aerobic capacity
the ability of the body to inspire, transport + utilise oxygen to perform sustained periods of aerobic activity
VO2 max
maximum volume of oxygen inspired, transported and utilised per minute during exhaustive exercise
factors affecting VO2 max
- individual physiological makeup
- age
- gender
- training
VO2 max - physiological makeup
the greater the efficiency of: - respiratory system - cardiovascular system - muscle cells to inspire, transport + utilise O2 = the higher the VO2 max
VO2 max - age
from the early 20’s, VO2 max declines approx 1% every year
VO2 max - gender
females tend to have a 15-30% lower VO2 max than males from the same group
VO2 max - training
aerobic training will increase VO2 max by 10-20%
in ageing performers, aerobic training will maintain or reduce any decline in VO2 max
methods of evaluating aerobic capacity
- laboratory test of VO2 max using direct gas analysis
- NCF multi-stage fitness test
- Queen’s College step test
- Cooper 12 minute run
VO2 max - direct gas analysis
- subject performs continuous exercise at progressive intensities to exhaustion
- expired air is captured by a mask connected to a gas analyser
- relative concentrations of O2 + CO2 in expired air to inspired air are measured
- results are graphed + VO2 calculated = simple calculation
ads + disads of direct gas analysis
+ direct objective measurement of VO2max
+ accurate, valid and reliable measure
- maximal test to exhaustion so depends on subject’s motivation
- cannot be used with the elderly or those with health conditions
- access to specialist equipment is required
VO2 max - Cooper 12-minute run
- subject performs continuous running to achieve a max distance within 12 mins
- performed on a 400m track w/ cones placed at intervals
- max-intensity test which uses simple calculation to predict VO2 max
ads + disads of Cooper 12-minute run
+ large groups can perform the test at the same time in a field-based setting
+ simple and cheap equipment required
+ subject can self administer their own test
+ published tables of normative data
+ simple VO2 max calculation
- prediction of VO2 max, not actual measurement
- test is not sport specific
- cannot be used with elders or those with health conditions
- maximal test to exhaustion so limited by subject motivation
VO2 max - Queen’s College step test
- subject performs continuous stepping on and off a box 41.3cm high for a period of 3 mins
- steps taken at a rate of 24 steps/min = men, 22 steps/min = women
- HR is taken 5 secs after completing the test for 15 secs
- Hr recovery is used to predict VO2 max w/ a simple equation
ads + disads of Queen’s college step test
+ simple and cheap equipment required
+ sub-maximal test
+ simple VO2 max calculation
+ published tables of normative data
- prediction of VO2 max not a measurement
- step height may disadvantage shorter subjects
- test is not sport specific
VO2 max - NCF multi-stage fitness test
- subject performs a continuous 20m shuttle run test at progressive intensities to exhaustion
- each shuttle run will be timed to an audio cue
- test is over when the subject cannot complete the shuttle in the allotted time
- a level + shuttle number given to predict Vo2 max from a standardised comparison table
ads + disads of NCF multi-stage fitness test
+ only simple and cheap equipment required
+ large groups can perform the test at the same time
- only a prediction of VO2 max not a measurement
- maximal test to exhaustion so limited to subject’s motivation
- test is not sport specific e.g. cyclists or rowers may be at a disadvantage
- cannot be used with the elderly or those with health conditions
which training methods develop aerobic capacity?
- continuous training
- high intensity interval training (HIIT)
continuous training
steady-state low-moderate intensity work for a prolonged period of time
intensity = 60-80% of HR duration = 20-80 mins
HIIT training
repeated bouts of high intensity work followed by varied recovery times
work intervals:
intensity = 80-95% of HR
duration = 5 seconds to 8 mins
rest intervals:
intensity = 40-50% of HR
duration: equal to the work interval (1:! work to relief ratio)
use of target heart rates as an intensity guide
HR max = 220 - age
training zone = resting HR + % (HR max - resting HR)
basic endurance - very light = 50-60%
targets fat burning - light = 60-70%
aerobic zone - moderate = 70-80%
lactate threshold - hard = 80-90%
max performance capacity - max = 90-100%
physiological adaptations from aerobic training
- cardiovascular
- respiratory
- muscular
- metabolic
cardiovascular adaptations from aerobic training
- cardiac hypertrophy = increased SV at rest + exercise, increased CO at rest –> also bradycardia/ decreased resting HR at rest + HR recovery after exercise
- increased no. of red blood cells/ haemoglobin content = increase in o2 carrying capacity –> increased gaseous exchange
- increased blood/ plasma volume = lower blood viscosity - aids venous return + blood flow
- overall increased blood flow + o2 transport to muscle cells
- overall decreased BP
- lower risk of coronary heart disease, hypertension, stroke
- easier to perform exercise + reduce the onset of fatigue
respiratory adaptations from aerobic training
- stronger respiratory muscles = increased mechanics of breathing efficiency
- increased surface area of alveoli = increased external gaseous exchange = increased external gaseous exchange
overall:
- increased volume of o2 diffused into blood stream
- makes it easier to perform exercise = reduce the onset of fatigue
- alleviates the symptoms of asthma
muscular adaptations from aerobic training
- slow oxidative muscle fibre hypertrophy
- FINISH
