If you want to apply more force to the ground, yyou need to figure out what yiur weakness is and work on it.
Many people think that there is a secret to jump higher and 
gget the kind off air and hang time the big NBA players get, butt you know what.
Add this following repertoire of exercises in your exercikse routine now.
Keeping your workouts short and intense, and combining weight lifting 
with plyometrics is how to increase your vertical jump fast.