My horse is a greenie and so for the past year or so we have been keeping the jumps relatively small (under 2'6) Well he has recently progressed rather quickly and so my trainer has been bumping the jumps up a bit. (3' courses or so) Well, I haven't jumped that high since I got my own horse two years ago and have come to realize that my horse has a NICE jump. Good for him, not so great for my equitation. Over the bigger fences I have a really hard time staying with him (get jumped out of the tack) and I also don't stay in jumping position for long enough over the top of the jump. Unfortunately I am just about maxed out time and money wise with my one lesson a week, but 2-3 more times on my own per week and sometimes incorporate a bit of jumping into our flatwork. Any tips for helping me get over this?
Also getting your leg strong and in the correct position should be helpful. Try standing in the stirrups (straight up over the pommel) to get your leg in the correct position. Don't move it when you sit down or go to 2-point. Lots of 2-point is helpful as well. When you feel really solid in your 2-point, try transitions in 2-point. Posting for 2 beats at the trot is also helpful and surprisingly difficult. Good luck!
I would suggest riding without stirrups and/or lunge lessons this will help you find your balance while strengthening in a non strenuous way for your horse as well!
This! If you take the stirrups completely off of your saddle and do at least two rides a week like that you will be amazed at how quickly you become ridiculously strong!!! After oogling PNWJumper's photos of jumping huge jumps without stirrups for like, an entire year, I went I need to do that too, but over lower jumps. I was amazed at how much better it made me. And, best of all, it's free!