Hi my name is Oliver James I am here to discuss about what muscles do pull ups work with you. Pull ups are a great exercise for targeting multiple muscle groups at once. The primary muscles worked are the latissimus dorsi, or lats, which are the large muscles in your back. The trapezius, or traps, are also worked, as well as the biceps and forearms. Pull ups also engage the core muscles, including the rectus abdominis, transverse abdominis, and obliques. When performed with proper form, pull ups can be an extremely effective exercise for building strength and developing muscular endurance.