Push-ups work more than just the arms. Correct posture while doing a push-up requires a straight spine. Holding the aligned position works back muscles and can help women avoid back weakness that leads to curvature of the spine. The abdominal muscles should remain taut as you perform push-ups, providing a good ab workout, leading to better posture and reducing the waistline. Chest muscles also receive a workout during push-ups and can help to alleviate sagging breasts. Sagging skin on the upper arms are one of the most dreaded conditions for women as they age. A regular routine of push-ups, coupled with a healthy diet, can help to prevent those flapping underarms completely. Arms and shoulders receive the greatest workout from push-ups, providing women with toned arms to show in sleeveless tops and dresses.