We present an easy to wear and use wearable system to monitor wrist and elbow movements in musicians. The system is based on two piezoresistive sensors embedded into a garment. Pilot tests on an adult double-bass player were carried out to assess the feasibility of the device for monitoring bowing technique. Results show promising performances in identifying string changes and bow strokes. The proposed system allows for studying regularity and timing of bowing movements, thus being potentially useful in learning contexts, especially with beginner musicians.