This movement requires something heavy, such as a barbell, sandbag, or cinder block, though anything of similar size and heft will do. Stand with your feet shoulder-width apart and bend your knees 15 degrees to 30 degrees with your heavy object of choice on the floor in front of you. Now, keep your back straight and bend forward at the waist until your torso is just about parallel to the floor. Take hold of your weight with your arms hanging straight in front of you and pull your shoulder blades back. Slowly raise the weight to your sternum, and hold it there for a moment while sticking out your chest before gradually returning to the starting position. Three sets of eight to 12 reps, four days a week, will strengthen muscles in the lower and middle back, which are important for standing and kneeling positions.