Muscle energetics

Question 1

What is the % of energy actually used for moving?

Answer 1

25% moving

75% heat

Question 2

What happens when you have a high ATP:ADP ratio?

Answer 2

Signals are sent to the body to produce more ATP

Question 3

What does the energy continuum contain? (3)

Answer 3

PCr (Phosphocreatine)
Glycolytic
Aerobic

Question 4

What is the order of entry continuum over time? (3)

Answer 4

1. At start PCr is immediate and others are slow to start
2. Glycolytic then peaks as PCr declines, aerobic slowly inclines
3. PCr decreases, Glycolytic decreases and aerobic increases

Question 5

What does PCr produce and what is its drawback? (2)

Answer 5

Produces inorganic phosphate - allosteric inactivator

Poisonous and can cause tumours, cell death etc

Question 6

What happens at high intensity exercise? (3)

Answer 6

• All fibres recruited
• 1-2 minutes
• Mostly PCr and Glycolytic

Question 7

How is PCr replenished? (equation)

Answer 7

ADP + PCr ATP + Cr

Question 8

What is the relationship between PCr and glycolysis?

Answer 8

PCr acts as a buffer for the lag of glycolysis

Question 9

What happens as muscle glycogen decreases?

Answer 9

Muscle lactate increases

Question 10

How long can we maintain intense exercise for with muscle glycogen?

Answer 10

90 minutes

Question 11

What is a high blood lactate level?

Answer 11

12-25mmol/KG

Question 12

How long can we rely on PCr and how long does it take to recover?

Answer 12

PCr: 1-2 minutes

2-3 minute rest to do further activity - HIE trainers must have large rests

Question 13

What happens initially when HIE occurs in terms of O2 value?

Answer 13

Initially, an oxygen deficit occurs

Lag between O2 demand and supply

Question 14

How does the body work with an oxygen deficit and what is the drawback of it?

Answer 14

ADP + ADP —> ATP + AMP
AMP is produced
Drawback: ammonia levels in blood stream increase

Question 15

How is exercise hormonally regulated? (2)

Answer 15

ADP release - slightly less energy is being used

AMP release - energy being used fast and need more energy

Question 16

What is phopshofructosekinase? (PFK)

Answer 16

Rate limiting enzyme in glycolysis (ATP –> ADP)

Question 17

What is an example of positive feedback in glycolysis?

Answer 17

AMP and ADP - need to increase

Question 18

What is an example of negative feedback in glycolysis?

Answer 18

ATP and PCr - regulate energy production

Question 19

What is the aerobic:anaerobic ratio in a marathon?

Answer 19

95:5 (hills/gradients and at the end)

Question 20

What are the energy sources used at different running distances? (3)

Answer 20

100m: PCr
200m - 800m: anaerobic glycolysis
800m - marathon: aerobic metabolism

Question 21

What are the fuels used at the initial stages of exercise? (3)

Answer 21

Fat:carbs are equal
Fat derived from free fatty acids and triglycerides
Glycogen provides carbs

Question 22

What fuels are used as exercise continues over a period? (2)

Answer 22

Decline in muscle glycogen stores - blood glucose becomes important
Plasma FFAs become more important

Question 23

Over 240 minutes, what is the trend shown by phosphate dehydrogenase kinase and pyruvate dehydrogenase kinase?

Answer 23

Phosphate dehydrogenase kinase: Gradual increase

Pyruvate dehydrogenase kinase: Gradual increase to 120 then decline

Question 24

What is muscle glycogen proportional to?

Answer 24

Performance

Question 25

What is the best exercise intensity to lose fat?

Answer 25

65%

Question 26

What takes longer to synthesise: fatty acids or carbs?

Answer 26

Fatty acids