Current sports-medicine practices for understanding the motion of athletes while engaged in their sport of choice are limited to camera-based marker tracking systems that generally lack the fidelity and sampling rates necessary to make medically usable measurements; they also typically require a structured, stable "studio" environment, and need considerable time to set up and calibrate. The data from our system provides the ability to understand the forces and torques that an athlete's joints and body segments undergo during activity. It also allows for precise biomechanical modeling of an athlete's motion. The application of sensor fusion techniques is essential for optimal extraction of kinetic and kinematic information. Also, it provides an alternative measurement method that can be used in out-of-lab scenarios.