FOOD FUELS
What is the preferred fuel source for high‑intensity exercise?
Carbohydrates.
What does ATP stand for?
Adenosine Triphosphate.
What fuel does the ATP‑PC system use?
Creatine Phosphate (PC).
What is the fuel source for the anaerobic glycolysis system?
Glycogen.
What fuels does the aerobic system use during exercise?
Carbohydrates and fats.
Carbohydrates are stored in the body as what?
Glycogen in the muscles and liver.
ATP breaks down into ADP and what?
Inorganic phosphate (Pi).
How long does the ATP‑PC system typically last?
0–10 seconds.
What by‑product is produced when glycogen is broken down without oxygen?
Lactic acid.
What are the by‑products of aerobic metabolism?
Carbon dioxide and water.
Which fuel provides the most energy but requires the most oxygen to break down?
Fats
Why is ATP only stored in small amounts in the muscle?
It is a heavy compound.
How long does it take to fully replenish PC stores?
About 3 minutes.
Lactic acid breaks into lactate and what fatigue‑causing ion?
Hydrogen ions (H+).
At what point does the aerobic system become dominant?
After about 1–2 minutes of continuous exercise.
Protein is mainly used for what two purposes?
Growth and repair.
What process rebuilds ATP after it is used?
ATP resynthesis by the energy systems.
Name one sport or movement that relies heavily on the ATP‑PC system.
Examples: 100m sprint, shot put, tennis serve.
What effect do hydrogen ions have on muscle contraction?
They lower pH and inhibit calcium release, reducing force.
What is the definition of energy system interplay?
All 3 systems working together to supply ATP.
In extreme-duration exercise, which fuel may be used when carbs and fats run out?
Protein.
What determines which energy system is dominant during exercise?
Intensity and duration.
Why is the ATP‑PC system the fastest system for producing ATP?
it uses simple chemical reactions and does not require oxygen.
What is the typical duration where this system is dominant?
10–75 seconds.
Why does the aerobic system contribute to PC restoration during breaks?
It provides ATP using oxygen, allowing PC to be rebuilt.