You need a 6kg/8kg or 9kg ball. The perfect distance between the wall and the ball: Take the ball, stretch your arms forward until the ball touches the wall. This is the correct distance. Feet shoulder-width apart. During the downward movement, the hips should be below the knees. Push the ball as high as possible against the wall and at the same time get out of the bend. When you catch the ball, return to the bend at the same time.