As the competition season approaches, it is common to see horses being exercised on the road. Many riders use roads for early fittening work because they are flat, even and convenient. Not having horses covered from head to toe in mud every time they go out is a bonus.

Horses are less likely to lose shoes on the road than in heavy soil. Boggy going also heightens the risk of soft tissue strain in horses recovering from, or with a history of, this type of injury. Another consideration is that most (but not all) horses may be more settled and easier to keep under control on a road, compared with exercising around the edge of a field or on a long, open track in the early stages of pre-season training.

Pros and cons

So what are the effects of roadwork? Time off over winter will result in some loss of bone strength. Walking and trotting on roads is ideal for stimulating an increase in bone strength, due to the vibrations induced from the road. The periods of trot required are surprisingly short, however: about five minutes per training session.

The traditional view is that roadwork is good for “hardening” tendons. Research within the past 10 years by groups at the Royal Veterinary College (RVC) and Massey University in New Zealand, to name but two, shows that this view is probably wrong.

According to studies, tendon function can be beneficially influenced by exercise, but only in young horses less than two or three years of age. Professor Roger Smith believes that while it is common practice to trot horses on hard surfaces such as roads to “firm up” their tendons, evidence from research until now has not been able to show this.

He said that, broadly, exercise helps in the development of young tendons, yet after skeletal maturity (that is, after two to three years of age) it appears to be more damaging to tendons than beneficial.

The effect of surface type is less clear, he added, but hard surfaces tend to cause greater impact forces — including possible damaging high-frequency vibrations that may have adverse effects on tendons and possibly joints.

For a horse recovering from tendon injury, the vet will usually prescribe periods of controlled exercise, as it is recognised that this is critical for tendon repair. This is a very different situation from healthy tendons that cannot be influenced positively by exercise.

Long sessions of trotting on hard surfaces pose additional risks to joints, especially in older horses or those who already have arthritic changes. As for the hoof, there is no strong evidence to suggest that roadwork is good or bad.

Vibrations could lead to damage to the laminae and other structures within the hoof. It is the hoof that plays a major role in absorbing and smoothing out vibrations, while the tendons and joints deal with the slower loading forces as the horse’s weight moves over a limb.

Hoof trauma and concussion-induced laminitis are not uncommon in endurance horses racing on hard surfaces such as compacted sand.

The presence of shoes does not change the overall or total force on the limb, which is determined by the mass of the horse and the rider. Metal shoes do cause greater concussion, however, and detrimentally alter the kinematics of the stride. They also alter how the foot interacts with the ground and how the force is distributed throughout the foot (but not higher up the leg).

A barefoot horse trotting on a road will still experience very high forces compared to trotting on grass, for example, although these will be less than for a shod horse. Just because a horse is barefoot does not mean that it is OK to do hours of roadwork at trot.

Planning sessions

Controlled roadwork can be  valuable in the early stages of bringing a horse back into work.
All that is required to increase fitness is light exercise (walk and trot), in periods
of about 30 to 60 minutes, three to four times a week, ideally spaced throughout the week and not all done over a weekend.
Walking can be daily and periods
of 60 to 90 minutes on the road are usually acceptable. I would limit trotting on the roads to five minutes per day, ideally, or a maximum of 10 minutes, for no more than three days a week. These should be evenly spaced, interspersed with two to three days’ work on a softer surface.
For a horse prone to moderate
to severe joint problems, I would consider only walking on roads.
The horse’s cardiovascular system and muscles respond quickest and best to early training. His fitness will plateau, however, if this level of training is continued beyond three weeks. At this stage it’s time to increase the work. Increasing the amount of trotting would be one way to step up training, but may not be ideal for reasons discussed.
After initial early-season roadwork, many riders switch to work on grass or all-weather gallops. Care needs to be taken, as sudden jumps in training intensity pose a big risk
of injury. Trotting on a flat road may raise a horse’s heart rate to 90 to 110 beats per minute (bpm). Trotting up
a moderately steep hill on a soft grass surface, however, could raise the heart rate of a relatively unfit horse to more than 160bpm, and cantering to as high as 190bpm.
Current research and thinking support the use of a variety of surfaces to reduce injury risk. For early training, this could mean some days walking and trotting in the arena or paddock, some lungeing in a sand school and some doing roadwork.
With any surface, consistency and evenness are key. Roadwork results in forces on the hoof about 10 times higher than on sand, woodchip and wood-fibre surfaces, and 20 times higher than working on good grass
or top-quality artificial surfaces.
A great deal of this force is absorbed by the hoof, fetlock and bones below the knee, but may still lead to joint damage. Firm, wet sand is better than roads, for those with access to beaches, but is still about eight times harder than good grass or a good arena surface.

Ref Horse & Hound; 9 February 2017