Week 4 Energy Systems

Question 1

What does aerobic training lead to

Answer 1

Improved blood flow and increased capacity of muscle fibres to generate ATP

Question 2

What does anaerobic training lead to

Answer 2

Increased muscular strength and increased tolerance for acid-base imbalances during high intensity effort

Question 3

Define undertraining, acute overload, overreaching and overtraining in regards to training

Answer 3

Under training - minor physiological changes but no change in performance
Acute overload - positive physiological changes and minor improvements in performance
Overreaching - optimal physiological changes and performance
Overtraining - Too much

Question 4

Muscle adaptations that occur due to aerobic training (5)

Answer 4

1. Increased area of ST fibres
2. Small # of fibres change from FTX to FTA fibres
3. Increased number of capillaries supplying the muscles (increase in VO2 max)
4. Increased myogoblin content in muscle (increased muscle storage of O2)
5. Increased number, size and enzyme activity of mitochodria

Question 5

Energy source adaptations that occur due to aerobic training (4)

Answer 5

1. Trained muscles store more glycogen and triglycerides
2. FFAs are better mobilized and more accessible
3. Muscles ability to oxidise fat increases
4. Muscles increase reliance on fat stores so glycogen can be spared

Question 6

What is VO2max and QO2

Answer 6

VO2 max measures bodies maximal oxygen uptake

QO2 measures the maximal respiratory/oxidative capacity of a muscle.

Question 7

What changes occur to the lactate threshold due to aerobic training?

Answer 7

Lactate threshold increases, untrained muscle is at 55% VO2 max, trained muscle is at 77%.

Question 8

What are the adaptations to anaerobic training (6)

Answer 8

1. Increased muscular strength
2. Increased ATP-PCr and glycolytic enzymes
3. Improved mechanical efficiency
4. Increased muscle oxidative capacity
5. Increased muscle buffering capacity
6. Changes in muscle fibres I -> IIa -> IIx

Question 9

What is the benefit of improved muscle buffering capacity?

Answer 9

Allows sprint trained athletes to generate energy for longer periods before fatigue limits (only occurs due to anaerobic training).

Question 10

What is direct calorimetry

Answer 10

Measures heat production to calculate energy expenditure. Unless mechanical work is done, all energy extracted from food ends up as heat

Question 11

What is indirect calorimetry

Answer 11

Measurement of oxygen consumption as an estimate of resting metabolic rate
Calculates energy expenditure from the respiratory exchange ratio of VCO2 and VO2
Requires a steady state and takes into account mechanical work done.

Question 12

What is the respiratory exchange ratio (RER)

Answer 12

The ratio between CO2 released (VCO2) divided by oxygen consumed (VO2). The RER at rest is usually 0.78-0.8.

Question 13

What are the RER values for CHO and fat and how is this found

Answer 13

CHO = 1
Fat = 0.7
Carbohydrates: 1 molecule of CO2 produced for each mole of O2 used, 3.1 ATP molecules produced for each atom of oxygen used
Fats: 0.7 moles of CO2 produced for each mole of O2 used. 2.8 ATP generated for each atom of oxygen used.

Question 14

Describe how a direct (bomb) calorimetry is used

Answer 14

The sample is placed into a chamber of O2 and is surrounded by water. The chamber is then heated up and using a thermometer and stirrer, seeing how hot the water gets before the sample is depleted.

Question 15

Describe how a indirect calorimetry is used

Answer 15

Expired gas are collected in an air tight bag, the gas is measured for temperature and density and then using that can calculate VO2

Question 16

Whats an ideal aerobic training volume regarding energy expenditure

Answer 16

5000-6000 kcal per week