Fig. 2

Scapula assistance methods. a Therapist assistance: To dynamically stabilize the scapula, the therapist performed the modified Scapular Assistance Test (mSAT). Using the left hand as counteraction, the therapist applied an assistive force on the medial border and inferior angle of the scapula with the right hand, therefore constraining and rotating the scapula on the thoracic wall. b Scapula orthosis design: Similar to the therapist’s hand, the customized scapula interface girted the scapula’s medial border and inferior angle. A carbon plate was used to reinforce the scapula interface to allow for better force distribution. The top layer comprised a thorax harness in which a cable-based Boa-Fastening mechanism, mounted on a carbon pressure plate, was threaded. c Force model validation: With information from the force sensor and the geometry of the pressure mechanism, the applied normal force was calculated