Comparing minimalist and comprehensive IMU-based approaches for monitoring horse rider posture

This study compares minimalist and comprehensive inertial measurement unit (IMU) configurations for monitoring rider posture in equestrian sport. The minimalist setup employed three IMUs positioned at the pelvis, sternum, and saddle, while the comprehensive configuration used 18 sensors distributed across the rider and saddle. Data collected during real riding conditions were processed in MATLAB to evaluate posture angles, symmetry measures, and center of mass (CoM) trajectories. The minimalist system achieved sub-degree accuracy for pelvis and trunk orientations, exhibited no substantial differences in key posture metrics, and required approximately 40% less setup time than the comprehensive system. However, CoM estimation showed greater variability, with an average RMS deviation of 0.185 m compared to the full-body configuration. In addition, the reduced sensor configuration demonstrated improved practicality for field deployment due to lower system complexity and reduced preparation requirements. These results indicate that minimalist IMU systems can provide accurate and field-deployable posture monitoring, while comprehensive configurations remain preferable when high-precision whole-body biomechanical measures, such as CoM estimation, are required.