check out airalert.com buy some strength shoes, calf raises, they all work. But if you fuck with plyometrics you could fuck up your joints but you will get your results. I did calf raises and I quickly noticed I increased my vertical. Just find some steps, stand on the end with your tippy toes and lower your body and excel back up my using your calves. You can do it with one legged, then switch after a certain amount of reps, then go back to the other and then to the other. After you've done each leg twice, do both legs, do all this with no rest.