High-speed gallop locomotion in the thoroughbred racehorse. I. The effect of incline on stride parameters.

The research examines how a horse’s galloping stride changes when moving up an incline. Measurements were taken from six horses while they gallopped at different intensities on level and incline grounds. The analysis showed that inclined galloping caused reduced limb protraction duration and increased stride frequency and hindlimb duty factor.

Methodology and Goal

• In this study, the researchers aimed to understand the effects of incline on the stride parameters of galloping Thoroughbred racehorses.
• During locomotion up an incline, power is needed to lift the body’s center of mass, which is provided by the animal’s legs during ground contact.
• The researchers employed a proven system of leg-mounted accelerometers and a global positioning system data logger to measure the horses’ foot-on and foot-off times during high-speed, over-ground locomotion.

Data Collection and Variables

• The measurements were made from six horses galloping at a speed range of 9 to 13 m/s on different sections of a track – ones that were level (0-2% incline) and others that were inclined (8-12% incline).
• Footfall timings were used to calculate variables like stance duration (the length of time foot is in contact with the ground), protraction duration (the swing phase of the stride where the hoof is in the air), stride frequency (the number of strides per second), and duty factor (the fraction of one stride in which the foot is on the ground).

Key Findings

• The results indicated that fore- and hindlimb protraction durations were significantly reduced at all speeds when galloping up an incline.
• The reduced protraction duration led to an increase in stride frequency: for instance, from 2.01 to 2.08 strides per second at 9.5 m/s and 2.10 to 2.17 strides per second at 12.5 m/s during incline galloping.
• The duty factor was found to be significantly higher for hindlimbs during incline galloping.
• With the assumed fore- to hindlimb impulse distributions, the smaller peak vertical forces in the forelimbs and increased ones in the hindlimbs were calculated when galloping on an incline.

Conclusions

• The recorded changes in the timing of strides are different from those observed in trotting horses.
• The researchers proposed that horses increase their stride frequency at a given speed to provide more power for moving their center of mass up the slope during incline galloping.