While in the sitting position on the floor and the athlete's back is against a common wall. The knees are locked so the calves are in contact with the floor, the adjustment to the athlete's size is then obtained by simply pulling the nylon straps to provide the tension. The calf muscles, hamstring and Achilles tendons are stretched and pre-loaded; then by applying pressure with balls of the feet, the specially engineered tension springs react with an opposite calf building resistance of up to 1000 lbs.+  This overload delivers a workout like no other device or platform shoe can. The Sky-King Calf Isolator builds the calves in addition to the arches of the feet and stretches the Achilles tendon, through repetitions and isometrics. Turn the feet in and adjust the cross member shorter to build the outer calf muscles and outer ankles; turn the feet out and adjust the cross member longer to build the inner calf muscles. The total calf, and foot arch exercise device is now being provided to you and your teammates, and will deliver increased vertical jump, increases foot quickness, and makes any athlete more explosive.