Adaptations to endurance exercise Flashcards
How much are changes to VO2 max attributed to genetic factors?
How much is maternal heritability and why?
~47%
~28% due to maternal heritability as we inherit our mitochondria from our mother
- (Bouchard et al, 1999)
Define O2 deficit
the difference between O2 requirement and O2 uptake at the onset of exercise.
- (Burnley & Jones, 2007)
Why does an O2 deficit occur?
Upon beginning of exercise, your body requires a set amount of oxygen. Your body can’t keep up with the demands straight away and gradually increases O2 uptake.
What is the time constant of the VO2 response?
1/4 of the time taken to reach steady state of oxygen uptake
What are the implications of a reduced time constant of VO2 response?
less O2 deficit, therefore…
less reliance on anaerobic energy systems, therefore…
> less PCr depletion
less glycogen depletion
blunt the increase in metabolites associated with fatigue
- (Burnley & Jones, 2007)
What determines VO2 kinetics?
training status
trained cyclists reach steady state quicker (reduced time constant) than untrained cyclists in multiple power output conditions
- (Koppo et al, 2004)
What effect does endurance exercise have on…
- time constant of VO2 response
- O2 deficit
- VO2 max
- reduces
- reduces
- improves
What 2 processes can the physiological adaptations associated with endurance exercise be split in to?
- O2 delivery (central aspects)
2. O2 delivery (peripheral aspects)
Do the lungs adapt to (get larger from) running or rowing?
no,
large lung capacities in these sports are seen likely as a result of genetic endowment
do the lungs adapt to (get larger from) swimming?
you bet your ass they do,
a progressive swimming programme for competitive female college swimmers over 10 weeks was shown to…
>increase vital capacity
>increase total lung capacity
- (Clanton et al, 1987)
What effect does running training have on respiratory muscles?
. no change to maximum inspiratory pressure (strength)
. 16% increase to maximum sustainable ventilatory capacity (endurance)
- (Robinson & Kjeldgaard, 1982)
What effect does swimming training have on respiratory muscles?
. 17% increase to maximum inspiratory pressure (strength)
. 113% increase to time @ 65% MIP (endurance)
- (Clanton et al, 1987)
Are we able to effectively compare the effects of running and swimming training on inspiratory muscle endurance from the studies of Robinson & Kjeldgaard,
(1982) and Clanton et al (1987) ?
No,
they used different measures to assess inspiratory muscle endurance
True or false…
haemoglobin saturation and concentration (per L of blood) significantly increase with endurance training
False,
no changes to saturation
only slight increase in concentration
What is the effect of endurance training on total haemoglobin mass and why does this change occur?
Total haemoglobin mass increases, due to rises in blood volume with endurance training.
What effect does endurance training have on heart rate at any given intensity (O2 uptake)?
HR is lower is at any given O2 uptake
- (Saltin, 1969)
Does Stroke volume change with endurance training?
yes,
increases for any given oxygen uptake
- (Saltin, 1969)
What causes the increase to cardiac output with training?
Increases to SV, as HR drops
What causes the increase in stroke volume with endurance exercise?
> increased blood plasma volume (short term)
> cardiac hypertrophy (long term)
What effect does increasing plasma volume by 200-300 mL via infusion have on VO2 max?
5percenters
Increases it by roughly 5%
What is the overall effect of all of these adaptations to O2 delivery?
Increased maximal delivery of O2 to periphery
What effect does training have on capillary density, and by what process do these changes occur?
training = increased capillary density (2-3 x more capillaries per muscle fibre)
occurs due to angiogenesis which takes one of two forms…
> sprouting - new vessel sprouts from another
> intussusception - one vessel split in two
- (Prior et al, 2004)
True or false…
endurance training increases the size AND number of mitochondria
True
How is citrate synthase activity influenced by activity?
it is proportional to the number of muscle contraction an individual makes.
Immobilised (x0.7)
moderate training (x1.5)
elite training (x3)
What are 3 consequences of the mitochondrial adaptations as a response to endurance exercise?
- mitochondria are closer to intramuscular triglycerides (more CSA touching)
as a result… - increased fat metabolism during exercise
as a result… - less depletion of glycogen stores during activity
What effect does training have on the formation of lactate?
increased mitochondria = decreased accumulation of pyruvate
What effect does training have on the removal of lactate?
better maintenance of blood flow to the kidneys and liver = greater removal of lactate
What effect does a higher lactate threshold have on endurance performance?
you’re able to work for longer at a higher percentage of VO2 max
What is a-vO2 diff?
arteriovenous O2 difference
the difference in O2 content of the arterial and venous blood.
gives an indication of much much oxygen is removed from the blood as it circulates through the body
What is the effect of detraining on VO2 max?
rapid decline, mainly due to decreases in stroke volume
- (Coyle et al, 1984)
What is the effect of detraining on a-vO2 diff?
little change after 3 weeks, then gradual decline.
- (Coyle et al, 1984)
How do the adaptations to the mitochondria respond to detraining?
rapid decline
after 1 week off training, 50% of the gains from 6 weeks of training were lost. It took roughly 4 weeks to regain back what was lost in 1 week of detraining.
What are the early increases in maximal oxygen uptake with training primarily down to?
increases in maximal cardiac output (increased stroke volume)
Why may an untrained individual gain weight at the beginning of an endurance training protocol?
Increased blood volume
