Abstract
To make the diagnosis of equine lameness and to make clear the cause of disorders of the locomotor system, the floor reaction of the ground on the hoof was measured in normal walking and trotting horses. The measuring components used were three force component (Fx, Fy and Fz), coordinates ax and ay at the point of force application, a torque moment about Z-axis (M'z) and two dimensional analyses of floor reaction force (α, β, γ-diagram). A vertical component with a pattern of two peaks was obtained from both fore and hind in walking horses. Its peak values were 56.2% and 68.0% of body weight in the fore leg and 48.6% and 42.9% of body weight in the hind leg. Small peaks were obtained in front of the first peak and after the second peak of the vertical component. The positive and negative force values of a horizontal component were the same as those in walking horses. In trotting horses, the vertical component showed a pattern with only one peak in both fore and hind legs. The peak value of the vertical component was 105% of body weight in the fore leg and 92.8% of body weight in the hind leg. There was an increase in the positive value of the fore leg and the negative value of the hind leg in the horizontal component. These results suggest that the fore leg may provide the function of support and the hind leg the function of propulsion. The lateral component showed a different pattern in every horse. The pattern of floor reaction force faithfully demonstrated the action of walking and trotting in a horse.
