Leg yielding on the circle is executed similarly to leg yielding on the long sides of the arena with the horse facing into, and being flexed to the inside of the circle, with a slight bend to the horse’s body following the curve of the circle being ridden. The execution becomes very close to shoulder-in. To leg yield on a circle increases the degree of difficulty because the hind leg will engage more. They have to step on the circle line and the rider must apply the forward-sideways driving aids inside as well as preventing the horse from evading to the inside of the circle (with steps like travers), while the forward guarding aids on the outside will prevent the horse from falling outside of the circle.
Christian Thiess ( Excerpt from The horse magazine)
It is important to understand basic work before collection. Without the basics, you will not acquire a true collection. The horse is taught to respond to quiet, correct communication of rider’s aids, which will enable him to have correct bend which leads to straightness.
If the horse is not supple and stiffens against the inside leg when performing leg yield, you will not have a successful shoulder in, which is the foundation for all supple work in preparation for higher level movements. The leg yield has to be performed with the hind leg crossing or the horse will just become inverted and use the outside shoulder to move sideways, evading the gymnastic value of strengthening the inside hind. It is only after the horse accepts the sideways movement can he be “straightened” with inside leg and outside rein.
Half halts with the seat and outside rein must communicate coming from behind, over the back and to the hand without losing energy or impulsion. Rushing the horse forward to strong bit pressure, contracts the back muscles and has the opposite effect of creating a strong topline.
Practice this by feeling if your horse steadies your weight slightly to the inside when moving sideways or throws your weight in the opposite direction (inverted use of back muscles)
“ Correct discovery depends on the understanding that right and wrong are relevant concepts defined by the horse's point of view. Only that which benefits the horse is right and all that damages or destroys the horse is wrong. Therefore, the horse verifies the quality of the rider’s work. “ - Charles De Kunffy