I can't quote since it's written in swedish, but I know at least 3 people who had to start riding bareback because of an illfitting saddle, and their horses suddenly gained much more muscles and worked better with them.
I woas going to show pictures, but can't find them in the bazillion of threads.. -_- but I can PM the rider and ask for before-after photos?
So either the rider in your story doesn't ride very good in that aspect, or the horse got problems of another reason.
Originally Posted by moomoo
"A girl I knew rode her horse everyday bareback for a couple of months ( only about 30 minutes to 1 hr each day) but after a couple months of this he had pressure sores on his back. She was a very good rider and the horse was in good condition but over time was broke down to the point that she couldn't even ride him with a saddle, he spent several months on pasture rest to heal his back."
Even if you can sit the trot the motion of it is less 'flowy' and your seatcones still dig in every stride.