This paper describes an Internet Of Things-based wearable system for physical rehabilitation monitoring and characterization. The system is recording movement data with 3-axial accelerometer and gyroscope sensors. Data recorded by the sensors are used for characterization of movement, thus allowing for monitoring and estimation of the patients' state at all times. Main three parts of the system are: data acquisition unit, data processing unit, and cloud-based service for remote access to data. Hardware implementation is described and shown for each of the three parts. The system is demonstrated for monitoring of elbow rehabilitation. Results show that the device can be used for highly precise and accurate monitoring of elbow flexion and extension characteristics, thus allowing for remote rehabilitation tracking through the use of the cloud-based service.