ATP-PC system

The ATP-PC system provides quick energy for short, intense activities like sprinting or heavy lifting. It uses stored molecules in your muscles—ATP (adenosine triphosphate) and PC (phosphocreatine)—to produce energy rapidly without needing oxygen. When you start intense movement, these molecules break down to release energy almost immediately. However, their stores are limited and depleted quickly, usually within about 10 seconds. After that, your body shifts to other energy systems for longer activity. The ATP-PC system is essential for explosive movements that require maximum effort over a brief period.