Build An Incredible Back With This 30 Minute Workout. 6 Best Back Workout and Exercises for Thick, Wide Back. Arched Wide Pull Up. arched pull up. Take a wide grip and do a pull up while keeping your back arched. Arched wide grip pull up will work primarily the lats, teres major, posterior deltoid and middle traps. How to develop thick and wide back muscles - explained! . Find out 6 back exercises with guidelines and tweaks for better, growth!