Wireless sensor networks for rehabilitation is becoming a topic of great interest in medical applications generating a large amount of work in biomedical and communication research communities. In this line, several solutions have been proposed to provide unobtrusive, flexible and low cost systems for the supervision of rehabilitation. These solutions have focused on sensor/hardware design, platform/architecture design and signal processing algorithms. However, a little attention has been paid to network communications where there exist challenging problems specific to rehabilitation applications. In this paper, we present the design and the implementation of a new light-weight and easy to use wireless sensor network for high-fidelity rehabilitation supervision. Namely, we propose a fault-tolerant, energy-efficient communication protocol that meets the clinical equirements of rehabilitation supervision in terms of data quality and data rate. Finally, we outline the implementation of this protocol on the top of the IEEE 802.15.4 standard and evaluate its performance through intensive real world experimentations and simulations.