This study proposes a method for range-of-motion (ROM) estimation based on the acceleration and geomagnetic data acquired using a single miniaturized wireless sensor node. An experiment on eight shoulder rehabilitation protocols in real human subjects has been conducted, with a sensor placed on user's left and right upper arms and wrists. The experimental results demonstrate the limitations of estimation methods that use sensors placed on skin surface and that, despite being a different body segment, the wrist is a better placement position for sensor-based shoulder joint ROM measurement than the shoulder itself.