The best way to improve vertical jump is JUMP all the time. Jump without weights, jump with weights, run sprints just do anything to increase power and explosiveness in the legs. Having strong abs help to as you use a lot of legs in jumping. That's what a lot of those programs incorporate.
My favorite thing to do is find something like a ceiling, tree branch, etc that you think is an inch or two out of your jump reach and keep jumping until you can grab it. Then once you can do that move onto something higher.
My favorite thing to do is find something like a ceiling, tree branch, etc that you think is an inch or two out of your jump reach and keep jumping until you can grab it. Then once you can do that move onto something higher.