Locomotion is the movement of bodies from one position to another. Therefore, locomotion of horse movement refers to the bodily movement of the horse in particular. The bodily movement of the horse depends on the shape, length and structure of the horse.
When galloping, a horse alternates between the front and back legs. When one side protracts, the other side retracts, hence the four legs change their position. Therefore, during a complete stride, the horse walking performs four triple stances, two diagonal and two laterals.
Starting movement with the protraction of the right hind, the left hind retracts, moving back. This position rotates the right hip a head and the left foot back. Measurement and use of some anatomic parts of the animal body has been considered objective criteria for morphological evaluation.
The horses walk is quite similar to that of human beings walk. This fact is supported by the results attained by Ronalndelli e Dust. In his study, he found out that an average hip rotation of 25, 39 degrees measuring the walk of the horse. This result is similar to that of the hip rotation observed by Van de Linden (2002) in kinematics and kinetic gait characteristics of normal children walking at a range of clinically relevant speed. Adding to this too Donald F. Hoyt* & C. Richard Taylor also feels that there is need to minimize their energy there is need to minimize their energy consumption.
Therefore, the quadrupeds need to change the gait from a walk to a trot, then to a gallon to support this. This is seen in human who change from walk to a run at a certain speed that requires less energy than running and vice versa. Therefore, they minimize the energy cost of locomotion as their speed increases. This is because the metabolic rate does increase curvilinear with change in the walking speed.
However, this is not the same to the quadrupeds as their metabolic rates increase linearly with the change in speed. In an experiment, extended gaits are taken to be tools of importance in the study of the changes of human beings. Using three trained horses, its seen that through the use of the amount of oxygen consumption as the indicator of the amount of energy consumption, the natural gait shows the s smallest amount of energy a t any speed.
According to Dr. Alan Wilson, a horse’s leg resembles a pogo stick that uses energy stored in the muscles and tendons to enable animal move forward and upwards. The stiffer the horse’s leg restricts how quickly it can transmit force to the ground and bounce back up again and increase the chances of injury. However, research has shown that fast horses can bring their legs forward quickly in preparation for the next stride. However, this is difficult and therefore slower for large and long-legged horses.
We found that the minimum, preferred and maximum sustained speeds within a trot and a gallop all change in the same rather dramatic manner with body size, differing by nine-fold between mice and horses (i.e. all three speeds scale with about the 0.2 power of body mass). Also we found out that the mass-specific energetic cost of locomotion is almost directly proportional to the stride frequency used to sustain a constant speed at all the equivalent speeds within a trot and a gallop, except for the minimum trotting speed (Heglund NC, 2002).
When in movement, the forelegs of the horse bear the weight of the horse. This leads to the occurrence of a momentary deceleration. This is followed by downward movement due to the force of gravity. That is, the head and neck moves downwards. Therefore, this leads to the stretch of the strong elastic rope found at the back of the skull. It then stretches withers hence forming the upper lining of the neck.
As the head pendulum swing s downwards, there is an effect on the spine which is rigid. This leads to the raising of the tail end part of the spine. There is also the swing of the hind legs due to elevation of the hips. This helps to keep stable the inertia that leads to the backward movement of the back legs from the stride they were before. Therefore, the expenditure of the energy used by the muscles to move them forward to in the coming stride is saved amicably.
However, the contents of the liver and abdominal are thrust against the diaphragm due to the first deceleration that occurs together with the hips elevation. This diminishes the volume of the thorax and assists respiration.
At the suspension stage when the elastic recoil of the ligament is important as it is used to take back or restore the head into original position. This happens when all the four feet are off the ground. As a result, a tug occurs which helps to draw the forelegs caused by the head being elevated. The inertia is overcome and as a result the previous backward move occurs (Chris Webster (2005)
The fore legs are then moved forward while the hind legs bear the weight. This combined performance therefore elevates the spine of the horse at a level similar to that of the withers. This leads to the flattening of the diaphragm and as a result of the liver being firmly bound to it. Hence, the thorax enlarges supporting the process of inspiration.
As the process of locomotion takes place, 100% efficiency cannot be achieved although economy is enhanced by the cyclic interchange that takes place between the many forms of mechanical energy that is available. A metabolic cost is also associated with fluctuations that occur in mechanical energy that is involved in the locomotion that is of high speed gallop type race horses (Karen E. Adolph (2000).
Therefore, natural waving of the head and neck done by the horse is termed as the head bob. Each head bob varies depending on its degree from one horse to the other. This mechanism therefore helps a galloping horse to minimize the amount of energy spent on movement or locomotion and respiration as well.
To counter the movement of the horse too the anatomy of the horse at the muscle level also matters for its movement too. Looking at the longest tendons found in the horse, that is the superficial digital flexor tendon (SDFT), disturbance of the locomotors characteristics of the SDFT takes place in most cases at the middle part of the mid-metacarpal area. However, up to date there is no evidence the morphological characteristics of collagen fibrils found at the middle and peripheral parts of the three regions that make the entire tendon. However, there is the presence of the myotendious junction (MTJ), the osteondious joint (OS) and the mid- metacarpal region (mM)
The mass average diameter (MAD) is useful since it provides important information on the mean collaged diameter and the strength of the tendon. That is the tensile strength of the tendon. This was found to be smaller in the central are as compared to that at the peripheral area of the three regions. The MAD value however was found to lowest in the two areas at the MTJ region, but increases gradually in a distal way in the OTJ which unite with the bone. Thus, the morphological characteristics suggest that it is similar to biochemical functions in some parts of the SDFT.
But for Butcher MT, the process of training and racing the lesions of the superficial tendon always are taken to be common careers ending injuries to the race horses although this is not fully understood. However, this has fatigue –resistant characteristics and force production features as well, which allow storage and return of the elastic energy by the tendons (Andrea Ellis, Julian Hill (2005).
Depending on these features and proof from history, it is therefore assumed that overloading of the SDFT is as a result of fatigue of the synergist, which is a faster contracting and deep flexor muscle. Therefore, the horse should be well taken care of and well fed to enhance its locomotion.
Karen E. Adolph (2000) Learning in the Development of Infant Locomotion, Psychology, Blackwell.ISBN0631224564.
Chris Webster (2005), The Mechanism of Motion, Performing Arts. Nohingham University press, ISBN1897676468.
Andrea Ellis, Julian Hill (2005) Nutritional Psychology pf the Horse, Medical. Elsevier, ISBN0240516664