Natural asymmetry in horses can be a major cause of physical pain, discomfort, or even lameness. As a result, it can affect a horse’s balance, movement and responses, which will then influence behaviour and emotional reactivity.

Symptoms of Natural Asymmetry in Horses

Symptoms include:

• Difficulty turning on one rein
• Uneven contact or balance
• Saddle slipping
• Difficulty with canter leads
• Tension, rushing, tripping or bucking

If you are experiencing some of these challenges, learning to recognise and correct natural asymmetry in your horse will make a huge difference.

Why Natural Asymmetry Is Not necessarily a Problem

This imbalance is not a problem for the horse in nature. In fact, having a dominant front leg and pushing back legs is very helpful when you need to move fast to get out of the way of predators.

Can Natural Asymmetry Be Improved?

However, when we add the weight of a rider, the horse’s natural asymmetry gets exagerated, and the symptoms start to become a problem for the horse.

Natural asymmetry is normal, but it still needs to be understood, particularly when we ask the horse to carry a rider.

The Balance First exercises can help by improving the horse’s balance, coordination and ability to carry weight evenly. Used consistently, they will develop the horse symmetrically by helping him find balance, suppleness, straightness and self-carriage, reducing the effects of natural asymmetry.

Persistent lameness, pain or sudden behavioural change should always be investigated by a qualified veterinary professional.

Ultimately, the first step is to learn to recognise your horse’s natural asymmetry and to understand how asymmetry in horses affects movement.

What Research Tells Us About Natural Asymmetry in Horses

Research into equine laterality suggests that most horses show natural sidedness, just as humans do. Studies have shown that these preferences can influence movement and the way horses use their bodies under saddle.

Understanding this natural asymmetry gives us a starting point for helping the horse become more balanced and comfortable in work. This research article into equine movement from Frontiers in Veterinary Science explains the science in more detail: Research into equine laterality and movement.

Types of Natural Asymmetry

The front legs, with their fragile bones, are not designed for taking the weight of a rider. By contrast, the back legs are much stronger with big muscles, heavy bones and joints that act like springs. This difference is important when we consider natural asymmetry.

Front leg dominance

Just like humans, horses are right or left-handed in their front legs.

The dominant front leg tends to be stronger and better coordinated. Therefore, if he is not taught to move in balance, the horse will tend to put more weight on the dominant leg.

Because the front legs are relatively straight and fragile, this can cause problems like navicular disease or sprain injuries.

You can get an idea of whether your horse is right or left-handed in front by noticing which leg he usually chooses to put the most weight on when at rest. In addition, observe him in different situations so you can identify a consistent preference.

When he is in the field grazing, his preferred leg will probably be the leg that he places forwards the most frequently. This can therefore provide another useful clue.

Another good test is:

1. Place some food about 5 metres (15 feet) in front of your horse.
2. Encourage your horse to come forward to eat the food.
3. When your horse begins to eat the food, note whether the left or right hoof is placed furthest forward.
4. Do this 5 more times.

Your result:

1. If your horse places the left foot forward most of the time, he is likely to be left-handed.
2. If your horse places the right foot forward most of the time, he is likely to be right-handed.
3. If the outcome is 50-50, it could be that your horse has no preference and is ambidextrous.

Back leg dominance 

Horses are also left or right-handed in the hind legs. They tend to have one pushing hind leg and one carrying hind leg. In other words, each leg has a different role in helping the horse move and support his weight.

Did you ride a scooter as a child? Without thinking about it, most people put the same foot on the scooter every time, and that’s their carrying leg. They use the other leg to push backwards against the ground to make the scooter move forward. That is their pushing leg.

The principle is the same for the horse:

• A carrying hind leg bends easily like a spring, steps under the horse’s ribcage and carries weight.
• A pushing hind leg is weaker and straighter and pushes backwards.

Lateral bending

The spine can bend to the left or to the right from the head to the tail. From birth, almost all horses either bend more easily to the left or to the right, in other words a horse can be left-bent or right-bent.

Some of the symptoms of a left-bent horse

• The horse’s back muscles on the left will be stronger but shorter and stiffer than on the right.
• The horse’s back muscles on the right will be weaker but more supple, and will stretch more easily than on the left.
• The saddle tends to slip to the right because the muscles are weaker on that side.
• The stirrup on the right tends to hang lower.
• On the left rein a left-bent horse will:
  • Turn easily.
  • Look to the inside.
  • Over-bend to the left.
  • Fall out through the outside shoulder.
  • Want to make the circle bigger.
• On the right rein a left-bent horse will:
  • Find it more difficult to turn.
  • Take the wrong lateral bending.
  • Look to the outside.
  • Fall in on the inside shoulder.
  • Want to make the circle smaller.

For right-bent horses, it is the opposite. However, the same relationship between bending and front-leg preference still applies.

Diagonal imbalance

Natural asymmetry in horses can affect movement in several connected ways. Left-bent horses tend to be right-handed in front with a pushing left hind leg. Right-bent horses tend to be left-handed in front with a pushing right hind leg. This creates a diagonal imbalance, where the centre of mass is pushed diagonally across the horse from the pushing hindleg towards the dominant front leg.

Vertical imbalance

When a horse is asked to move on a circle, for example as in longeing, if the horse’s diagonal imbalance has not been addressed, because of the centrifugal force he will tend to lean in vertically to stop himself falling over, like a motor cyclist riding a steep turn. He will then start to go faster and faster in order to stay upright, and this can cause the horse to panic because he is so out of balance, and go into flight. We often see this when horses take off on the longe. To address this we teach the horse to turn on the circle in both directions.

Topline imbalance

The diagonal and vertical imbalance culminates to cause topline imbalance, where the muscles of the topline shorten, the under neck muscles engage, the horse’s head and tail are raised, the back dips down, the hind legs push backwards, the centre of mass is towards the shoulders, and the abdominals are not engaged.

Case study

Left-bent, right-handed horse

When I started training Moon, he was very stiff in his body because he was strongly right-handed and left-bent.

This meant that when I asked him to lower his head and neck forward down and bend to the right, it was very difficult for him.

A circle to the right was much more difficult than to the left because he wanted to fall on his right shoulder. As a result, the exercise exposed the effect of his natural asymmetry.

He would rush and fall forward, getting faster and faster, and he would trip often. Consequently, his movement became increasingly difficult to control.

When I was able to control his centre of mass and move it back and away from his right shoulder, he was able to bend on the circle and carry himself in balance. Therefore, his movement became more comfortable and coordinated.

The following images show how Moon’s balance and posture changed as he learned to organise his body more effectively.

In conclusion

Addressing the physical natural asymmetry in your horse is vital. However, it is also important to work on the mental, emotional and spiritual areas of imbalance.

Very often, correcting the physical imbalance will help with the mental and emotional areas, but it can also work the other way around. For this reason, looking at the whole horse is important when addressing natural asymmetry.

With this in mind, we must therefore provide a tailor-made solution for every horse.