Unit 3 Aos 2 P.E energy systems and nutrition

help

What is oxygen deficit?

The period at the start of exercise when oxygen demand exceeds oxygen supply, so the body cannot meet its energy demands aerobically.

What is steady state?

When oxygen supply meets oxygen demand and heart rate plateaus, allowing aerobic ATP production to meet energy needs.

What is excess post-exercise oxygen consumption (EPOC)?

The period after exercise where oxygen consumption remains elevated to restore the body to pre-exercise levels (e.g. replenish CP, remove by-products, restore oxygen stores).

What is VO₂ max?

The maximum amount of oxygen the body can take in, transport, and use per minute during maximal exercise.

What happens to heart rate during exercise? - Cardiovascular Response

Increases to pump more blood and deliver more oxygen to working muscles.

What is stroke volume? (SV) - Cardiovascular Response

The amount of blood ejected from the left ventricle per beat. increases

What is cardiac output? (Q) - Cardiovascular Response

The amount of blood pumped by the heart per minute. increases
Q = HR × SV

What happens to blood pressure during exercise?

Systolic blood pressure increases due to increased cardiac output; diastolic remains relatively stable.

What happens to blood volume during exercise?- Cardiovascular Response

Decreases due to plasma loss through sweating.

What is venous return?- Cardiovascular Response

The return of blood to the heart; increases during exercise to match increased cardiac output.

What is blood redistribution? - Cardiovascular Response

Blood is redirected from non-essential areas to working muscles.

What happens to respiratory rate during exercise? (RR) - Respiratory response

Increases to allow more oxygen into the lungs.

What is tidal volume? (TV) - Respiratory response

The amount of air inhaled and exhaled per breath. increases

What is ventilation? (V) - Respiratory response

The amount of air inhaled and exhaled per minute.
V = TV × RR increases

What is pulmonary diffusion? - Respiratory response

The exchange of gases (O₂ and carbon dioxide) between the lungs and blood; increases during exercise.

What happens to motor unit recruitment during exercise? - Muscular responses

Increases to produce greater force

What happens to muscle temperature? - Muscular responses

Increases due to energy production, improving muscle efficiency.

What happens to by-products during exercise? - Muscular responses

Increase, especially hydrogen ions (H⁺), contributing to fatigue.

What is energy substrate depletion? - Muscular responses

The reduction of fuels (ATP, CP, glycogen) as they are used faster than they can be replenished.

ATP-PC system characteristics

• Fuel: Creatine phosphate (CP)

• Rate of ATP production: VERY FAST

• Yield of ATP: VERY LOW (1 ATP per CP)

• Duration: 0–10 seconds

• By-products: None

• Recovery: Passive

Anaerobic glycolysis characteristics

• Fuel: Glucose/glycogen (carbohydrates)

• Rate of ATP production: FAST

• Yield of ATP: LOW–MODERATE (2–3 ATP per glucose)

• Duration: ~10–75 seconds

• By-products: Hydrogen ions (H⁺)

• Recovery: Active

Aerobic system characteristics

• Fuel: Carbohydrates, fats, proteins

• Rate of ATP production: SLOW

• Yield of ATP: VERY HIGH (~36–38 ATP per glucose)

• Duration: Long duration (2+ minutes)

• By-products: Carbon dioxide + water

• Recovery: Active

What is passive recovery?

Complete rest; best for restoring ATP-PC stores.

What is active recovery?

Low-intensity exercise to remove by-products and prevent venous pooling.

What is fuel depletion?

When energy stores (ATP, CP, glycogen) are used up, reducing performance.

What is accumulation of metabolic by-products?

Build-up of substances like H⁺ that reduce muscle function and cause fatigue.

Causes of fatigue in each system

• ATP-PC: Fuel depletion (CP)

• Anaerobic glycolysis: H⁺ accumulation

• Aerobic: Glycogen depletion + dehydration

Why is hydration important for performance?

• Maintains blood plasma volume

• Supports thermoregulation (cooling via sweat)

• Maintains cardiovascular function (HR + stroke volume)

• Delays fatigue caused by dehydration

When should water vs sports drinks be used?

• Water: Short duration, low intensity exercise

• Sports drinks: Long duration/high intensity exercise (60+ mins)

Why are sports drinks beneficial?

• Replace electrolytes (sodium, potassium) lost in sweat

• Help maintain nerve and muscle function

• Provide carbohydrates for ATP resynthesis

• Improve fluid absorption

What are electrolytes and why are they important?

• Minerals (e.g. sodium, potassium) lost in sweat

• Help maintain fluid balance

• Essential for muscle contraction and nerve impulses

Why are carbohydrates important for performance?

• Primary fuel source for ATP production

• Stored as glycogen in muscles and liver

• Essential for both aerobic and anaerobic systems

What is glycogen depletion?

• Depletion of carbohydrate stores

• Leads to fatigue and reduced performance

Why is carbohydrate replenishment important?

• Restores glycogen stores

• Speeds up recovery

• Allows repeated performance

When should carbohydrates be consumed post-exercise?

• Within 30–60 minutes (glycogen window)

• Faster glycogen resynthesis occurs immediately after exercise

---

What is carbohydrate loading?

• High carbohydrate diet 2–3 days before endurance events

• Maximises glycogen stores

• Delays fatigue in long-duration events

Why is protein important for athletes?

• Muscle repair and recovery

• Supports muscle growth

• Helps adapt to training

When should protein be consumed?

• After exercise

• Often combined with carbohydrates for better recovery

How do nutrition and hydration support recovery?
Back:

• enish glycogen (aerobic system)

• Restore fluids and blood plasma

• Remove by-products via improved circulation

• Prepare body for next performance

What energy system is predominantly used in this prac?

• ATP-PC system (dominant)

• Some contribution from anaerobic glycolysis in later sprints as CP depletes

What fuel is used in the phosphate recovery test?

• Creatine phosphate (CP)

• Small amount of glycogen in later efforts

What happens to performance across the 8 sprints?

• Distance/cones reached decreases over time

• Due to incomplete CP resynthesis and fatigue

What type of recovery is used in the prac and why?

• Passive recovery (standing/walking back)

• Best for CP resynthesis

What happens during the prac recovery?

• CP stores are partially replenished

• Requires oxygen (aerobic system)

• Not fully restored in 25 seconds → performance declines

How do energy systems interact in this prac test?

• ATP-PC dominant at start

• Anaerobic glycolysis increases as CP depletes

• Aerobic system helps recovery (CP resynthesis)