Three different metabolic energy systems power your workouts — and your day.
Each burns a particular type of fuel at a particular rate — thereby affecting fat loss and muscle gain in a particular way.
- The adenosine triphosphate–creatine phosphate (ATP-CP) system, or phosphagen system, supports very brief, high-intensity activities like a single-effort vertical jump.
- The glycolytic system provides energy for activities of slightly longer duration and lower intensity like strength training.
- The oxidative system supports long-duration, lower-intensity activities like walking or distance running.
Here’s how each one works, and how to make the most of them all.