On that bass-akward leg cue topic. I know, right? It’s so hard to do what Brannaman (and some of his students who have taught me while mounted) do if you were taught to ride as we were!
But here’s my take on that: IMO, the sliding your inside heel way back is not about an aid on the horse’s abdominal line on the inside. That is where I see these tall men touching their short horses with a spur. The point is not about touching the horse with the spur back there Rather, I think that leg position is about making absolutely sure that the inside sitting bone is light and off the horse. Remember that lots of western riders want to kick their feet out in front of them. If you had contact in your inside hand and had that same toe out in front of you, chances are, you’d be resting hard on that inside sitting bone. Your knee might not be straight and locked, but I’ll bet you have some tension in that leg and are bracing against the stirrup a bit. And if that is so, your sitting bone does not feel like something a horse wants to relax his back into.
I discovered this just by doing as I was instructed with a pretty good, nice-guy of a student of Brannaman’s who was local to me when I lived in Oregon’s Willamette Valley. I knew that this was one piece of his training that was too far off my over-all goal for my dressage horse. So I tried to figure out a way to ride here and get the right turns done without kicking my heel back. What I did worked ok. But then coming from English world, I have pretty good awareness of my sitting bones and how to move my leg in a way that does, or does not put weight on a sitting bone. I talked about it a bit with the pro and, being a nice guy, he didn’t tell me I was way wrong about the “real” aid or effect accomplished by moving that inside leg so far back. But I explain all this so that you are aware that I’m just making my own hypothesis about it.
If I ever get a dedicated bridle horse project (and a guru to go with it), AND if I learn why this inside leg way back is logical or worth doing, I’ll let you guys know.