7th IEEE International Conference Humanoid, Nanotechnology, Information Technology Communication and Control, Environment and Management (HNICEM) The Institute of Electrical and Electronics Engineers Inc. (IEEE) – Philippine Section 12-16 November 2013 Hotel Centro, Puerto Princesa, Palawan, Philippines Digital Motion Analysis System for Rehabilitation Using Wearable Sensors Denica E. Oarde Nathaniel C. Libatique Department of Electronics, Computer, and Communications Engineering (ECCE), Ateneo de Manila University Ateneo Innovation Center (AIC), Ateneo de Manila University Quezon City, Philippines denica.oarde@obf.ateneo.edu nlibatique@ateneo.edu Gregory L. Tangonan Ateneo Innovation Center (AIC), Ateneo de Manila University Quezon City, Philippines tangonan@gmail.com Dexter M. Sotto Alaize T. Pacaldo Manila Central University – College of Physical Therapy Caloocan City, Philippines bugdik_dms@yahoo.com alaize.pacaldo@gmail.com Abstract—The emergence and improvement of wearable low cost sensors gives way to an improved patient rehabilitation from impairment such as those caused by accidents or stroke. We have developed a digital motion sensing system that uses accelerometers and gyroscopes worn by the patient, and enables the rehab session to be recorded visually using a high-FPS camera. Through collaboration with interns and licensed physical therapists (PTs), we conducted tests using these wearable sensors known as the inertial measurement unit (IMU) side-by-side their norm of using a static universal goniometer (UG). An Android-based portable system was demonstrated that could be used by PTs on the move. We explored the variations of the normal range of motion (ROM) in healthy uninjured individuals, following that the functional ROM is less stringent than the conventional criteria. We can show that using the system the patient can participate in developing their digital medical records, as well as in their own wellness program Index Terms—physical therapy, wireless inertial sensors, rehabilitation, motion analysis I. INTRODUCTION Recently, wearable devices and products have been proliferating, and innovative companies such as Apple, Samsung and Google are launching their own version of these devices. From Google glass to the Apple Watch to the Polar and Garmin fitness bands, the target markets span the whole gamut from wellness to entertainment. There is a huge potential to leverage developments in wearable sensors and technologies in other areas, such as Physical Therapy (PT) practice, especially in the evaluation of progress in PT rehabilitation programs based on measurements of range of motion. Medical practitioners are very well trained in giving and analyzing data by conducting tests and through careful observation; however it is imperative to give an accurate assessment. Not only does the assessment rely on the skill of the practitioner but also on the device being used. As for physical therapists, one of the devices they use for rehabilitation is the universal goniometer. This device functions well as it should, although it cannot be helped that it introduces a number of errors that can affect the results. An example of the problem being faced by users of the UG is the introduction of human error, which may mean tester or recorder errors. Error can also be due to the lack of a standardized positioning or misalignment of the goniometer [2]. The meticulous care needed to use the UG also limits the frequency of measurements, for often, in three therapy session per week programs consisting of many repetitions and motions, only one of those three sessions are measurements recorded and logged. II. REASEARCH FRAMEWORK A. Methodology Twelve interns from Manila Central University-College of Physical Therapy, both male and female whose ages range from 18 to 24 served as subjects. Two licensed physical therapists (PTs) served as testers, and 2 nonparticipating PT