Perform on court resistance bungie tennis drills. Teaches tennis player to stay down low and balanced before hitting. Resists player in side to side motions as well as moving forward and back to the ball. After completing drill, player automatically gets down low and uses legs to stabilize before striking ball therefore achieving more powerful groundstrokes with greater balance. Go on the field for resisted and assisted running drills and resisted vertical jumps. 8 feet long and stretches to 16 feet.