Validation of distal limb mounted inertial measurement unit sensors for stride detection in Warmblood horses at walk and trot
F. M. Bragança, S. Bosch, J. P. Voskamp, M. Marin-Perianu, B. J. Van Der Zwaag, J. C. M. Vernooij, P.R. van Weeren and W. Back (2016), Equine Veterinary Journal ISSN 2042-3306, DOI: 10.1111/evj.12651
Inertial measurement unit (IMU) sensor‐based techniques are becoming more popular in horses as a tool for objective locomotor assessment. The objectives are to describe, evaluate and validate a method of stride detection and quantification at walk and trot using distal limb mounted IMU sensors. A total of seven Warmblood horses equipped with metacarpal/metatarsal IMU sensors and reflective markers for motion capture were hand walked and trotted over a force plate. Using four custom built algorithms hoof‐on/hoof‐off timing over the force plate were calculated for each trial from the IMU data. Accuracy of the computed parameters was calculated as the mean difference in milliseconds between the IMU or motion capture generated data and the data from the force plate, precision as the s.d. of these differences and percentage of error with accuracy of the calculated parameter as a percentage of the force plate stance duration. Accuracy, precision and percentage of error of the best performing IMU algorithm for stance duration at walk were 28.5, 31.6 ms and 3.7% for the forelimbs and −5.5, 20.1 ms and −0.8% for the hindlimbs, respectively. At trot the best performing algorithm achieved accuracy, precision and percentage of error of −27.6/8.8 ms/−8.4% for the forelimbs and 6.3/33.5 ms/9.1% for the hindlimbs.