Journal of Bionic Engineering (2025) 22:1085–1095https://doi.org/10.1007/s42235-025-00669-w

A Mechatronic Device for a Standardized Execution of the Muscle Shortening Maneuver

Saad Jamshed Abbasi1  · Simone Rossi1  · Paolo Lippi2  · Piero Maria Orsini2  · Riccardo Bracci2  · Manuel G. Catalano3  · Matteo Bianchi1,2

1 Department of Information Engineering (DII), University of Pisa, 56127 Pisa, Italy 

2 Centro Piaggio, University of Pisa, 56127 Pisa, Italy 

3 Soft Robotics For Human Cooperation and Rehabilitation, Italian Institute of Technology, 16163 Genoa, Italy

Abstract 

Muscle Shortening Maneuver (MSM) is a rehabilitation technique successfully applied to several pathological conditions. The concept is to passively elongate and shorten the target muscle group of the affected limb. As a result, the functionality (muscle strength and range of motion) of that limb is improved. The existing system induces these oscillations manually or without any feedback control, which can compromise the effectiveness and standardization of MSM. In this paper, we present a mechatronic system that can precisely deliver motion oscillations to the upper limb for a controllable execution of MSM. First, we collected the parameters (frequency and amplitude of the oscillations) from a system where a motor was heuristically used by a well-experienced therapist to induce the oscillations (without any feedback control). Based on these specifications, we chose the motor and rebuilt the experimental setup, implementing a sliding mode control with a sliding perturbation observer. With our system, the operator can choose a given frequency and amplitude of the oscillations within the range we experimentally observed. We tested our system with ten participants of different anthropometry. We found that our system can accurately reproduce oscillations in the frequency range 0.8 to 1.2 Hz and amplitude range 2 to 6 cm, with a maximum percentage normalized root mean square error around 7%. 

Keywords Rehabilitation · Muscle shortening maneuver · Upper limb · Mechatronic device · Control · Trajectory tracking