Which component is NOT part of the energy systems used during exercise?

The cardio-respiratory system is not classified as an energy system used directly during exercise. Rather, it refers to the body’s ability to transport oxygen and nutrients to the muscles and remove waste products, functioning as an overarching system that supports the energy systems.

In contrast, ATP-CP (adenosine triphosphate and creatine phosphate) is part of the phosphagen energy system, which provides immediate energy for high-intensity, short-duration activities. The anaerobic energy system relies on the breakdown of glucose for energy without the use of oxygen, primarily for activities lasting from about 10 seconds to 2 minutes. The aerobic energy system, meanwhile, uses oxygen to produce energy for prolonged, lower-intensity exercise.

Understanding the distinction between these energy systems and the role of the cardio-respiratory system helps clarify their interrelations and functions during various activities.