The traditional method of Range of Motion (ROM) rehabilitation is prone to be biased by therapists and may involve human errors. With Inertial Measurement Unit (IMU) equipped at a specific body part, an objective measurement can be obtained. In order to assess the effectiveness of the musculoskeletal fimctionalities, a measurement device, such as a goniometer, is commonly used. However, the measurement is made manually and is prone to be biased by therapists and may involve human errors.