Pulling with a barbell on top is usually considered an exercise for the back, but during this movement, the muscles of the entire body are active. The muscles of the middle and upper back (the broadest back muscles, rhomboid, trapezoid, and posterior deltoid muscles) together with the biceps provide a pulling movement. But the core, glutes,spine extensors, and hamstrings also need to work to stabilize the body while pulling the barbell up.