The gait of pacers. 2: factors influencing pacing speed.

The research focuses on the determinants of speed in Standardbred pacers, particularly, the contribution of stride length and timing. The findings showed that despite speed changes, stance length and suspension time remained roughly the same. The crucial variables that illustrated changes in speed were suspension length and overlap time.

Methodology

• The research used Standardbred pacers and studied them at four different preset speeds.
• They analyzed selective gait kinematics, which pertains to the study of the mechanical aspects of animal movement.
• A deterministic model was proposed in which pacing speed is a function of both stride length and timing variables.

Findings

• The research found that the stance length and suspension time remained comparatively steady across the varying pacing speeds. Stance length refers to the actual distance covered by a step, while suspension time refers to the period when all four feet of the horse are off the ground.
• After analysis, the researchers discovered that the variables which differentiated the pacing speeds most accurately were suspension length and overlap time. Suspension length is the distance covered during the phase when all four feet are airborne. Overlap time pertains to the period when the two legs on the same side of a horse are in contact with the ground simultaneously.
• At near-maximum speed, pacers were able to increase their speed by extending their stride length, which was largely due to an increase in suspension length, without significant changes in suspension times.

Comparative Analysis

• The researchers compared changes in pacing speed to changes in other factors. They observed that a 22 per cent increase in pacing speed corresponds to a 13 per cent elevation in stride length, a 26 per cent increment in suspension distance, and an 8 per cent increase in stride frequency.
• Additionally, advanced placement and completion times rose by 35 per cent and 16 per cent respectively, when pacing speed increased by 22 per cent.
• Interestingly, an increase of 22 per cent in speed resulted in a 23 per cent decrease in overlap time, indicating that less time was spent with both legs on the ground as speed increased.