take it to the limit 17

vo2

the highest rate at which the body can take in, transport and utilize oxygen to perform muscle work

modifications in vo2 factors will result in

changes to vo2 max

what would it take to make sub2 in a marathon

• maximal aerobic power (VO2 max)

• Critical speed

• economy of movement

• envionrmental conditions

take in oxygen

• inhaling

• oxygen diffusion into blood

transport of blood

• oxygenated blood is distributed to working muscles

• oxygen diffuses into muscles

utilize oxygen

• diffusion into mitochondria

• oxygen is consumed during the ETC to produce O2

gas exchange =

more blood flowing to alveoli + more capillaries

Ventilator limitations of Vo2 max (take in)

lung capacity and alveoli capillary perfusion

transport limitations on Vo2 max

• blood hemoglobin levels predict vo2 max

• HR

• Cardiac Size

limit to vo2 max which isn’t modifiable/trainable

• HR

muscular limitations of vo2 max

• oxygen diffusion into mitochondria

• capillary and mitochondrial density

combination of factors resulting in elite vo2 max

• lung size and alveolar capillary perfusion

• blood vol and hemoglobin content

• heart size, HR, vascular conductance

• fibre type (capillary and mitochondrial density)

threshold intensity

• describes maximum sustainable intensity during sustained exercise

• balance between lactate and H production and clearance

improved oxygen supply limits

need for lactate and H+ production

improved lactate and H+ clearance limits

fatigue

how to increase lactate clearance

• increased in MCP transporters

• Bicarbonate concentration

• Resting PH

untrained vs trained lactate

untrained ppl produce more lactate but if it’s cleared at higher rates then it won’t accumulate

critical power better at predicting

performance in long events than vo2 max

increasing threshold 2 (anaerobic threshold)

When you increase your LT2, you're essentially pushing back the point at which lactate starts to accumulate rapidly

increased threshold intensity

• better oxygen delivery and improved clearance prevents accumulation

a greater running economy enables a runner to

• run at the same speed at a lower energy expenditure

• run at a faster speed at the same energy expenditure

running economy":

the energy cost of maintaining a given intensity

primary factors of running economy

• swing mass (moment of inertia)

• midsole cushioning

• longitudinal bending stiffness

generation of propulsion

• Muscular generation of forces

• energy is lost in sole bending and energy return

impact of landing

• muscular absorption of forces

• energy lost in sole compression/energy return

energy is expended to (footwear)

minimize impact and generate propulsion

shoe cushioning minimizes

• muscle cushioning activity

• if you have a more cushy shoe then your leg has less to absorb and uses less energy

arch stiffness and running

• stuffer arch returns more cushioning energy back into propulsion energy

Swing mass

• the heavier the mass is or the further the mass is from the axis of rotation the more torque is required to move the limb

temperature and running

• temp decides where blood flow

• heat increases blood flow to skin to assist in cooling which is blood that is not travelling to the exercises muscle which will make vo2 dropa

envionrment altitude

high altitudes reduces PO2 of ambient air and limits oxygen diffusion into blood

VO2 MAx drops 5-10% for each

1000m increase in elevation

pollution and race env

• pollution stimulates bronchoconstriction and vasoconstriction to limit ventilation and blood flow to working muscles

sub 2 hour marathon =

• high vo2 max

• high speed at LT2

• high running economy

• course with optimal conditions