Epsilon Archive for Student Projects

Abstract

Equestrian sports and the interest in horses have existed for hundreds of years. It is only in the last thirty years the technological development have enabled closer studies of equine locomotion. The production of both soft- and hardware that manages to capture and analyze the fast movement of the horse has resulted in a large increase in locomotion research.
Even though the interest in horses and the different disciplines they compete in is great, there is a small understanding in how the rider influences the movement of the horse in different types of training.
There are several studies available where horses moving freely without the influence of a rider have been studied. What happens with locomotion and ground reaction forces when a rider and equipment are added is not well studied.

The objective of this study was to investigate if there are any differences in the ground reaction forces between sitting and rising trot.

The study contained seven horses. Six Grand Prix dressage horses and one dressage horse competing at intermediate level. All the horses passed a clinical examination by a veterinarian before being included in the study. The horses where ridden in both sitting and rising trot on a treadmill with their usual riders and equipment. The horses where ridden in six different head and neck positions (HNP) in several different velocities. In this study only two of the HNPs where studied.
The treadmill was instrumented with a force measuring system which made it possible to measure the vertical ground force parameters of each limb.
The force data where processed in excel for statistic evaluation.
Both impulse and the maximal force where studied, in both sitting and rising trot in the two HNPs. The impulse and the maximal force where devided with the horses weight to receive a result that could be compared between different individuals.
The difference and the quota for several different parameters where calculated. Difference and quota between rising trot on the two diagonals, between fore- and hind limbs, sitting and rising trot. The difference between observations was tested by a paired t-test. The level of significance was chosen to be p<0, 05.

The result showed that several of the horses were asymmetrical. There were a statistically significant difference in impulse and maximal force between the left and the right side of the horses in rising trot. The difference could only be seen in the fore limbs.
There were a difference between the two diagonal pairs of limbs in rising trot; there were a higher value in the limbs the rider was sitting down on. This could be seen at the impulse and at the maximal force. In one of the HNPs there was a difference in force between the two diagonals in sitting trot.

The asymmetry might be a effect of the rider because the most asymmetries between the horses left and right sides are seen in the highest HNP were the rider controls the horse most.

The most differences in impulse was also seen in the highest HNP, this is probably because an high HNP results in a shorter stance duration and a faster built up of the force.
The reason why the differences are not seen in the hind limbs is because the rider is sitting closely, almost over the fore limbs.
The diagonal the rider is sitting down on in rising trot is subject for a higher force and impulse, the difference between the diagonals are smaller when the horse is ridden in a free unrestrained position and is less influenced by the rider. This is why it is important that the rider regularly change legs in rising trot.
The differences between the diagonals in sitting trot at he high HNP shows that the rider can influence how the limbs are loaded. This mean that an increased collection sets higher demands on the rider to make sure that the horse is working symmetrically.
It seems as if an unrestrained horse has less differences between the left and right sides.