[QUOTE=ideayoda;7915526]
It is not as much the saddle (since a rider can be very secure in both saddle) but rather the too open joints (too long a stirrup and too long a leg w/o all the joints being elastically stretched into the heel). And it is also a question of whether rider is over the center of motion vs behind it, it is the later the buck will propel the rider out of the saddle.[/QUOTE]
Yeah. I think it’s the straight legs and no room in the (bucket) seat that form the ingredients of a fall when a horse starts to buck.
FWIW, I ride an an uber-flat, open old Stubben Tristan special. It’s the Prix des Nations of dressage saddles. I have not fallen out of it yet. But judging from what I feel when I have ridden some bad canters in it, I think the open seat helps me: No matter where I land, there’s still a place for me in that saddle. My open hips, knees and ankle joints feel like they really don’t help me with riding anything bigger like a buck.
Not looking forward to the first time I do have to ride some broncing in a dressage saddle.