Podcast
Questions and Answers
Which of the following accurately describes the role and speed of the phosphagen system in providing energy for muscle activity?
Which of the following accurately describes the role and speed of the phosphagen system in providing energy for muscle activity?
- It provides ATP aerobically and is four times as fast as the oxidative system.
- It provides ATP anaerobically and is roughly twice as fast as the glycolytic system. (correct)
- It provides ATP aerobically and is the slowest energy system.
- It provides ATP anaerobically and is slower than both the glycolytic and oxidative systems.
During a high-intensity exercise lasting 10 seconds, which energy system is predominantly used to supply ATP?
During a high-intensity exercise lasting 10 seconds, which energy system is predominantly used to supply ATP?
- Glycolytic system
- Fatty acid oxidation
- Oxidative system
- Phosphagen system (correct)
What is the approximate amount of ATP stored in the body under normal resting conditions, and why is it maintained in small amounts?
What is the approximate amount of ATP stored in the body under normal resting conditions, and why is it maintained in small amounts?
- 1000 to 1200 g, to ensure sufficient energy is always available for high-intensity activities.
- 500 to 700 g, to provide a stable energy reserve during prolonged periods of fasting.
- 80 to 100 g, so its relative concentration changes rapidly in response to a minimal ATP decrease. (correct)
- 200 to 300 g, to allow for constant energy expenditure during low-intensity activities.
How does phosphocreatine (PCr) contribute to ATP resynthesis during muscle activity?
How does phosphocreatine (PCr) contribute to ATP resynthesis during muscle activity?
Which statement accurately describes the energy derived from phosphocreatine (PCr)?
Which statement accurately describes the energy derived from phosphocreatine (PCr)?
In the context of coupled reactions within the phosphagen system, which of the following best describes the roles of exergonic and endergonic reactions?
In the context of coupled reactions within the phosphagen system, which of the following best describes the roles of exergonic and endergonic reactions?
Creatine kinase (CK) is a reversible reaction, what determines the direction of the reaction?
Creatine kinase (CK) is a reversible reaction, what determines the direction of the reaction?
How does creatine kinase (CK) function differently during high-intensity activity versus recovery from exercise?
How does creatine kinase (CK) function differently during high-intensity activity versus recovery from exercise?
During high-intensity exercise, what primarily dictates the direction of the creatine kinase (CK) reaction?
During high-intensity exercise, what primarily dictates the direction of the creatine kinase (CK) reaction?
Why is the phosphagen system the predominant energy source at the onset of exercise and during very high-intensity activities?
Why is the phosphagen system the predominant energy source at the onset of exercise and during very high-intensity activities?
How would increasing muscle creatine (Cr) levels through supplementation potentially aid in phosphocreatine (PCr) recovery following high-intensity exercise?
How would increasing muscle creatine (Cr) levels through supplementation potentially aid in phosphocreatine (PCr) recovery following high-intensity exercise?
Following intense exercise, what is the correct sequence of events for phosphagen recovery?
Following intense exercise, what is the correct sequence of events for phosphagen recovery?
Why is training considered the most effective method for improving the phosphagen system, compared to creatine supplementation alone?
Why is training considered the most effective method for improving the phosphagen system, compared to creatine supplementation alone?
A power athlete is considering creatine supplementation. Which of the following statements best describes the expected outcome based on the mass action effect?
A power athlete is considering creatine supplementation. Which of the following statements best describes the expected outcome based on the mass action effect?
If an athlete performs a maximal intensity sprint, approximately how long will the phosphagen system be able to sustain ATP production before phosphocreatine (PCr) stores are significantly depleted?
If an athlete performs a maximal intensity sprint, approximately how long will the phosphagen system be able to sustain ATP production before phosphocreatine (PCr) stores are significantly depleted?
Following a high-intensity exercise bout that significantly depletes phosphocreatine (PCr) stores, approximately how long does it take for PCr to be fully restored in the muscle?
Following a high-intensity exercise bout that significantly depletes phosphocreatine (PCr) stores, approximately how long does it take for PCr to be fully restored in the muscle?
Flashcards
Phosphagen System
Phosphagen System
Provides ATP anaerobically and is the fastest energy system. Fuels maximal intensity activity for up to 12-15 seconds.
Stored ATP
Stored ATP
A small quantity of ATP stored in cells, that is continually resynthesized at its rate of use.
Phosphocreatine (PCr)
Phosphocreatine (PCr)
Cells store 4-6x more PCr than ATP. PCr rapidly provides ATP in the presence of ADP.
PCr Energy Use
PCr Energy Use
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Creatine Kinase (CK)
Creatine Kinase (CK)
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ATP Storage
ATP Storage
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Phosphocreatine (PCr)
Phosphocreatine (PCr)
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Coupled Reaction
Coupled Reaction
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Duration of Phosphagen System
Duration of Phosphagen System
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ATP Recovery
ATP Recovery
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PCr Restoration
PCr Restoration
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ATP Recovery Time
ATP Recovery Time
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PCr Recovery Time
PCr Recovery Time
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Creatine Supplementation Benefit
Creatine Supplementation Benefit
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Study Notes
- The phosphagen system provides ATP anaerobically, and is the fastest energy system.
- It is roughly twice as fast as the glycolytic system and four times as fast as the oxidative system in providing ATP.
- It fuels maximal intensity activity for up to 12-15 seconds.
- The phosphagen system consists of stored ATP and phosphocreatine stores.
Stored ATP
- Cells contain a small quantity of ATP, so they must continually resynthesize it at its rate of use.
- The body stores only 80 to 100 g of ATP at any time under normal resting conditions.
- Maintaining small amounts leads to rapid changes in relative concentration in response to a minimal ATP decrease.
- ATP lasts only 3-5 seconds at maximal intensity.
Phosphocreatine
- PCr is also called creatinephosphate (CP).
- Cells store approximately 4-6 times more PCr than ATP.
- PCr rapidly provides ATP in the presence of ADP.
- Energy for ATP resynthesis comes from the anaerobic splitting of a phosphate from PCr.
- Energy for ATP resynthesis is derived from the anaerobic splitting of a phosphate from PCr.
- PCr energy cannot be used for cellular work; it reassembles ATP.
- The PCr reaction is a coupled reaction, including both exergonic and endergonic reactions.
- Creatine kinase (CK) is a reversible reaction.
- CK generates ATP during high-intensity activity and regenerates PCr during recovery from exercise.
- The direction of the reaction depends on the energy need, directed by the Mass Action Effect.
- PCr provides ATP during maximal intensity exercise until PCr is depleted in about 3-12 seconds of maximal exercise.
- The maximum energy yield is reached in about 10 seconds.
Recovery for Phosphagens
- ATP recovery uses oxidative phosphorylation in the electron transport chain (ETC) via the enzyme ATP synthase, taking 3-5 minutes.
- PCr is restored using ATP as a substrate in the creatine kinase reaction, taking 8-10 minutes.
- Stored ATP must be recovered first.
Creatine Supplementation
- Recovery takes 8-10 minutes.
- Stored ATP must be recovered first.
- Creatine supplementation increases muscle [Cr], but not [PCr].
- Based on the Mass Action Effect, creatine supplementation helps recover PCr more quickly.
- Supplements can help, but the best way to improve the phosphagen system is through training.
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Description
The phosphagen system is the fastest anaerobic energy system, fueling maximal intensity activity for 12-15 seconds. It consists of stored ATP, lasting 3-5 seconds, and phosphocreatine (PCr), which cells store in 4-6 times greater quantities than ATP. PCr rapidly provides ATP in the presence of ADP.
