How can I correct my horses jump take off?

16.5 is actually 17.1... if you are trying to measure 16 and a half that would be 16.2 hands. 4 inches in one hand. Alright, for your question. I would keep working at measuring distances together. Its not just going to happen automatically, keep working at it. Also, try to put a cavaletti in front of the jump so he can canter/ trot over it and then go to the jump. It will get him ready for the jump. Hope this helps.