How the horse moves: 2. Significance of graphical representations of equine hind limb kinematics.

This research studied how horses move, specifically focusing on the function of the hind limbs during locomotion. By capturing the motion of trotting horses on a high-speed treadmill, the research provides a graphical representation of hind limb kinematics, enhancing our understanding of how different juoints work together during horse movements.

Methodology and Data Collection

• The study involved 24 two-year-old Dutch Warmblood horses trotting at a speed of 4 m/s on a high-speed treadmill.
• The horses’ movements were recorded using kinematic analysis equipment. This data was then graphically represented using joint angle-time, angle-angle, stick and marker diagrams.
• To standardize the data, joint motions were referenced to the angles observed when the horse was standing squarely. The motion data was also time-standardized to align with the duration of the stride cycle.

Understanding Equine Hind Limb Function

• By standardizing and averaging the data, the researchers were able to calculate mean joint curves, which provide insight into the function of the different segments of the equine hind limb.
• The movement of the hind limb in the sagittal plane (from front to back) appeared to swing around a central pivot point in the acetabulum (a part of the horse’s hip joint).
• During the stance phase (when the horse’s foot is on the ground), there were observed extensions of the fetlock joint (the ‘ankle’ of the horse) and stance flexions of the stifle (knee), tarsal (hock) and coffin joints. These movements are indicative of the horse’s hind limb absorbing shock.
• In the swing phase (when the horse’s leg swings forward), a mechanism called the reciprocal apparatus links the stifle and tarsal joint motions, and also has an impact on the fetlock joint. This linkage was evidenced by synchronous flexion (bending) and extension (straightening) across these three joints.

Implications and Applications

• Graphically presenting the hind limb motion helps to demonstrate the relationship between kinematics (the study of movement) and function. This analysis contributes to our understanding of horse movement.
• The findings from this research can be applied in clinical studies, particularly for quantifying equine hind limb coordination in the sagittal plane. These graphical representations and measurements can prove valuable in diagnosing and treating different pathological conditions affecting horses’ limbs.