Just before snapping backup in the air, my speed is 50m/s. What is my kinetic energy just before snapping back up

Kinetic energy of anything is (1/2) (mass) (speed) ².

Your kinetic energy just before you snap back up (??) is

(1/2) (your mass in kilograms) (50 m/s) ² =

(1/2) (your mass in kilograms) (2,500 m²/s²) =

(1,250 x your mass in kilograms). The unit is Joules.