Dynamic model of the equine hindlimb during the swing phase.

The research focuses on developing a dynamic model for the hindlimb of a walking horse during the swing phase. The model aims to reflect the actual movement of a horse’s hindlimb as closely as possible.

Dynamic Model Creation

The researchers sought to create a dynamic model to simulate the swing phase of a horse’s hindlimb during normal walking motion. They did this by:

• Dividing the hindlimb into four rigid segments within the model
• Restricting the segments’ movement to the sagittal plane (the plane that divides the body into left and right halves)
• Deriving mathematical equations for the pendulum-like movements of these segments using Lagrange’s theorem, a fundamental principle used in physics to derive the equations of motion for a system

Data Collection and Application

For enhancing accuracy of the model, researchers utilized two separate utilities for data:

• Using high-speed film analysis, they calculated the morphometric (geometric) parameters of 3 horses’ hindlimbs
• Five muscle groups were selected based on their principal role in limb movement, and their activity was measured from previously obtained EMG (electromyography) data

Model Validation

In order to confirm the model’s validity, the research team compared the simulated swing movement in the model with the actual movement in live horses:

• They optimized muscle moments (the turning effect of muscle force) in the model
• Eventually, the model produced a simulated swing movement which closely mirrored that seen in the live animal, demonstrating the model’s accuracy

The model can thus serve as a valuable tool in understanding equine biomechanics, potentially leading to more effective treatments for related injuries and disorders.