Joint moments and power in equine gait: a preliminary study.

This research article discusses a method to estimate joint moments of force and power in horse’s forelimbs during gait using video and force platform data. Essentially, the study focuses on understanding the energy absorption and generation in various joints of horse’s forelimbs during different phases of a stance.

Research Method

• The researchers used a special high-speed video system coupled with force platform data to record the movement of a horse’s forelimb during gait.
• The study was conducted on a healthy Dutch Warmblood horse for which five walking trials were conducted.
• Through the recorded data, researchers were able to measure the positional and angular data in the sagittal (vertical) plane, which were then combined with vertical and cranio-caudal ground reaction forces (forces exerted by the ground on the horse’s limbs) to calculate net joint moments of force.

Analyzing Joint Forces and Power

• The study specifically analyzed the moments of force in the sagittal plane across the carpal (wrist equivalent), fetlock (ankle equivalent) and coffin (similar to human fingertips) joints during the stance phase of the forelimb.
• The mechanical power was calculated by multiplying the net joint moment (the rotational equivalent of linear force) with the joint’s angular velocity (how fast a joint angle is changing).

Findings on Joint Energy Absorption and Generation

• The study elaborated energy absorption and generation patterns across different joints in the horse’s forelimbs. Each joint displayed varying moments of energy generation and absorption, depending largely on whether the joint was flexing or extending and whether the joint was in the early, mid, or terminal phase of the stance.
• For instance, the carpus absorbed energy in the early stance phase against a flexor moment (force causing joint flexion) and then absorbed energy at the end of the stance as the carpus flexed against an extensor moment (force causing joint extension).
• The fetlock showed patterns of energy absorption in the early stance followed by alternating periods of positive and negative work in mid-stance. The fetlock generated energy as it extended for the push-off phase.
• The coffin joint mostly showed an extensor moment throughout the stance. First, it absorbed energy followed by a longer phase of generation. During the terminal stance, a flexor moment was produced, which was accompanied by a period of energy generation for the push-off.