Energy Transfer During Long Duration

Question 1

What system is used for long-duration?

Answer 1

Aerobic system

Question 2

What is oxygen consumption?

Answer 2

The amount of oxygen we use to produce ATP - referred to as VO2

Question 3

What happens when we start to exercise?

Answer 3

Insufficient oxygen is distributed to the tissues for all the energy to be provided aerobically, as it takes time for the body to respond to the increase in demand for oxygen.

As a result, energy is provided anaerobically to satisfy the increase in demand for energy until the body can cope (submaximal oxygen deficit).

Question 4

What is submaximal oxygen deficit?

Answer 4

When there is not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically.

Question 5

What is maximal oxygen deficit?

Answer 5

Usually referred to as maximal accumulated oxygen deficit or MAOD.

It gives an indication for anaerobic capacity.

Question 6

What is EPOC?

Answer 6

The amount of oxygen consumed during recovery above that which would have been consumed at rest during the same time.

Question 7

What does recovery involve?

Answer 7

Returning the body to its pre-existing state.

Question 8

Why does oxygen consumption remain high after exercise?

Answer 8

Extra oxygen needs to be taken in and used to try and help the performer recover.

Question 9

What are the two main components of EPOC?

Answer 9

The fast replenishment stage

The slow replenishment stage

Question 10

What is the fast replenishment stage?

Answer 10

The restoration of ATP and phosphocreatine stores and the re-saturation of myoglobin with oxygen.

Question 11

What happens during the fast replenishment stage?

Answer 11

It uses the extra oxygen taken in during recovery to restore and re-saturate.

Complete restoration of PC takes up to 3 minutes, but 50% of stores can be replenished after only 30 seconds, during which time approx 3L of oxygen are consumed.

Question 12

What happens to myoglobin during the fast replenishment stage?

Answer 12

It has a high affinity for oxygen.

It stores O2 in the sarcoplasm that has diffused from the haemoglobin in the blood.

After exercise, O2 stores in the myoglobin are limited.

The surplus of O2 supplied through EPOC helps replenish these stores, taking up to 2 minutes and using approx 0.5L of O2.

Question 13

What is the slow replenishment stage?

Answer 13

It’s also known as the lactic acid component - it has several functions:

Removal of lactic acid
Maintenance of breathing and heart rates
Glycogen replenishment
Increase in body temperature

Question 14

How can lactic acid be removed?

Answer 14

Oxidation into CO2 and water in the inactive muscles and organs and used by the muscles as an energy source

Transported in the blood to the liver where it is converted to blood glucose and glycogen (cori cycle)

Converted into protein

Removed in sweat and urine

Question 15

What is the cori cycle?

Answer 15

The process where lactic acid is transported in the blood to the liver where it is converted to blood glucose and glycogen.

Question 16

What happens to the majority of lactic acid?

Answer 16

It can be oxidised in mitochondria.

Question 17

What does a cool-down do? (Removal lactic acid).

Answer 17

Performing a cool-down can accelerate its removal because exercise keeps the metabolic rate of muscles high and keeps capillaries dilated, which means oxygen can be flushed through, removing the accumulated lactic acid.

Question 18

When does the slow replenishment stage of recovery begin?

Answer 18

As soon as lactic acid appears in the muscle cell, and will continue using breathed oxygen until recovery is complete.

This can take up to 5 or 6 litres of oxygen in the first half hour of recovery, removing up to 50% of the lactic acid.

Question 19

What is maintenance of breathing and heart rate?

Answer 19

Maintaining them require is extra oxygen to provide the energy needed for the respiratory and heart muscles.

This assist recovery as the extra oxygen is used to replenish ATP and PC stores, resaturate the myoglobin and remove lactic acid, therefore returning the body back to its pre-exercise state.

Question 20

What is glycogen replenishment?

Answer 20

The replacement of glycogen stores depends on the type of exercise undertaken and when and how much carbohydrate is consumed following exercise.

It may take several days to complete the restoration of glycogen after a marathon, but in less than an hour after high-duration, short-intensity exercise a significant amount of glycogen can be restored as lactic acid and is converted back to blood glucose and glycogen in the liver via the Cori cycle.

Eating a high-carbohydrate meal will accelerate glycogen restoration, as will eating within one hour following exercise.

Question 21

What is increase in body temperature?

Answer 21

When temperature remains high, respiratory rate will also remain high and this will help the performer take in more oxygen during recovery.

However, extra oxygen (from the slow replenishment stage) is needed to fuel this increase in temperature until the body returns to normal.