Revised Design of a Passive Hydraulic Training Simulator of Biceps Spasticity

Spasticity is a common abnormal muscle behavior associated with neurological disorders and is characterized by speed-dependent increased tone in the affected muscle when induced by passive movement [1]. During the passive stretch of the muscle, additional unique clinical signs that accompany spasticity are (a) sudden increase in muscle tone at a certain joint position (catch angle), called the “catch”, (b) after the “catch”, a quick drop of muscle resistance, called the “release”, where (a) and (b) together are usually referred to as the “catch-release” behavior, and (c) limited range of motion (ROM) [1,2]. With the evolution of spasticity, these symptoms will worsen.