6.3. Aerobic Capacity Flashcards
What is aerobic capacity?
The ability to take in, transport and use oxygen to sustain prolonged periods of aerobic/sub maximal work
What is vo2 max?
The highest rate of o2 consumption attainable during maximal aerobic exercise.
What is a key indicator of aerobic endurance?
An ability to work at a high percentage of vo2 max
Average vo2 max for male
45-54 ml/kg/min
Average vo2 max for female
36-44 ml/kg/min
What are the factors affecting vo2 max?
- Individual physiological makeup -> respiratory system, cardiac system, vascular system, muscle cells
- Training
- Age
- Gender
How does individual physiological makeup affect vo2 max?
- Respiratory system: lung volumes increase, strength of respiratory muscles = increased lung volumes, number of alveoli, number of capillaries
- Cardiac system: ability to transport O2- heart hypertrophy, stroke volume
- Vascular system: ability to transport O2 - flexibility of vessels to perform vascular shunt, venous return mechanisms, blood volume, red blood cell count
- Muscle cells: to less O2- amount of myoglobin + capillaries, stores of fuel glycogen and fat to produce energy, increase mitochondria
How does training affect vo2?
A specific programme of aerobic training will increase vo2 max/ aerobic capacity due to the adaptations that take place
How does age affect vo2 max?
As we get older, our vo2 max declines as our body systems become less efficient -> approx 1% decline per year (10% per decade)
- CV system decline:
- Max HR decreases (6-10 BPM)
- Cardiac output/ SV/ blood transportation to muscle tissue decreases mainly due to weakening of contractions of left ventricle and elasticity of cardiac and vascular tissue
- Respiratory system declines:
- Decrease in maximum ventilation - both vital capacity and minute ventilation is reduced. This is due to the decrease in contractile strength of the respiratory muscles.
- Part of the decline is due to falling activity levels. Maintaining activity will slow physical degradation.
How does gender affect vo2 max?
Vo2 max values are generally 20-25% less for women than men
This is due to:
- Smaller body size -> smaller lung size
- Smaller left ventricle -> lower stroke volume and Q at max work rates
- Lower blood volume -> less haemoglobin (less o2 carrying capacity)
- Women are also disadvantaged by carrying a greater % of body fat - lowering their vo2 per kg of body mass
What are indirect or predictive tests?
These estimate or predict a vo2 max based on the results of the test.
What are direct tests?
These are accurate tests which directly measure the oxygen consumption and usage.
What is the Queen’s College Step Test?
- A continuous three minute step test which uses heart rate recovery to predict vo2 max
- Step to a metronome - men 24/ women 22 steps per min
- HR is recorded 5 secs after completion for 15 secs (then multiplied by 4 to get BPM)
Strengths of QCST
- Sub maximal test, safe for elderly, health conditions
- Standardised tables available to analyse results
- Minimal equipment needed and cheap
Weaknesses of QCST
- Only a predictive test, not a measurement
- Not specific to any sport
- May disadvantage shorter athletes
What is the multi stage fitness test?
- Indirect test
- It is a progressive maximal test
- Involves a 20m shuttle run
- 20m run is timed by a beep, which progressively becomes shorter after each level
- Test ends when the athlete fails to keep up with two successive beeps or drops out
- A level and shuttle number is recorded and compared with standardised results
Strengths of MSFT
- Suitable for large groups
- Minimal equipment needed and cheap
- Standardised tables available
Weaknesses of MSFT
- Exhaustive test- not suitable for elderly/ health conditions for elderly/ health conditions
- Only a predictive test not a measurement
- Less suitable for non-runners
What is the Cooper 12 minute run?
Continuous maximum intensity test measuring the maximum distance achieved around a 400m running track in 12 minutes to predict vo2 max
Strengths of Cooper 12 minute run
- Suitable for large groups
- Minimal equipment needed and cheap
- Standardised tables available to analyse results
Weaknesses of Cooper 12 minute run
- Exhaustive test- not suitable for elderly/ health conditions
- Only a predictive test not a measurement
- Less suitable for non-runners
What is direct gas analysis test
- A direct test measuring accurately vo2 max
- it is the most valid and accurate method.
- A progressive run/ cycle/ row test to exhaustion
- Performer wears a mask that measures the oxygen in the air breathed into the lungs comparing it to the measured oxygen being breathed out.
- The difference between the two figures is the consumed oxygen.
- When 02 levels in the expired air remain constant even when the intensity rises the test is complete. They will have reached VO2 max and will finish the test working anaerobically.
Strengths of direct gas analysis
- Accurate, valid, reliable measurement
- Can use bike, rower or treadmill so suits variety of athletes
Weaknesses of direct gas analysis test
- Expensive equipment - limited access
- Exhaustive test not safe for elderly/ healthy conditions
