Physiological adaptations to endurance

Question 1

What are the 3 goals of aerobic endurance training?

Answer 1

1. increase VO2 max
2. increase lactate threshold (LT2)
3. improve efficiency/economy

Question 2

Why is VO2 max important for endurance performance?

Answer 2

• increased VO2max = increased aerobic performance capacity

- represents endurance exercise potential

Question 3

Why is the lactate threshold important for endurance performance?

Answer 3

• functional threshold of the highest power output/speed that can be maintained for any length of time
• high VO2 max with high LT2 = better performance

Question 4

Why is efficiency/economy important for endurance performance?

Answer 4

• work energy ratio
• oxygen consumed (VO2) : speed/power output
• improve technique by matching energy supply to demand

Question 5

What is the overall goal of aerobic endurance training?

Answer 5

Maximize the workload that can be maintained for a set distance or period of time without fatigue

Question 6

What are the main areas of adaptation in response to endurance training?

Answer 6

• Central: cardiovascular, pulmonary,
• Peripheral
• Lactate

Question 7

What are the 5 cardiovascular adaptations to endurance training? (list and describe)

Answer 7

Central:
1. Cardiac hypertrophy - eccentric hypertrophy
(left cavity), slight concentric hypertrophy (left walls)
2. Increased blood volume - increased plasma volume and haematocrit volume
3. Decreased in HR due to increased vagal dominance, increased parasympathetic and decreased sympathetic activity, decreased intrinsic firing rate of SA node
4. Increased stroke volume due to Left ventricular hypertrophy, bradycardia (increased diastole), decreased cardiac and arterial stiffness and increased contractility
5. Increased cardiac output due to increased SV

Question 8

What are the pulmonary adaptations to endurance training?

Answer 8

1. Increased tidal volume at rest and during sub-max and max loads
2. Decreased breath frequency
3. Increased strength and endurance of respiratory muscles
4. Metabolic adaptations in the respiratory muscles

Question 9

What are the 4 peripheral adaptations to endurance training?

Answer 9

1. Increased capillarisation - increased number of capillaries, increased surface area, slowed diffusion: due to increased VO2max
2. Metabolic changes: Increase in mitochondria size and number (increased aerobic capacity.), increase in oxidative enzymes (citrate synthase, malate dehydrogenase, succinate dehydrogenase), Increase fatty acid oxidation, increase utilisation of intramuscular triglycerides, decrease use of glucose stores
3. Muscular changes: Changes in fibre type characteristics (towards type I), shift to myosin ATPase (decreased ATP usage), hypertrophy of type I fibres, increased myoglobin concentrations.
4. a-VO2 difference improved

Question 10

What changes to lactate occur with endurance training? what happens to the HLa- curve? How does it affect performance?

Answer 10

Less creation and better clearance of lactate

• rightward shift in HLa- curve
• body can work at a higher intensity for a longer amount of time

Question 11

What are the effects of adaptations to endurance on goals of aerobic training? (what occurs to meet each goal)

Answer 11

1. increased VO2 max due to central and peripheral changes
2. increased lactate threshold due to peripheral changes
3. improvements in efficiency/economy mostly due to technique/skill and experience but possibly due to % of type I fibres, mitochondrial volume, limb stiffness and biomechanical factors

Question 12

What are the mean VO2 max values for males and females (trained and untrained)?

Answer 12

Male: 
- untrained = 35-45
- trained = 60-80
Female:
- untrained = 30-40
- trained = 60-70

Question 13

What are the mean lacate threshold LT2 values for trained and untrained?

Answer 13

Untrained = 65-70 % VO2 max 
Trained = 75-90 % VO2 max