscles exposed (via injection or diffusion into non-injected muscles). The current study assessed experimentally and showed that those unintended effects of BTX-A on muscular mechanics persist in the long-term.