By placing your hands in different areas and tweaking your technique while doing push-ups, you can vary and target different muscles. First of all, with doing any type of push-up, besides stability work that is being done by the core, you are really working your chest (pectoralis major), your shoulders (deltoids), and your triceps. With a wider hand base and the elbows out, the strongest muscle out of the group, the pectoralis major, does most of the work, with the shoulders and triceps acting more as assistants. You should be able to complete a greater number of push-ups using this technique. If you're interested in targeting your deltoids and triceps more, however, you can move your hands closer in together, and keep your elbows close to your body. Though you won?t be able to complete as many repetitions, because the deltoids and triceps are not as strong, these smaller muscles will do most of the work.