The fella in this picture is riding an eight year old Dutch warmblood/thoroughbred cross, whom he has owned for six years. They do unaffiliated dressage, and a more skilful rider occasionally competes the horse at a higher level.

The picture provides us with an interesting anatomy lesson. If you look at the horse’s neck, you can see a very clear line of muscle. It is the brachiocephalic, which attaches into the skull (as the brachiocephalic tendon, forming the top few inches of the line that you can see) and passes beneath the crest, turning downwards towards the bottom half of the shoulder blade. We then loose sight of it, but it inserts into the humerous (the bone which lies between the shoulder blade and the elbow) a little below and behind the point of the horse’s shoulder. It assists in lifting the shoulder and foreleg, and in this horse it bulges as strikingly as I have ever seen.

Whilst this muscle is over-developed, the horse looks wasted in the triangle which lies above it and in front of his shoulder blade. This triangular shape should be filled out by the cervical part of the trapesius muscle, and should appear more developed than the top of the neck. If you were to ride this horse, you would look down on his neck from above and see that his neck is much wider towards the poll than it is at its base. (Try this on your own horse, and observe the shape that you see.) Given that the head is essentially a weight on the end of a long pole, it follows that the horse whose neck is wedge-shaped (wider at the base than is it at the poll) has a much more efficient muscle system for counter-balancing the weight of his head. Unfortunately, very few horses are well enough ridden to have wedge-shaped necks.

A strong topline is built when the neck stretches down so that the crest lies close to horizontal. Gravity then acts on it, and in good work, the extensor muscles along the top of the neck help the horse to defy that pull and hold his neck in place. They make an isometric contraction, in which the length of the muscle stays the same but its muscle tone increases considerably. If you were to lean forward in your chair, your back muscles would contract in the same way to stop you from falling over. This muscle use is extremely tiring and it builds muscle bulk very quickly. In the horse, it creates the line of a well-developed crest.

When the top of the horse’s neck shortens and his ears come back towards the rider’s chin, the extensor muscles work in a different way, contracting isotonically. In this kind of muscle use, the two ends of the muscle become closer together; but as the muscle shortens the tension in it stays more or less the same. This is a less strong form of muscle contraction. It is much less tiring than the isometric contraction through which those same muscles hold the horse’s neck in the ‘on the bit’ position, and it does not build so much muscle bulk.

In the hollow backed horse, both the muscles along the top of the neck and the mucles along the back are in an isotonic contraction. As they become shorter his belly muscles become longer, making his stomach sag. This mechanism is often compared to an unstrung bow, with the back muscles as the wood and the belly muscles as the string. In contrast, the back and belly muscles of the horse who works correctly function like a strung bow, and as the back lifts and rounds, the string (or belly muscles) shortens. If you have last month’s article to hand, compare the shape of that horse’s belly with the shape of this horse’s belly. Fitness is unlikely to be the issue here; it is the use of the back and belly muscles which makes the difference to their shape.

It is, however, difficult to get the belly muscles of the horse to shorten when they are pathologically weak. This horse, I fear, has not ‘cottoned to’ the fact that these muscles can support his back and his guts, and changing this is probably the key to changing the whole horse. But it will require very skilful riding, and it might help to do belly lifts with him when grooming and before you mount. Place your finger tips along the midline of his stomach just behind the girth, then wiggle them and dig them into him. But begin gently, using half an eye to observe how his back rises, and keeping the rest of your eyes on his hind leg!

When the horse is correctly ‘on the bit,’ the topside of the neck is in an isometric contraction, and underside of the neck is in an isotonic contraction, through which the muscles shorten to bring his nose closer to his chest. This is the weaker kind of contraction that does not develop much muscle. The excessive muscle development that you see in the photograph, is, I think, indicative of a horse who uses the braciocephalic muscle to hold his head up and in. The equivilent muscle in your body is the sternomastoid, which runs from below and behind your ear down the front of your neck towards the indentation in the centre of your collar bone. Tuck your chin in, pull it backwards, and feel (with your hand) how the muscle bulks out on each side. It is not very comfortable to maintain this position for long.

. As a result of his muscle use, this horse will have little freedom of movement in the shoulder, and will pull himself along with his forelegs rather than pushing himself along with his hindlegs. It is a rather disturbing state of affairs – although to an undeducated eye the horse may not look desperately wrong. The burning question is, ‘What is his rider to do?’

The line up of his body is reasonable, although he is a little back with his shoulders and forward with his foot. He is doing a fairly good job in supporting his own body weight (although I fear that he is a little heavy for this horse). The position of his hands arouses suspicion in me, and I wondour what would happen if he advanced and lifted them. I also wondour how strong his contact is. Since we are only seeing this rider in walk, we cannot know how well he copes in the faster gaits; but I suspect that his body control is not all that it could be.

The answer to his problem will lie – as it almost always does – in accessing his muscles in an isometric way. This will enable him to stabilise his body and stay ‘with’ the horse as the movement of the hind leg kicks him up the backside in each step. It also enables the rider to become a suction device, lifting the horse’s back and also getting those belly muscles to shorten. Just as it is tiring for the horse to hold his neck correctly, so it is tiring for the rider who uses isometric contraction. It is a far cry from ‘just sitting there’ – even though the fit riders who do this instinctively might well tell you that they are ‘doing nothing’!

If you compared this picture with one of Carl Hester, you would see a difference in the quality of the two men’s bodies. But I doubt if you would have realised that this stems not just from their make and shape, but from the difference in their muscle tone, and in the degree of isometric contraction they are each using. This determines their varying abilities to match the forces generated by the horse’s movement. This is a dimension of riding which we neither see nor recognise, and it is, in effect, a cultural blindness which I am attempting to illuminate. I live in hope that one day the horse world will learn to see biomechanics in action, and to understand the key issues of riding.

Carl, for instance, would be bearing down, which alters the muscle use in the front of his body. He would also have much better use of latisimuss dorsi, a big sheet of muscle which runs across the back and down the sides of the rib cage. This muscle is a big part of ‘using your back’, and to learn to access it, put your lower arm in a riding position, and pull down your shoulder and elbow on that side. At the same time, reach across the front of your body with the other hand, and you will find that you can get your fingers around the muscle just below the back of your arm pit. You can feel it bulk out, and the stronger you are, the bulkier it will become.

If you can find a willing partner (who is not embarrassed to grab your arm pits!) stand in a riding position but with one foot slightly in advance of the other, and pull down your shoulders and elbows. Get your friend to stand behind you, to put her fingers around both of your ‘lats’, and to grab hold of you. Meanwhile, try to pull away from her resistance, and sustain this for a while. Once you have had this feeling, think as you ride of pulling away from an imaginary person who is floating along behind you. This will help you to generate a force that acts in a forward direction, and this will enable you to stay ‘with’ the horse instead of being towed along by him and/or pulling back on the reins.

Using ‘lats’ well would help our rider in the photograph. I am not saying that it will automatically reorganise this horse’s muscle use; but without bearing down and accessing ‘lats’, the rider will not change the status quo. It will take very skilful riding to get this horse to change the mechanics of his movement – but I am sure that this is possible, and wish the rider good luck.