Ground reaction force patterns of Dutch Warmblood horses at normal walk.

This study examines the ground reaction force patterns in Dutch Warmblood horses during a normal walk. It compares left and right fore- and hindlimb reaction forces within and between horses, finding a high level of symmetry. The researchers also found that the force patterns in the same horse were more similar over time than between different horses of the same breed.

Methodology

• The study involved recording the ground reaction force patterns of 20 clinically sound Dutch Warmblood horses (Group A) during normal walk. It used force plate tracings, a technique that measures the forces exerted by the hoof on the ground.
• The ground reaction force data from four to 10 stance phases of each limb were collected. The stance phase is when the horse’s foot is in contact with the ground.
• The collected data was then computer averaged after normalisation to the animal’s body mass and to the stance time. This process allowed for a fair comparison of data from left and right fore- and hindlimbs within and between horses, accounting for differences in size and stride duration.

Findings

• The study found that the left-to-right symmetry in the reaction force peaks of contralateral limbs of one horse exceeded 90 per cent. Contralateral limbs are pairs of legs on opposite sides of the horse’s body – that is, the left foreleg compared to the right hind leg, or the right foreleg compared to the left hind leg. A high degree of symmetry indicates that the horse is applying similar forces with both legs in a pair during a walk.
• The time in the stance phase at which the peaks occur were even more symmetrically distributed. This means that for each pair of legs, the maximum forces were exerted at the same point in the stride cycle. This finding reinforces the conclusion of highly symmetric force application.
• Force-force diagrams were created by plotting the longitudinal horizontal and the vertical ground reaction forces against each other which allowed the researchers to interpret the symmetry of loading of contralateral fore- and hindlimbs easily.

Further Exploration

• The researchers also obtained force plate tracings from another group of eight horses (Group B) over a three-year period to observe long-term trends.
• They found that the similarity of the tracings from a sound, well-trained horse over that period was better than the differences between horses of the same breed. This suggests that individual horses have consistent ground reaction force patterns over time, and that the breed does not determine these patterns as strongly as individual differences do.