Part of it is that he is green and you are as well. Some horses just never develop into horses that jump well and some riders are lacking in proper instruction on how to encourage a horse to jump effectively and in correct form. I'd talk to your coach and see about getting an experienced rider to school him over jumps and put you on something that has it down so you can work on you and he can be working on him then put you back together when you both have a better idea of correct form and what it feels like and build from there.
Are you talking about overjumping? At some point given a high and or wide enough jump all 4 feet will be off the ground with the horse stretching across.
Edited to add: Do you mean "stotting"or what I we tend to call pronking. Jumping straight up with back curved and legs stiff? I see that more in bucking horses and have never seen a horse pronk over a jump as the movement is more so up than it is forward.
Last edited by QtrBel; 07-10-2019 at 07:49 AM.