Aerobic Fitness and Performance (year 2)

Question 1

What is Aerobic Fitness?

Answer 1

• The capacity to sustain a given speed or work rate
for the longest possible time

• For exercise longer than 120s, the majority of
energy is derived through oxidative metabolism

• Requires O2
to be delivered to the mitochondria,
sufficient availability of fuels and appropriate
oxidative capacity within the mitochondria

Question 2

What are the Parameters of Aerobic Fitness?

Answer 2

• Maximal Oxygen Uptake
• Maximum rate that the body can consume oxygen
• Running Economy
• How much oxygen it costs to run a certain speed
• The fractional utilization of maximal oxygen uptake
• Linked to the lactate accumulation in muscles and blood
• Oxygen Uptake kinetics
• The rate at which oxygen uptake rises when we start exercising

Question 3

what is Maximal Oxygen Uptake?

Answer 3

• Integrated capacity of pulmonary, cardiovascular and muscular systems
• Highest O2 uptake despite further increases in work rate/exercise intensity
• Reflects uptake, transport and utilisation of O2
• Criterion measure of:
• Intervention efficacy
• Environmental impact
• Disease prognosis

Question 4

Verifying a VO2 Max

Answer 4

• Leveling off in VO2 despite increasing work rate: <150 ml∙min–1 or <2.1 ml∙kg–1
∙min–1

• Secondary criteria:
• Post-exercise blood lactate >8 mmol∙L
–1
• R >1.15
• HR within 10 beats∙min–1 of age-predicted maximal HR
• RPE ≥ 18
• Should not expect participants to meet all criteria

Question 5

what are the determinants of VO2 Max?

Answer 5

Oxygen Utilisation–>Peak VO2=cardiac output (Q)(O2 Delivery)x aterio-venous O2 difference(O2 Extraction)

Question 6

Effects of Training on VO2 Max?

Answer 6

• 15-30% increase in VO2max with endurance training in adults

• Effect of resistance training less clear
• 3/17 studies in young adults show positive effect
• 6/9 in older adults in older adults show positive effect

• Effect of HIIT equal to, or greater than, endurance
training

Question 7

VO2 Max and Performance: Limited practical applicability?

Answer 7

• Can’t distinguish between performances – limited adaptability in elite athletes
• Can’t design optimal training programmes

Question 8

what is Lactate threshold:

Answer 8

• The point at which blood lactate concentration first begins to increase systematically and consistently
• Some labs use a blood lactate concentration of 2mmol·l-1 but direct identification of first breakpoint in lactate curve preferable
• Mechanisms of fatigue may differ above and below the lactate threshold

Question 9

Lactate Threshold and Performance:

Answer 9

• Typically 50-60% VO2max in healthy, untrained people, increased to ≥80% in trained people

• Higher relative exercise intensity can be sustained without the accumulation of blood lactate =
delayed onset of fatigue

• Strong predictor of endurance performance
• Applicable to design/optimisation of training

• Optimal intensity for improvements
in endurance fitness

Question 10

what are Oxygen Uptake Kinetics?

Answer 10

The rate at which oxygen uptake changes in response to a change in metabolic demand

• Requires coordination between the respiratory, cardiovascular and muscular systems

• Pulmonary VO2
reflects muscular VO2 to within ±10%

• The faster these kinetics, the less reliance on finite non-oxidative resources

• The faster these kinetics, the lower the oxygen deficit
• Response is dependent on exercise intensity

Question 11

Effect of Training on VO2 Kinetics?

Answer 11

• Highly sensitive to endurance training and HIIT
• Speeds the phase II time constant
• Decreases the slow component amplitude

Question 12

Potential Mechanisms for improved VO2 kinetics: Metabolism?

Answer 12

Central: Metabolism

More rapid increase in O2 extraction (Oxidative capacity, Muscle fibre type, Peripheral: muscular)

Speeded Phase 2

Question 13

Potential Mechanisms for improved VO2 kinetics: Nervous system?

Answer 13

central: Nervous system, faster response to altered state:

Enhanced bulk O2 delivery (Central : cardiovascular)

Speeded Phase 2

Question 14

what is Exercise Economy?

Answer 14

• Oxygen cost of a given exercise intensity or speed

• High VO2max is important, but cannot discriminate
performance capability in athletes with similarly high values

• Exercise economy may explain the difference
• Good economy can compensate for relatively low VO2 max values in elite athletes

Question 15

Aerobic performance is comprised of 3 things?

Answer 15

Aerobic contribution,

rate of aerobic energy expenditure,

Exercise economy

all of the 3 are interrelated

Question 16

Aerobic performance: Rate of Aerobic energy expenditure is comprised of 3 parts, what are they?

Answer 16

VO2 Kinetics (also related to aerobic contributions),

VO2 max (VO2 max and VO2 Kinetics are interrelated),

Fractional utilisation (%VO2 max)