Development of a Bowden-cable-based Exoskeleton Suit for Assisting Passive Stretching Exercises in Patients with Frozen Shoulder

Abstract

This paper presents the design of a Bowden-cable-based exoskeleton suit specifically developed for assisting with passive stretching exercises for patients with frozen shoulders. Passive stretching exercises are essential in the treatment of frozen shoulders, as they require a higher intensity than what patients can achieve through self-stretching alone. Consequently, the assistance of a therapistis necessary. However, current suits designed for this purpose have drawbacks. Some are too bulky, making it difficult for therapists to interact with patients, while others are too compact to adequately support passive stretching exercises. With this in mind, the objective of this paper is to explore the requirements that a suit must meet to effectively assist patients with frozen shoulder during passive stretching exercises. Based on our findings, we propose an exoskeleton suit that is easy to wear, utilizes a Bowden cable for reduced size, and incorporates a ratchet mechanism to support therapists in the most fatiguing movements, such as forward flexion and abduction. Furthermore, we conducted wearability and functional evaluations to validate the fabricated exoskeleton suit. The results confirmed that the proposed suit is comfortable to wear and effectively assists both the wearer and the therapist in performing forward flexion and abduction movements during stretching exercises.