08/11/2021
Why is the walk so essential for the basic conditioning of horses?
Horses are creatures of movement. In the wild, often horses will be on the move for 10-19 hours per day browsing to sustain their forage diet. This is very different to domestic life; even with full turn out, horses often don't have access to the 100s acres of open plains available to them each day in the wild. Wild horses must roam these vast stretches of area to attain their daily intake of forage, whereas under domestication, we make this easier for them by bringing their forage to them.
The consistent movement throughout the day conditions the horse's body; which requires a certain number of cycles per day at certain strain rates, to promote the development and maintenance of various tissues. During the loading phase of the stride, when the hoof is in contact with the ground, forces are exerted on the tissues of the body which stimulates a process of conditioning and remodelling within the tissues. Without these loading patterns, tissues lose condition and strength. Muscles will atrophy and decrease in extensibility, articular cartilage has also been documented to atrophy and decrease in thickness and tendons and ligaments lose strength due to alterations in the balance of collagen synthesis and degradation.
In fact, movement has been documented to have a significant influence on the strength of bone as far back as 1892; described by Wolf’s Law “bone will adapt both architecturally and with respect to the composition to changes in mechanical loading”. Bones are living tissues and are in a constant state of remodelling (regeneration and repair) in relation to the stresses exerted from movement. As a consequence, a decrease in loading due immobilisation results in a decrease in the density and thickness of bone due to the lack of stimulus required for remodeling.
We all know that the way to get a horse fit is to make them move. The basic concept behind a fitness programme is conditioning the tissues of the body to cope with the demands of exercise, by exposing them to increasing forces and allowing this process of tissue remodelling.
Walk plays an integral role in the early stages of traditional fittening regimes for horses. Traditionally, hunters will always begin walk exercise for up to two hours per day for the first four weeks after they have been brought in from the field. After this point, from which a baseline fitness has been established, faster, discipline specific work can begin.
Walk is the gait which has the biggest influence on muscle building, which may seem counterintuitive as it is the slowest gait. However, due to the mechanics of the gait there is always one limb in contact with the ground at every point in the stride. Therefore, the body must always utilise muscular effort to carry the horse forwards, whereas at the faster gaits, such as trot, the horse can rely in part on momentum to help to carry them forwards. Other gaits will also utilise the energy saving mechanisms within the body, such as the energy recoil in the tendons of the distal limb which contribute to the forwards motion at gallop.
However, although exercise is of great importance for the health and maintenance of the tissues within the body, there are times where we must restrict exercise.
When our horses are injured, their tissues are damaged and weakened. And so the normal strain which is applied to the tissues during movement are beyond the current strength of the injured tissue. In fact, during the inflammation phase of healing (24 hours - 5 days after the initial injury) the normal tensile strength of tissues will decrease to 50%. And so, box rest and restricted exercise is often recommended to reduce forces associated with normal exercise in order to protect the tissues and allow them time to heal.
However, over time, the restriction of exercise and absence of the normal loading patterns will lead to deconditioning and weakening of the tissues. Albeit, it has been found that horses lose muscle condition at a much slower rate than humans.
Because of this, it is very important to remember that our horses are not as fit as they were pre-injury, when our horses are able to return to exercise. Not only do we have weaker tissues undergoing the stages of healing associated with the initial injury, but the horse's body as a whole has begun to decondition and is no longer as adapted to strain of exercise.
This is why rehabilitation plans begin with walk. While healing tissues are still immature in the early stages of healing, they cannot tolerate the same levels of strain as normal tissues. As the tissues mature and become stronger, they are able to withstand higher forces. This is when we can begin a controlled return to exercise, beginning with walking, because walk work provides the lowest forces of loading to the body.
At an appropriate stage of healing, rehabilitation at other gaits can begin as dictated by your veterinary professionals. Rushing the rehabilitation programme and beginning to introduce trot work too early on can have catastrophic effects on healing tissues; due to higher forces exerted on the tissues at faster gaits. At walk there are always three limbs in contact with the ground at any one time, whereas at trot this reduces to only two legs in contact with the ground and again at canter to just the one limb at times.
As a consequence, at faster gaits the horse must support their body weight on fewer limbs at certain stages of the stride, which results in increased forces being exerted on each limb at any one time. We must condition the tissues to an appropriate level of strength, so that the tissues can withstand these increased forces and avoid re-injury.
Furthermore, it is not just the healing tissues which we should think about. The horse's body as a whole will have undergone some degree of deconditioning following a period of box rest or restricted exercise. Therefore, not only is the walk work essential to promote the healing of the injured tissues but it will help to begin to recondition the horse's body globally. Much in the same way when we bring a horse back into fitness after a period of time off. Rushing this process, and skipping the walk work, will increase the risk of injury to other regions of the body, as the tissues will not have had the time to develop the same maximum tensile strength as before the period of rest.
In fact, many of my clients are familiar with the concept of building up to a baseline fitness of walking exercise when it comes to rehabilitation, before beginning any further conditioning work. My greatest successes can always be attributed to the dedication of my owners and their care for their horses.
So go and enjoy exercising your horses, and don’t forget to get your daily steps of walk in.
(This article has only scratched the surface of the benefits of walk, although further benefits can be found in our earlier article on the importance of a warm up…)
