Abstract

Objective: A novel method for assessing intersegmental angular velocities has demonstrated potential for evaluating topline movement quality in horses. However, camera-based motion capture systems restrict data collection to calibrated laboratory environments. Inertial Measurement Units (IMUs) offer a portable alternative. This study aimed to compare IMU-derived intersegmental spinal motion data with measurements obtained from a marker-based motion capture system.
Methods: Four horses were instrumented with custom marker clusters incorporating a 3D-printed base designed to secure the IMU, ensuring both systems recorded data from the same anatomical location and orientation. A total of 3,737 paired time points across 37 gait cycles were analyzed. Agreement in intersegmental angular velocities across three planes of motion was evaluated using Bland–Altman analysis and Intraclass Correlation Coefficients (ICCs).
Results: Bland–Altman analysis demonstrated no significant systematic bias between methods. ICCs indicated excellent agreement in 7 of 9 comparisons (r = 0.964–0.991) and good agreement in the remaining 2 comparisons (r = 0.854 and 0.875).
Conclusions: IMUs provide a valid alternative to marker-based motion capture systems for measuring intersegmental angular velocities in horses.
Clinical Relevance: Strong agreement between IMU and motion capture data supports the use of IMUs for assessing topline function in non-laboratory, clinically relevant settings.