Competitive equestrian sport places extremely high loads on the musculo-skeletal system of horses. As with tendons (read article elsewhere in this edition), the formation of strong bones that can carry these loads, is of major importance.

Much research has been done in the last decade on bone formation, and the findings have been such that they have caused an almost complete turnaround in our approach to training horses.

It has long been proven that the body of a horse has to adapt to the challenges of the activity that it will participate in. These stresses differ from discipline to discipline, and a hardened show jumper will probably not withstand the stresses of endurance, and vice versa.

Speed requires bone to be of a different shape than long distance riding does, and horses must adapt to the new challenges whenever we decide to change our activity. Furthermore, time is of the essence. Adaptation cannot be rushed!

Prepare them for later

Challenges on the bones of young horses that are left on pasture (or spend much of their lives confined to small spaces) are not sufficient to prepare them for later life. Walking and trotting, with a little gallop every now and then, is great fun, but only prepares the bone structure for exactly that.

If we take a healthy young horse at the age of four and expose him to a training programme aimed at any of the many competitive equestrian disciplines, the bone has to adapt to these new challenges. If we expose him suddenly, the body responds by forming a layer of fibrous bone on top of the "normal" bone. Fibrous bone is weak and painful.

An example of this is the so-called "bucked shins" that are common in young race horses. To strengthen the bone, it is required that the lamellar (normal) bone remodels and changes its shape to be able to withstand the new stresses on a permanent basis.

Young, growing horses are programmed to adapt to new challenges on an ongoing basis. Bone remodels constantly, and reacts much quicker than it does in older horses. Young horses also heal faster when injured, something that not only applies to soft tissue wounds, but also to bone.

Bone probably becomes more brittle as the horse ages, and becomes more vulnerable to problems.

The need for speed

Studies involving race horses have shown that it is essential to include speed work at a young age to ensure that the bone develops and remodels to withstand the stresses of later life. In these studies, groups of young race horses were exposed to different training programmes.

One group was left on pasture and two groups exposed to traditional training programmes involving long, slow workouts on different surfaces. The fourth group was exposed to a programme that also included short speed bursts, three times a week, over gradually increasing distances. The pasture group showed little remodeling, while both the traditional groups developed weaker, fibrous periosteal bone.

The fourth group developed almost no fibrous bone, but showed an increase in lamellar bone. The shape of the cannon bones (the site of bucked shins) was very similar to that of four-year-old race horses that had been racing for the better part of two years. This proved that the speed work had prepared the horses for racing, while the traditional workouts had merely prepared the horses for more training.

Almost all the research done, relates to problems in racehorses. One has to be careful in applying this to other horses as well. However, the findings indicate that one should apply the same general principle to other equestrian disciplines as well.

All future performance horses have to be stressed to adapt to the activity they will participate in, and this should be done at a much earlier stage of life than previously believed. If it is speed you want, you have to expose the horse to speed at a young age.

If long distance riding is what you are aiming for, the same applies, but at the speed you intend going, at a young age. Be careful though; do not jump horses at too young an age, as little is known of the effect this might have on the joints and related structures.

If one ties this research in with the work done on tendon development, you'll find even more reason to start your horse at a young age. Tendons also adapt when still young. Exercise before two years of age has been shown to be beneficial. After that age, the tendon merely uses its inherent capabilities, without any real regeneration, and the more work done, the shorter the competitive lifespan of the horse will be.

Always keep in mind that too much is never good. Start work gradually, and do not push too hard or too far. Analyse the job you have in mind for your horse – break it down to basic elements and gradually build the stress levels to allow the bone to remodel, developing strong, lamellar bone.
The body can only adapt if we allow it to. So, beware of over-training. But that is a story for another day ...