Which fuel does the ATP-PC energy system primarily use?

Which fuel does the ATP-PC energy system primarily use?

• A. Creatine phosphate
• B. Glucose
• C. Glycogen
• D. Fatty acids

Answer: (A)

During a very short, powerful effort, energy comes from the phosphagen system, which relies on creatine phosphate stored in muscles. When quick ATP is needed, the phosphate from creatine phosphate is donated to ADP to reform ATP, using the enzyme creatine kinase. This happens rapidly and doesn’t require oxygen, giving an immediate burst of energy. Because the stored creatine phosphate is limited, this system only powers maximal effort for about 8–12 seconds before other systems take over. Glucose and glycogen feed glycolysis for longer high-intensity actions, and fatty acids are used mainly in longer, lower-intensity aerobic work. So the primary fuel for this energy system is creatine phosphate.

During a very short, powerful effort, energy comes from the phosphagen system, which relies on creatine phosphate stored in muscles. When quick ATP is needed, the phosphate from creatine phosphate is donated to ADP to reform ATP, using the enzyme creatine kinase. This happens rapidly and doesn’t require oxygen, giving an immediate burst of energy. Because the stored creatine phosphate is limited, this system only powers maximal effort for about 8–12 seconds before other systems take over. Glucose and glycogen feed glycolysis for longer high-intensity actions, and fatty acids are used mainly in longer, lower-intensity aerobic work. So the primary fuel for this energy system is creatine phosphate.