Abstract: A method, system, and/or apparatus for measuring user balance with sensors of a mobile device such as a mobile phone or wearable while showing a video or animation coaching various balance exercises. A filter can be utilized to merge accelerometer and gyroscope data to reduce noise. A quaternion-based orientation pipeline can compute the device's pitch, roll, and overall orientation. The system can calculate stability scores by measuring factors such as variance or root-mean-square of pitch and roll fluctuations, acceleration magnitudes, and/or jerk/fall events. If the user experiences sudden/large movements, the system penalizes the user's score to discourage risky behavior. The user may be asked to stand in a baseline posture to measure typical involuntary arm tremor, truncal instability, or normal minimal device motion, which is used to normalize subsequent balance measurements. The system gamifies the experience by providing real-time feedback and awarding points, achievements, and an overall score.