The idea being to have the horse lift off the your inside leg and shift his balance into the outside rein. With his weight to the outside, he can then bend and turn to the inside without losing his balance. In addition, you have a great half-halt ready in the outside rein.
Well in my last lesson, inside leg-outside rein was turned on its head.
See, in the shoulder-in to the right, my horse likes to fall onto his inside shoulder. No amount of half halting will get him to lift. No amount of pushing from behind will, either. He just rushes, and falls harder. I've ensured that I am pushing him into the outside rein, and am maintaining the bend with the inside leg. Still he falls in.
He's protective of his left shoulder, see. The barest of touches with the left rein, and his shoulder will dart over. He's quick to throw a fit rather than lift up his right shoulder and have to fill up his outside left.
"If he still falls in after you've brought the shoulder around with your outside rein, don't be afraid to take that outside shoulder out slightly." That's my trainer, full of excellent advice.
I guess when inside leg to outside rein fails you, it's okay to think out of the box and create a new training tool.
So here's what I do...
The minute I realize inside leg/outside rein isn't working, I increase the bend in my outside elbow and carefully take my outside hand OUT. The feeling here is one of guiding the outside shoulder down the line, and widening the front feet.
"He's past pushing into that rein. If you push more with your inside leg, you're going to push him past your outside rein, and past his balance point."
Huh. So no extra inside leg, just outside rein. Interesting...
Guinness reacts to a leading outside rein by straightening slightly, then shifting back to take his balance off his front end. With his weight shifted back, he takes a bigger and wider step with his outside front. Finally, he fills up the outside of his neck and is able to step forward with the inside hind and flex nicely through his poll.
The big thing to remember here? Make sure to keep the inside leg on. You don't want to take it away completely, just not increase its push. The inside leg should stay long and draped on the horse, asking for the bend to stay and the haunches to stick. The other important factor is your weight aid. You'll want your weight more on your outside seatbone. In Guinness' case this can sometimes be so dramatic that I lean off to the outside. A less stubborn and crooked horse will need a less obvious aid. Experiment as needed.
So, using the outside rein independently to place the shoulder. Neat! Another tool for the box.
To apologize for a lack of photos illustrating this post, please enjoy this sequence of photos demonstrating me