[QUOTE=carolprudm;8682389]
I would set up some ground poles, maybe 3 to start, a d sit until you get to them, post through them and sit when she started to get uneven.[/QUOTE]
If the horse is clunky and shuffling, I would not add ground poles to the equation - too much too fast. IIRC, OP you have this horse on trial for a week?
When I got my mustang, he didn’t know how to handle posting and since he was comfortable, I sat for a long time. I think that the posting might have made him feel off balance or made him think that I was off balance or something. Eventually I started posting and it wasn’t a problem and now I post or sit as needed.
My pony has less than 30 rides on her. The first time I trotted, I tried posting and she was a bit confused, so I sat (mind you, the first time trotting was just a few steps, not a long trot or lots of circles). The second ride I did a mix of posting and sitting. The third ride I was exclusively posting.
I would wonder about a 6-year-old horse that has been under saddle for three years but doesn’t understand posting. People who ride western post the trot, so unless the horse has a trot like a still lake, she should have had someone do the posting trot on her before now.
I would keep this in the back of my mind as a possible red flag for either previous training or the horse’s soundness. You had mentioned in another topic that she’s been through four owners so far? That’s a lot for a 6-year-old horse. Please don’t get too excited and really honestly evaluate this horse during your trial. Please also listen to your trainer’s advice.
It is a heck of a lot easier to buy a horse than to sell one.