Originally Posted by Saddlebag
Check her back. If she is uncomfortable that may be how she is expressing it. She didn't fuss when your mother was on. Was she bareback or saddle? Is she lighter than you. Perhaps she was more balanced and not creating one-sided pressure.
She did fuss when my mom was on. Until I started lunging her at a fast trot and changing directions every half circle to circle. She was under saddle both times. This is a habit of hers, she did it with the old owners/trainers too. And the girl who started her is equine major. To her, it is like cribbing in a sense. She has been seen. Her teeth and back are fine. She is sound. My mom also weighs around the same as me. So it isn't weight. And my mom is very novice. My seat, balance, aids, are all better then hers. She is very clumsy with aids, and slow to release pressure if not told when..