vo2 max- max oxygen uptake

Question 1

vo2 used as a measure for aerobic capacity

Answer 1

why?
shows volume/ time of o2 that can be consumed
many systems used to be able to transport o2 efficiently

Question 2

fick equation

Answer 2

VO2=HRxSV x a-v difference
cant change max HR but can change SV which can increase cardiac output

Question 3

vo2 max + limiting factors

Answer 3

depends on
- good CV system and high cardiac output
- well developed oxidative capacity in skeletal muscle (mitochondria, oxidative enzymes)
limited by o2 delivery and o2 utlisation
vo2 max limited by stroke volume

Question 4

evidence- acute exercise

Answer 4

isolated muscle can use more o2 than the heart delivers
maximal 1 vs 2 legged exercise- max o2 extraction by quadriceps during 1 legged exercise is 2-3 times higher than measured in same muscle group during 2 legged exercise

Question 5

evidence- longitudinal

Answer 5

2.2 fold increase in mitochondrial enzymes but only 20-40% increase in vo2 max, individuals with similar vo2 max exhibit 2 fold range of mitochondrial enzymes
cardiac system is limiting muscle power/growth

Question 6

manipulation of blood volume

Answer 6

reducing blood volume through phlebotomy after training (to pre training levels) reduced both cardiac output and vo2 max to pre training levels

Question 7

expressing vo2 max

Answer 7

absolute score= 2.5l/min
female (50kg, 25yo)= 2.5/50= 50ml/kg/min
male (85kg, 35yo)= 29.4ml/kg/min

Question 8

age and training

Answer 8

after age of 25- 1% decrease per year
during ageing will be a more rapid decline

Question 9

hereditry

Answer 9

genetics accounts for 20-25% of variance in vo2 max between different people
typical world class runner= 85ml/kg/min

Question 10

protocol design to determine vo2 max

Answer 10

incremental exercose test to exhaustion
vo2 max- aim for protocols where exhaustion is achieved within 8-12 mins
too short= exhaustion due to peripheral limitations
too long= exhasution due to duration
use large muscle groups( cycling, running, rowing) that stressed max cardiac output + avoids premature local muscle failure

Question 11

maximal o2 uptake

Answer 11

primary criteria- plateau in vo2 max despite increasing load or increasing speed to next stage
only found in 40-45% of people
secondary criteria
HR within 90% of age predicted max
BL conc over 8mmol
RER of 1.15 or above
RPE>19
vo2 peak indicated peak o2 uptake reached in specific test

Question 12

determinants of endurance performance

Answer 12

ability to use o2 is the main physiological determinant of endurance performance (vo2 max)
abiloty to sustain high % of vo2 max over the time of the race- high lactate threshold, high lactate steady state
ability to produce high power/speed at a given o2 uptake (economy/technique)