eclipse_images / Getty Army bases, city parks, church gyms, and state prisons are full of guys with wide shoulders , thick backs , and big chests and arms . And if you asked them what they do to achieve this look, you’d always hear the same answer: pullups and pushups . These simple, timeless exercises work the entire upper body and can be performed virtually anywhere. We’ll show you how to take full advantage of these moves, along with some of the most effective variations , to build your back, arms, chest, and shoulders—no weights (or jail time) required. [RELATED1] How it works When you do a pullup , you engage your lats, mid-back, rear delts, biceps, forearms, and core. Pushups train your chest, shoulders, triceps, and core. So between these two movements, you’ve got the whole upper body covered . Another benefit of body-weight training is that it’s low-impact . As a result, you can train more frequently than if you were using heavy weights, and the mo...