1. Cells produce energy in the form of ATP through various energy systems, including the ATP-CP system, anaerobic glycolysis, and the aerobic system. 2. The ATP-CP system provides energy for 2-10 seconds by resynthesizing ATP from creatine phosphate. Anaerobic glycolysis produces energy without oxygen for 1-3 minutes by breaking down carbohydrates. 3. The aerobic system provides sustained energy over 3 minutes by oxidizing carbohydrates and fat through the mitochondria and electron transport chain to produce large amounts of ATP. Together these systems power human movement.