I would love for a critique on my horse Tres and I. This jump is either 2’9 or 3ft. In particular, I could use some advice on supporting my upper body over fences. I tend to let my back arch instead of supporting with my abs and staying up off his neck. Advice on how to fix this would be great!
Hi. In the first photo, your upper body is ahead of the motion, causing your lower leg to swing back. You want your seat to be more in the middle of the saddle and not over the pommel. Your horse has dropped his shoulder some causing his knees to hang. In the second photo, things look much better. You could shorten your stirrups a hole and support your upper body by holding yourself up more through your thighs. Don’t let your thighs collapse over the jump. This is very minor in your case. I like your release much better in the second photo. Your horse is much better with his knees in the second photo also. Nice job.
A good exercise is to practice the two-point position at the trot for long distances without resting your hands on his mane. This will strengthen your leg position and your core muscles. This will help your position over the jump.