It’s a classic exercise to introduce leg yield, and can help increase a horse’s bend, but I find that spiralling in and out on a circle can encourage bad rider habits to form and is so often detrimental to both horse and rider, rather than achieving the desired effect of increasing the engagement of the inside hind leg.
The basis of the exercise is that you establish a twenty metre circle before spiralling in towards the centre and then spiralling out again.
I begin teaching this exercise by standing at X, and asking my rider to ride a twenty metre circle from either E or B. We spend some time establishing the roundness, and identifying points where their horse is liable to drift out (usually at E and B), or fall in (usually as they cross the centre line). Then I ask them to slowly decrease the size of the circle by moving the horse’s outside shoulder in first. This reduces the rider using the inside rein to pull their horse onto a smaller circle, and encourages the use of the outside leg. Decreasing the circle slowly requires more balance and more subtle aids. The inside rein opens slightly to indicate moving across whilst the outside leg pushes the horse over, outside rein prevents the horse overturning with their head and supports the outside shoulder. The inside leg maintains the correct bend, and the rider turning their shoulders into the circle with their weight in their inside seat bone helps the horse stay in the correct bend.
By spiralling in slowly, and almost adopting a shoulder fore position the horse will bring his inside hind leg under his body, propel himself forwards more correctly and feel lighter and more engaged. The smaller circles require more suppleness and balance from the horse. I often tell my rider to stay on a certain sized circle, or not to spiral in any further because I can see that the horse has reached their limit in terms of suppleness so are better staying at this point instead of going smaller but losing the quality to their gait.
From the small circle, I ask the rider to sidestep out onto a bigger circle before riding a few strides on this circle and then sidestepping again. This makes a series of concentric circles, rather than a spiral. This helps control the movement and keep it correct. By only leg yielding a couple of strides at a time the rider doesn’t lose their horse’s outside shoulder, the inside hind continues to push the horse sideways so they stay engaged. The rider’s outside aids continue to be effective and the horse stays balanced.
Some horses are more likely to rush back to the track, so pulling themselves across in the leg yield from the outside shoulder. In this case, I get the rider to “ride smart”: as they start to ride towards E or B they have to apply the outside aids before their horse drifts and takes control of the movement, and then ask for the leg yield as they move towards the centre line, when the horse has no inclination to fall out. This ensures that the leg yield comes from the rider’s aids and is not the horse anticipating.
Ridden correctly, the horse becomes more supple and engaged, and it is an excellent warm up exercise for gently stretching them and unlocking and tight or resistant spots. I find it incredibly useful when Phoenix gets her knickers in a twist (when the wind blows or the something is out of place) as when I move her body around subtly she releases through her barrel and becomes more rideable. It’s also useful for identifying a stiffer side in rider or horse, as well as fine tuning the rider’s aids and control through a movement.
So often I see the spirals being ridden badly; the head and neck over bending as the horse spirals in, with too much inside rein, and them falling rapidly through the outside shoulder in a race to get back out to the bigger circle. Which doesn’t help engage the inside hind leg, or promote the rider using their outside aids correctly or effectively.
Next time you ride this exercise, try changing your approach to it, and critique yourself to make sure you aren’t letting either yourself or your horse cheat by drifting in and out on the circle. How many times do you pass B as you move in or out? Can you increase that number? Slowing down the movement requires more balance and more obedience from your horse.