An illustration of the interactive balance training program. A: The ankle reaching task involves moving a red dot from a start circle (yellow) to a target circle (green) in a straight line. B: The ankle reaching task is conducted in anterior-posterior and medial-lateral direction. C: The trajectory of the cursor is rotated by an angle of 20°. The participant needs to observe this change in trajectory during the reaching task and compensate by adjusting ankle/hip coordination. D: The participant is challenged to cross virtual obstacles appearing on the screen. Lower extremity feedback is provided by wearable sensors.