Core stength is built in this program. You could have powerful legs but never be able to get off the ground. If you have a weak core you will lose alot of your upward force.
Stability is very important in one's vertical jumping ability.
Stablizers allow the body move more fluidly which allows you to jump higher in the air. This program will force your body to recuit more muscle fibers on an explosive movement. The program uses compound movements at explosive speed to force your body to recuit more muscle fibers. You see every time you jump not all your fibers are being recuirted from. But after your body has adapted from this program you will recuirt more muscle fiber on every trip upward.