A highly automated, wireless inertial measurement unit based system for monitoring gym-based push-start training sessions by bob-skeleton athletes

Abstract

Wireless Inertial Measurement Units (WIMUs) are increasingly used to improve our understanding of complex human motion scenarios. In sports this allows for more valid coaching, selection and training methods leading to improved athletic performance. The Push-Start in the Winter Olympic sport of Bob-Skeleton is poorly understood but believed to be critical to performance. At the University of Bath a piece of gym-based equipment called the “Assassin” used by athletes to practice the Push-Start was instrumented with a custom WIMU system to investigate this motion regime. A test subject performed 36 runs, comprising 3 runs at each of 12 combinations of 3 Incline and 4 Weight settings. A developed algorithm automatically identified valid data-files, extracted the Pushing-Phase Acceleration data, and estimated sled Velocity and Displacement. The average velocities derived from an existing Light-Gate and WIMU data-files were comparable, with an average Root Mean Squared Error of 0.105 meters per second over the 52 valid WIMU data-files identified, covering 11 of the 12 Weight and Incline settings. Additional investigation of WIMU data revealed information such as: step count; track incline; and whether weights had been added could be determined, although further verification and validation of these features are required. Such an automated WIMU-based system could replace performance monitoring methods such as Light-Gates, providing higher fidelity performance data, additional information on equipment setup with lower-cost and greater ease-of-use by coaches or athletes. Its portable and modular nature also allow use with other training scenarios or equipment, such as using additional on-body WIMUs, or use with outdoor and ice-track sleds, enabling performance monitoring from the gym to the ice-track for improved candidate selection, comparison and training in Bob-Skeleton and other ice-track based sled sports.