I hope everyone understands the value of (good) loping circles but there are so many things you can do with the circle as the basis. Of course, your circles need to be consistant in size and speed, with the ability to speed up and slow down. The circles need to be as round as possible - not elipses or ovals. Once you've established good loping circles then you can really start having fun!
I always teach my horses to spiral into a small circle and then spiral back out into a large circle. I push out the circle out with my inside leg, keeping the horse's whole body arced nicely, then push the horse back into as small a circle as he's comfortable with, then repeat.
I teach all my horses to counter bend when loping circles, again, making sure to move the rib cage, not just the head and neck. About this time in a horse's training I will also introduce simple lead changes. I always do simple changes before teaching flying changes as this helps a horse to collect up and get ready for the advanced maneuver of a flying change (assuming I choose to teach them and they're able - some horses just aren't built to do a flying change comfortably).
I start doing counter-canters about this time as well. I deliberately lope the horse into an egg shaped counter-canter pattern, exagerating my cues. As the horse gets better with this, you will not have to use such obvious cues and your egg shape can potentially become a counter-cantered circle. (Email me if this doesn't make sense and I'll help you visualize it!) Counter-cantering really cleans up a lope and helps slow a horse down as well. It does this by really lifting the back and shoulders and forcing a horse to use the leading inside leg.
I also like to lope circles into the wall, using the wall as a tight barrier on one side of my circle. This helps a horse drive up underneath himself, without me having to force the issue, just some encouragement with my leg is all that is needed.
I really like a stop, pivot, lope off routine too. Usually I pivot to the outside and lope off on the opposite lead, being careful to keep my circles the same size and the horse's shoulder up, with their body straight in the transition.
Another exercise I sometimes use is to ride a circle then ride a straight line out of it and then build another circle (visualize a P or a 9, with the tail of the nine straight though! - the top is your circle, and the leg of the P or 9 is your straight line, then at the end of the leg, build another circle...). Your horse should line his shoulders up straight whenever he comes out of your circles. I make sure my horse is not on the wall when I do this as the wall will support the horse and I want to make sure the horse is straight in the shoulder from my cues and my leg and not just from the support of the wall, and I want him to stay straight until I arc him into my next circle.
An advanced maneuver that is very good for Western Pleasure horses is to lope squares. The trick here is to have very straight lines connected with sharp 90 degree angle turns. This helps a horse to lift his shoulder but don't try this unless your horse gets very good with all the circle work I've described and remember that you'll really have to ride the rib cage to accomplish this!
Another execise I like is to put my horses on the rail at a lope and then flex them off the bridle both to the inside and outside. Be careful to keep their shoulder up and straight and just flex them in the poll, not the middle of their neck. Having a horse work the wall with his head and poll flexed to the outside will really slow a horse down but again, make sure he has good basic circle work before you introduce this.
It takes quite a while to accomplish everything I've described here, probably close to a year for most horses but it's well worth it. Don't try all of these at once and don't over-ride any of them but add them patiently and carefully into your routine and I think you'll find they're a challenging way to keep your horse - and you - in tune! Talk to you next week! JD