Last month I was lucky enough to attend a lecture demo given by Gillian Higgins, founder of Horses Inside Out (www.horsesinsideout.com) at Vale View Equestrian Centre. The focus was on posture for horses and riders and particularly focused on the horse’s back, both anatomically and in relation to its role in helping the horse work correctly. A lot of it was a practical demonstration using her famous ‘painted horses’ techniques so was best seen and appreciated (literally) in the flesh but below is a précis of my notes from the night. This article covers the first part of the demo focusing particularly on the horse and how its back posture is influenced.
First of all the vertebral structure:
7 cervical vertebrae – these have the biggest range of movement and sit lower within the neck than most people realise
18 thoracic vertebrae – these are what we sit on and where the ribs attach
6 lumbar vertebrae – what equates to the ‘lower back’ in people. There is very little movement through this part of the spine
5 sacral vertebrae which are fused to form a continuous unit
Caudal vertebrae – these extend to form the basis of the tail. Movement of these can affect the movement of the rest of the spine.
The back has evolved to carry the weight of the guts which can comprise 150kg of a 500kg horse. It has evolved to sling weight below it, not to be sat on from above. The spine has evolved to lie flat or curve upwards. When you put weight on it from above (eg. saddle and rider) this pushes the spine downwards the ‘wrong’ way. As a consequence the dorsal spinous processes (which protrude upwards from the spine) get closer together. Any muscular weakness will increase this extension of the back and affect performance therefore it is very important to ride horses in a way that promotes and maintains a good back posture.
Back posture in horses is influenced in 4 main ways:
- Via the spinous ligaments. These start with the nuchal ligament which runs along the top of the neck and which is continuous with the supraspinous ligament running along the back. The neck muscles of the horses alone are insufficient to raise the weight of the head and the nuchal ligament is vital in this role. Positioning of the head and neck can therefore extend or flex the back. Here Gillian gave a very effective demonstration. She lay a stick along the horse’s back and raised its head. As she did this the back hollowed and arched away from the stick. She then lowered the horse’s head and the back became flat and the dip under the stick disappeared. Try this at home. It’s so obvious and once you see it I guarantee a lightbulb will go on in your head! However when you add the weight of a rider, lowering the head alone is not sufficient solely to maintain good back posture.
- Hind limb attachment and positioning. The sacro-iliac joint, although capable of very little movement, is responsible for transferring the forces generated in the hindlimbs to the spine. The lumbo-sacral junction (LSJ) is the place in the spine, excepting the neck, where there is most movement. This joint dictates the horse’s ability to bring its hindlimbs under the body – imagine the classic sliding stop of the reining horse. If the LSJ is flexed the stifle flexes (ie. moves under the body). If the LSJ extends (eg. by adding the weight of a rider) then the stifle also extends (ie. moves out from under the body). Therefore you MUST bring the hindlimbs under the body to potentiate flexion of the LSJ and improve back posture.
- The thoracic sling. There is no bony attachment of the forelimbs to the horse’s body. As the supporting muscles of the thorax are recruited the withers rise. This is really important for putting the base of the neck into the correct position.
- The flexor chain of abdominal muscles. These are below the level of the spine and in front of the hindlimbs. Therefore contraction of these muscles creates flexion of the spine and hip and lifts the back.
Saddle position is also important for posture. The point of the tree must be at least 2-3 fingers behind the scapula to allow full movement with each stride. At the back of the saddle it must still sit on the thoracic vertebrae as there is movement between these and the ribs. If it sits further back than this on the lumbar vertebrae, where there is no movement between the vertebrae and the lateral processes, then pressure can build up.
Joint health can also influence posture. Joints need to be used to maintain their full range of movement.
Walk – this produces the greatest degree of spinal rotation of any gait because there is no moment of suspension. That is why walk is so important as part of a warm-up. There is also a large movement of the pelvis produced, both rotation and lateral movement, which also affects the spine.
Trot – This is a symmetrical gait and uses the back and abdominal muscles to reduce movement of the spine. In the moment of suspension the back goes into slight extension – the abdominal muscles work to reduce this. Most movement in trot occurs in the hock, stifle, elbow and carpus.
Canter – in canter there is asymmetrical movement of the limbs which results in flexion and extension of the spine. As the hindlimbs come under the horse on each stride the back rounds. The abdominal muscles contract together on both sides. Canter is important for the warm-up as it is the only gait where this happens.
I am probably doing Gillian a disservice with this article as so many of her points were illustrated by the muscles and bones painted onto the demonstration horses. Hopefully I will have whetted your appetite to find out more about how and why your horse moves as it does – it really does make sense when you see it in action and it can help you formulate a more intelligent schooling plan. Although I am familiar with all the anatomy covered (I really shouldn’t be in my job otherwise!) I rarely sit down and think in depth about how moving one bit influences another. I can only urge you to attend one of Gillian’s demonstrations, or at the very least to buy and read one of her books (I would highly recommend Pilates for Horses or Horse Anatomy for Performance). Go on, your horse deserves it!
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