I was recently asked this question for our local dressage newsletter, and thought I'd share my answer with you as well.
What was one of the toughest training issues you have had to deal with?
Training any horse in dressage is tough work. It's never easy. When I was starting out I always thought to myself if I had nice horses it would be easier. Then I got nice horses, and it was harder.
The biggest challenge for me was learning to teach horses how to accept my aids. It took a couple of very difficult horse to teach me this. Everyone talks about acceptance of the aids, but what does that really mean? To me, acceptance of the aids means the horse yields away from pressure in a relaxed and comfortable way, consistently, time and time again. It is also speaking to the mental state of the horse. Teaching acceptance to the aids is actually quite simple, but being aware of how much aid we give in a consistent way is difficult to do. Especially as we start introducing more complicated things like lateral work. We teach this by applying pressure, whether it's with a leg, seat or hand, and holding that until the slightest effort is made in the direction we want. Once an effort has been made in the positive direction, it's imperative to immediately yield and praise our horse. Initially, by yielding at the onset of effort on their part, we cultivate what I like to term "try." Cultivating try in our horses is an absolute must. We need our horses to try to figure out the progressively more difficult "problems" we challenge our horses with. If horses who are trying don't receive a reward or release from that pressure, they soon stop putting in much effort, as they learn that even if they do the right thing the pressure doesn't stop. I find most problems in training are the result of a lack of honesty to an aid.
When training horses I also think it's important to embrace problems. I find too many people think problems mean they are doomed and everything is off track. Steffen Peters loves to say problems are just training opportunities. The more mistakes my horse makes, the more I can correct that mistake, the sooner the horse will learn to do the right thing.
Embrace problems, and work on refining the acceptance to your aids, and every ride will be a good one!