Hindlimb net joint energies during swing phase as a function of trotting velocity.

This study investigates how speed affects the energy profiles of a horse’s hind limbs during the swing phase of a trot. The findings reveal specific patterns of energy generation and absorption at different joints which enable the horse to adjust its stride as its trotting speed increases.

Study Objective

The main goal of this research was to analyze the changes in the hind limb energy profiles of a trotting horse in relation to velocity. Previous studies had primarily focused on the forelimbs, hence the focus on the hind limbs in this study was intended to contribute to a more complete understanding of equine locomotion.

• The research involved the use of inverse dynamic analysis to calculate the net joint energies at the joints of the hind limbs in six horses trotting at varying speeds.

Findings

The researchers found that there was net energy generation at the hip and tarsus and net energy absorption at the stifle, fetlock, and coffin joints for all speeds.

• The speed-dependent bursts of energy generation at the hip moved the limb forward in early swing and started retraction in late swing.
• With the hip’s energy generation bursts, speed-dependent energy absorption occurred simultaneously across the stifle, controlling its flexion and extension during early and late swing, respectively.
• The distal limb was raised and lowered via the generation of speed-dependent energy, which flexed the tarsus in early swing and extended it in late swing.
• The energy bursts in the early swing phase increased linearly with speed, whereas in the late swing phase, they increased as a function of the square or cube of the velocity.

Significance of the Study

These findings contribute significantly to understanding the physical complexities of equine locomotion at varying speeds.

• The results are an important consideration in the context of racing and sports performance as they help in comprehending the biomechanics employed by horses to accelerate and decelerate their limbs faster as speed increases.
• The insights gained from this study can also potentially guide the design of more efficient training regimens, aid in diagnosing locomotive disorders, and help improve treatment and rehabilitation strategies for equine athletes.