Determining Objective Parameters to Assess Gait Quality in Franches-Montagnes Horses for Ground Coverage and Over-Tracking – Part 1: At Walk.

This study examines the movement characteristics of Franches-Montagnes stallions by using 3D motion capture and inertial measurement units. The collected data establishes clear measures to assess gait quality traits, specifically ground coverage and over-tracking, at the walk.

Research Purpose and Methodology

• The research aimed to understand the complex movement patterns of ground coverage and over-tracking in Franches-Montagnes horses. Ground coverage refers to the forward movement of the horse’s front and hind limbs in relation to stride length, whereas over-tracking describes the degree to which the hind foot lands ahead of the place where the corresponding front foot landed.
• This investigation involved measurement of limb and body kinematics of 24 Franches-Montagnes stallions. The data was collected using a 3D optical motion capture system installed on a treadmill as the horses performed an incremental speed test within the walk range of 1.4-2.0 m/s.
• Through linear mixed-effect models, the researchers estimated the significance and amount of the variance of kinematic parameters on stride length and over-tracking distance, taking into account speed and horse as random effects.

Analytical Models and Results

• Two separate models were tested, a full one which utilized all the parameters that could be measured by the 3D optical motion capture (OMC), and a reduced model that used a subset of parameters also measurable with inertial measurement units (IMUs).
• The maximum forelimb retraction angle parameter had the highest impact on stride length variance (11%) when measured with OMC, and the range of pelvis pitch (10%) when measured with IMUs.
• The range of pelvis pitch also proved relevant for quantifying over-tracking distance, accounting for between 24% to 33% of its variance.
• The kinematic parameters were then correlated with subjective scores from six breeding experts to check the external validity of the data. This correlation revealed that most breeding experts’ scores were significantly associated with the fore and hind limb protraction angles.

Study Conclusion

• The research concluded that both ground coverage and over-tracking can be objectively quantified using either 3D optical motion capture or inertial measurement units.
• These findings contribute to the understanding of equine locomotion and can provide a scientific basis for the objective assessment of gait quality in horses.