Q: What is a swayback?
A: A swayback is a hollow back, that has a dip between the withers and loin area. This type of back is usually too long and excessively flexible, so develops a sway because the ligaments become weak and sag. Interestingly most of the strain on a sway back is on the ligaments rather than the bony column of the spine itself. Horses with sway-backs also tend to have high head-carriage, although a horse with an abnormally high head carriage can appear sway-backed, even if he is not.
Swayback can be a congenital issue, or it is thought that it can be caused by mineral imbalances in the diet when the horse is young and growing. It can also be the result of aging, especially if the horse has been worked hard. Older mares often develop a sag in the back after carrying many foals.
In order to carry weight effectively, horses need to be able to round their backbone a little. With a swayback a horse is unable to do this effectively, and this makes the back weak and liable to damage. These backs are also difficult for saddle fitting as the saddle tends to ‘bridge’ the back, making maximal contact just behind the withers and in front of the loins rather than distributing the weight and pressure evenly along the whole back. This obviously exacerbates the damage to the back when the horse is ridden. A swayback also places the rider too far back behind the centre of gravity, which can interfere with the horse’s ability to work and makes it nearly impossible for him to collect. Swayback is also a problem for speed. Much of the thrust and power of the hind legs is wasted because it can’t be transferred forwards unless there is some rigidity to the spine.
Swayback horses therefore commonly break down easily and tend to become sore quickly from the extra stresses and strains on their backs.