Sorry about the random order of these, but that is how they seem to present themselves in lessons. This time it was leg-yielding: a movement, along with turn on forehand, taught early on in the horse's training. It is done with lateral aids ("baby aids") which are same leg, same rein, same side, as opposed to diagonal aids which are inside leg to outside rein. These movements are very rudimentary and have but one real goal which is to teach the horse to move away from the leg. The rein helps the leg on one side because whichever rein the rider pulls on, the haunches move the other direction. The rider sits in the middle of the saddle. It is not seat-yielding or weight-yielding. It is LEG-yielding. While the goal is to keep the horse relatively straight and parallel to the long side, it is still a movement bent opposite of the way the horse is travelling. This is a very important detail! It is precisely why the rider should NOT sit to the inside of the bend in leg-yield. Basics are the foundation upon which all future progress up the levels depends. We have all seen and heard stories of riders "hitting a brick wall" and not being able to move up the levels because of something done incorrectly in their basics. This is one of those things. It might help in the moment, but it will wreak havoc later when half-pass and other movements bent in the direction of movement are expected. The horse is totally confused when a rider first asks it to move away from seat and weight, and then expects it to move under the seat and weight in the much more advanced collecting exercises. Those exercises, if accomplished at all, become stilted and lack reach. Also, leg-yielding, done incorrectly, teaches the horse to "escape to the outside."
It is best to do it right in the first place and not use "tricks" to get it done. Don't use seat and weight to "push" a horse where you want it to go! That is not LEG-yielding. This has other consequences as well. Rider position suffers. And if I had a nickel for how many times a rider thumps on their horse and says it's because it won't listen to their leg. Well........?!?! I am aware that horses don't always cooperate, but could it be poor leg-yielding, perhaps? In a yielding to the leg, the inside leg and hand work together with the inside leg back. The seat is even and level and makes sure the horse gains the same amount forward as it does sideways. It is in half-pass (traversal) that the inside leg is forward, the outside leg is back and the weight is more into the inside heel without leaning or collapsing. The bend is in the direction of movement, and the aids are diagonal (inside leg to outside rein). It is a much more sophisticated movement. These two movements are very dissimilar even though they both go sideways and forward. Don't make more out of leg-yielding than it is. It is for controlling the haunches of young or green or messed up horses. Period.