Inertial measurement system for swimming rehabilitation

The occurrence of light spinal diseases due to the low physical activity of daily life is continuously increasing. Recovering form these diseases requires specific and directed physical activity and can conveniently performed in swimming pools where the apparent weight reduction due to the water helps letting patients perform the relief movements. Unfortunately a way for easily assessing the correctness of the patient's movement is still missing and in most cases everything relies on the capabilities of the trainers, which must be continuously present. This paper describes an attempt to arrange a simple system suitable for a quasi on-line self assessing to the movement correctness. The proposed system is based on two inertial assemblies to be worn on the wrists and capable of sending data to a receiver installed at pool border. Data received from these small assemblies are processed to show the patients the symmetry of their movements, which is connected to the movement efficiency. The inertial assemblies are arranged by using a commercial miniaturized Inertial Measurement Unit, a Teensyduino board, and a μPanel WiFi transmitter which is able to send the data to the received during the swimming. The receiver process the data in-line so that, when the patients stop swimming to take a rest, they can be displayed to the patients as a self-assess of the just performed activity.