COMMISSIONED OFFICER. Commissioned Officers are the managers, problem solvers, key influencers and planners who lead Enlisted Soldiers in all situations. Enlisted Soldiers perform specific job functions and have the knowledge that ensures the success of their unit's current mission within the Army.
The primary difference between chin-ups and pull-ups is that chin-ups are done with a supinated grip, palms facing in toward the exerciser. This sets up the mechanics so that chin-ups, while still primarily a back exercise, also provide a good arm workout, particularly for the biceps.
The major muscle groups used for chin-ups are the latissimus dorsi back muscles and biceps brachii arm muscles, but other back, arm and shoulder muscles assist the lats. Compared to pullups, chin-ups use the pectoral muscles more at the start of the movement and focus the biceps and forearms slightly more.