Accuracy and precision of gait events derived from motion capture in horses during walk and trot.

The research article investigates the accuracy and precision of determining gait events in horses through various motion detection algorithms, highlighting the need for different methods for front and hind limbs.

Objective and Methods

• The main purpose of this study is to verify the accuracy and precision of stance-phase timing detection in the gait of horses, using motion capture technology. Five previously published algorithms for detecting hoof-on and hoof-off events (the instances when the hoof touches and leave the ground, respectively) were examined against a reference standard, provided by eight force plates.
• The participants for this study were six horses, which were made to walk and trot over the force plates while twelve infrared motion capture cameras synchronously recorded their movements.
• The five algorithms tested were based on various combinations or metrics related to hoof velocity, the fetlock angle (the joint that connects the horse’s foot with its leg), displacement relative to the horse’s centre of mass, and vertical acceleration of the hoof.

Findings

• Total of 480 stance phases (240 in walk and 240 in trot) were assessed to determine the effectiveness of the algorithms.
• Method D (based on horizontal velocity of the hoof relative to the Centre of Mass) provided the most accurate and precise measurements of stance phase duration during walk, showing 4.1% bias for front limbs and 4.8% for hind limbs. This indicates that method D can predict stance phase duration relatively accurately in walking horses.
• For the trotting phase, a combination of methods was found to be the most effective. Method A (based on the horizontal velocity of the hoof) was best for detecting the hoof-on event and method E (based on the vertical acceleration of the hoof) for the hoof-off event in the front limbs, resulting in a -6.2% bias of stance phase duration. Meanwhile, method B (based on Fetlock angle and horizontal hoof velocity) showed a bias of 3.8% of stance phase duration for the hind limbs.

Conclusion

• The research concludes that motion capture can accurately and precisely detect gait events in walking and trotting horses. However, the study’s findings underline the necessity for alternate algorithms when interpreting gait data from the front and hind limbs of trotting horses.