The main way the army breaks down recruits is through nonstop, punishing exercise all day long. Picking up a duffel bag and running around in circles. Constant running. Drill sergeants sounding off: “Front leaning rest position. Move!” Tens of thousands of push-ups. Pull-ups. The side straddle hop. Every exercise approved under the old field manual, and even some made-up “home brew” exercises.
