ATP-PC System
What is the primary function of the ATP-CP system?
To provide immediate energy for high-intensity, short-duration activity (0–10 seconds).
What is another name for the anaerobic glycolysis system?
Lactic acid system
Which macronutrients are primarily used in the aerobic system?
Carbohydrates, fats, and sometimes protein
What is the body’s preferred fuel source for high-intensity activity?
Carbohydrates (glycogen / glucose)
What is fatigue?
The decline in ability of a muscle to generate force or power
Name the chemical stored in muscles that helps quickly resynthesize ATP in this system.
Creatine phosphate (CP or phosphocreatine)
What is the main fuel for anaerobic glycolysis?
Glycogen / glucose
Name the by-products of the aerobic system.
Carbon dioxide, water, and heat
Name the primary fuel for low-intensity, long-duration exercise.
Fats
Name one factor that contributes to fatigue in anaerobic glycolysis.
Lactic acid / hydrogen ions accumulation
How long does it typically take for CP stores to fully replenish?
Around 2–3 minutes of rest.
What is the main by-product of this energy system that contributes to fatigue?
Lactic acid (or lactate and hydrogen ions)
For activities lasting more than 2 minutes, which energy system is the predominant source?
Aerobic system
During prolonged exercise, what happens to glycogen stores if not replenished?
They become depleted, leading to fatigue or “hitting the wall.”
How does the body recover CP stores after maximal exercise?
By resting or low-intensity activity for 2–3 minutes
Give one example of an activity that primarily uses the ATP-CP system.
100m sprint, high jump, shot put, weightlifting
How long can the anaerobic glycolysis system typically supply energy for?
10 seconds to 2 minutes of high-intensity activity
Explain why the aerobic system has a high ATP yield.
Because glucose and fats are completely broken down in the presence of oxygen, producing large amounts of ATP.
How does protein contribute to energy production?
Only a small amount is used, mainly during prolonged or extreme exercise when glycogen/fats are low.
What is the main strategy to delay fatigue during endurance exercise?
Carbohydrate loading, pacing, and proper hydration
Explain why the ATP-CP system can only supply energy for a very short period.
Because CP stores are limited, and once depleted, ATP can no longer be rapidly resynthesized through this system.
Name one sporting example where anaerobic glycolysis is the predominant energy system.
400m sprint, 100m swim, gymnastics routine, 200m cycling sprint
Give two examples of endurance activities that rely on the aerobic system.
Marathon running, triathlon, long-distance cycling, swimming 800m+
Explain why fats are not used as the primary fuel for high-intensity exercise.
Because fat oxidation is slower and requires more oxygen, so ATP cannot be produced fast enough.
Explain why active recovery is better than passive recovery after intense exercise.
Active recovery helps remove lactate from the muscles faster, improves circulation, and speeds up recovery.