Pullovers are a back movement. Period. Functionally, the pectoralis are used to adduct the humerus (bring your arms together.) Since your arms remain in a fixed plane throughout pullovers, there is no way that can happen. Old-school thought (in the 60s and 70s) was that pullovers could expand the rib cage and make your chest "broader." This is also a myth. The cartilage in your rib cage can not be made to grow significantly after Tanner stage 5 growth. Keep the pullovers with back. -EK