Development of an inertial motion capture system for kinematic analysis of ski jumping

In this research, a fully automatic inertial motion capture system for the determination and analysis of kinematic motion parameters in ski jumping was developed. Two databases were created for the implementation of the measurement system: one basic database acquired in a laboratory setting and one database acquired during a summer ski jump season on an actual ski jumping slope. First, the former database was used to set up the fundamental data processing method. Next, this method was extended to derive jump kinematics for motion analysis in the larger summer jumping data set. Data analysis showed that the determined body kinematics varied largely in heading angle due to variances in the magnetic field near the top of the ski jumping hill. Therefore, a novel method for the additional compensation of magnetic disturbances was added to the processing framework. The resulting system output data indicated that the final body orientations, joint positions and joint angles were of good and meaningful accuracy. The enhanced inertial capture system consequently constitutes a reliable and very accurate tool to evaluate ski jumps from inertial sensor data under high data comparability and repeatability within different athletes and capture sessions.