The number of people in need of rehabilitation of the musculoskeletal system is increasing. To maintain the best therapy outcome without extending the demand for physiotherapists, it is necessary to enable patients to perform the rehabilitation exercises at home. A biofeedback training system ensuring accuracy of the movement performed is currently developed. It will be adaptable to the individual needs of the patient. Different sensors and training programms have been evaluated in small clinical trials to evaluate the biofeedback system with respect to accuracy and reproducibility of the exercises performed.
The evaluation procedure for verifying the effects of the training system is based on video-based three-dimensional movement analysis of upper extremities. The calculation of joint angles is based on the rigid body model introduced by Schmidt in 1999. This model uses rigid segments for the head, trunk, upper arm, forearm and hand connected by ideal ball socket joints to determine movement in all anatomical joint axes of the upper extremities. These are wrist, elbow, shoulder and sternoclavicular joints. Based on this approach, a collective of healthy patients was observed while performing exercises of upper extremity rehabilitation with and without the training system. The reproducibility of the performed movement with respect to the manner of performance, range of motion, velocity and effort has been compared.
Preliminary results show that there is a significant increase in reproducibility with respect to range of motion and velocity of the performed movement when using the training system. Fig. 2 shows the rotation angle of the shoulder with and without feedback which ensures an optimal movement of the joint.
A high degree of reproducibility is an indispensable precondition for the implementation of an individual autonomous training in home environment. The biofeedback system for training at home offers a high quality for exercise performence.