Requirements for Work

Question 1

Describe muscle metabolism

Answer 1

• unique ability - external work
• contraction requires ATP as an immediate energy source
• ATP must be rapidly and continuously regenerated during contraction
• ATP requirements may increase by 40-50 times during heavy excercise

Question 2

Describe phase I or short term ATP

Answer 2

• short term, ATP comes from anaerobic sources
• allows for immediate, rapid ATP regeneration at onset of exercise (short and long term)
• sole or predominant source of ATP during short-term, explosive activity

Relies on two readily available sources of energy already stored in muscle
1. creatine phosphate
2. glycolysis (anaerobic)

Question 3

Describe phase II or longer term ATP

Answer 3

Longer term generation of ATP occurs via oxidation of glucose and fatty acids

Glucose sources are
1. muscle glycogen
2. blood glucose

Fatty acid sources are blood non-esterified fatty acids (NEFA) mobilized from adipose tissue

Rate of ATP synthesis from these sources in limited by the rate of oxygen delivery to the contracting muscle

Question 4

What is VO2 max?

Answer 4

maximum oxygen uptake or aerobic capacity

expected to be higher for higher working animals, ex. athletes

Question 5

What are the sources of energy for short term ATP production?

Answer 5

creatine phosphate and glycolysis

Question 6

What are the sources of energy and glucose for long term ATP production?

Answer 6

energy from oxidation of glucose and fatty acids

glucose from muscle glycogen and blood glucose

Question 7

How is ATP synthesis limited in the long term?

Answer 7

It is limited by the amount of O2 delivery