Increasing VO2max with endurance training:
1. Increased in stroke volume:
-VO2max training increases the preload = the heart’s muscle fibres can stretch
-If there fibres stretch more, the ventricles can expand more and more blood to flow into
the ventricles.
-If more blood can flow in = the volume of blood is higher
-Therefore the “end diastolic volume” is higher  The volume of blood pumped out of the
heart will be greater.
This is because:
With higher volume pumped out then:
*Venous pressure must increase to pump blood back to the heart
*The venous return (amount of blood returning to the heart) will increase
*Plasma volume must increase
*All leading to an overall increase in ventricular volume  the volume of blood in the
ventricles will be greater from all these factors together
2. A decrease in afterload
With VO2max training the total peripheral resistance (TPR) will decrease
- If the blood that is being pumped out of the heart has less resistance to overcome when it
needs to travel to the extremities (i.e. your big toe) then it will be easier and more efficient
for your heart to pump it around your body.
*So, to make the peripheral resistance less:
There will be a reduction in arterial vasoconstriction  the blood vessels (especially the
arteries) will increase their diameter to allow blood to flow more smoothly.
Vasoconstriction = make blood vessels smaller
Vasodilation = make blood vessels bigger
ThereforeVO2mx training will help reduce the resistance that the blood must overcome by
reducing the amount of vasoconstriction in the blood vessels to allow maximum amount of
blood to flow to muscles.
If this happens, there will be no change in the mean arterial pressure as there is a higher
volume of blood flowing through a larger area of blood vessels.
3. Increase in contractility
The increase in contractility refers to the muscle fibers in the heart.
VO2max training helps the muscle fibers in the heart contract more efficiently to reduce the
workload on the heart.
4.
A-vO2 difference
i.e. the difference in oxygen content in the arteries and veins
VO2max training will increase the amount of blood flowing to the muscles = more oxygen is
taken to the active muscles.
For this to happen:
The activity of the Sympathetic Nervous System (SNS) needs to be reduced.
If vasoconstriction in the body is reduced =increased vasodilation  the blood vessels will
dilate and increase in diameter to allow more blood to flow to active muscles.
Also, there is an improved ability for the muscles to take up the oxygen from the blood 
Increased capillary density = more capillaries = more blood flow
Increased mitochondria = more ATP can be produced