Time domain characteristics of hoof-ground interaction at the onset of stance phase.

The research paper investigates the interaction of a horse’s hoof with the ground during the start of stance phase, with a view to understanding the forces involved that may contribute to lameness conditions in horses.

Objective

The primary objective of the study is to understand the nature of hoof-ground interaction at the initiation of a stance phase, i.e., when the foot first makes contact with the ground. The paper sets about to answer three key questions:

• Are these interactions predictable when the ground presents a constant mechanical interface?
• Is the range of directions in which collision forces act on the hoof, small or large?
• Does the initial deceleration peak post-ground contact decelerate the hoof to nearly zero velocity?

Methodology

To explore these questions, the study employs biaxial accelerometry to record the hoof acceleration during the onset of the stance phase for horses trotting on two types of surfaces — tarmac and sand. The features of the collision process are identified through vector plots as well as time-series representations of hoof acceleration, velocity, and displacement.

Results and Conclusions

The findings reveal that hoof collisions with smooth tarmac surfaces exhibited consistent and predictable patterns, similar to a spring-damper system responding to shock excitation. In contrast, collisions on sandy surfaces had more random characteristics.

• On tarmac surfaces, the initial deceleration peak did not decrease the hoof’s velocity to near zero, but on sand, it appeared to.
• The collision forces acted on the hoof in a broad range of directions on both surfaces.

Additionally, these findings hint at the presence of stiff, viscoelastic structures within the hoof that might work as shock absorbers, shielding the limb from substantial collision forces.

Implications for Future Research

The study not only deepens the understanding of hoof-ground interactions but also provides foundations for future studies. It points towards possible directions for exploring the shock-absorbing mechanism in the equine foot, considering factors such as shoe type and track surface properties on the collision forces experienced during locomotion. Such research may potentially help in identifying a link between musculoskeletal injuries, hoof function, and hoof-ground interactions.