Exercise Phys. Lecture 3

winniesmith2's version from 2018-01-04 15:02

Section 1

Question Answer
Who has the highest aerobic capacity?those with the most muscle mass, higher cardiac output, higher heart rate
Why use V02 max as a measure for aerobic capacity ('aerobic fitness')Because there are so many systems in the oxygen transport change, using VO2 max includes all of these, as they all link together, VO2 max captures all systems
What is the oxygen transport system -> Pulmonary ventilation -> Hb concentration -> Blood volume and cadiac output-> Peripheral blood flow -> Aerobic metabolism -> back to pulmonary ventilation.
Aerobic contribution VS exercise durationfirst min (0-60)uses ATP-CP system for energy
Aerobic contribution VS exercise durationapprox 60-120 seconds uses glycolysis system for energy
Aerobic contribution VS exercise duration120 seconds +uses oxidative system for energy, slowly increasing from 0 seconds.
What percentage of the energy system does 100m event use90% anaerobic, 10% aerobic
what percentage of the energy system does 400m event use75% anaerobic, 25% aerobic
what percentage of the energy system does 1500m event use25% Anaerobic, 75% aerobic
what percentage of the energy system does 10,000m event use3% anaerobic, 97% aerobic

Section 2

Question Answer
What does V02 max depend on A good cardio-vascular system and high cardiac output. Well-developed oxidative capacity in skeletal muscle (e.g. mitochondria, oxidative enzymes etc).
What are the peripheral limitations on VO2 max Isolated muscle can use more oxygen than the heart can deliver. (e.g., one vs two legged exercise: O2 extraction by quadriceps during one-legged exercise is 2-3 times higher than that measured in the same muscle group during whole body exercise)
Longditudial aerobic training studies looking at VO2 max show: – 2.2 fold increase in mitochondrial enzymes, but only ~20-40% increase in Vሶ O2max – Individuals with a similar Vሶ O2max exhibit two-fold range of mitochondrial enzymes. Cardiac output = limiting factor.
What did the training study by Montero 2015 show Reducing blood volume through phlebotomy after training (to pre-training levels) reduces both cardiac output and VO2max to pre-training levels. Therefore Oxygen delivery and thus V02 max is primarily limited by stroke volume.
Explain stray-gundersens 'A dogs story' storyRemoval of the pericadium (lining of heart) increased SV, which increase cardiac output and increase in V02 max.
VO2 max- graph of what effects it Pg 3, slide 13 lecture 3
What is a 'good' VO2 max; absolute and relative score?Depends on individual. Divide VO2 max L/min by weight Kg, to get relative VO2 max.
When assessing fitness using relative VO2 max , why do men have higher values than females?As men have higher amount of lean muscle mass, more active muscle mass. Fat mass barely takes place in metabolism so we change it to make comparison fair.
When to perform surgery or not?– VO2max < 10 mL/kg/min or < 40% predicted: NO! – VO2max > 20 ml/kg/min or > 75% predicted: YES!

Section 3

Question Answer
What effect does Age have on VO2 maxAfter the age of 25, ~1% decrease/year • During ageing, more rapid decline (may be confounded by disease). However training can still increase this.
How does Heredity effect VO2 max• Genetics accounts for 25-50% of the variance in Vሶ O2max between different people • e.g., typical world-class distance runner – Vሶ O2max = 85 mL/kg/min – Deconditioned value: 65 mL/kg/min
What is the protocol design to determine VO2 max Incremental exercise test to exhaustion • Vሶ O2maxAim for protocols where exhaustion is achieved within ~8-12 minutes – Too short protocols: Exhaustion due to peripheral limitations – Too long protocols: Exhaustion due to duration • Large muscle group (cycling, running, rowing) – Stresses maximum cardiac output – Avoids premature local muscle failure
What is the primary criterion for Max oxygen uptake (definition ACSM/BASES guidelines)Plateau in VO2 despite load/speed increase to next stage (Less than 2 mL/kg/min)
What is the secondary criteria for Max oxygen uptake (definition ACSM/BASES guidelines)– HR within 90% of age-predicted maximum (220-age) – Blood lactate concentration over 8 mmol/L (indication of large contribution of anaerobic metabolism) – Respiratory exchange ratio (RER) (Vሶ CO2/Vሶ O2) of 1.15 or above (indication of large contribution of anaerobic metabolism). • Not all individuals show all criteria •  Vሶ O2peak (indicates the peak oxygen uptake reached in the specific test). The term “Vሶ O2peak” is also used for smaller-muscle group exercise
When do you use V02 peak if they have not reached V02 max in that specific test
Other determinants of endurance performance Ability to use oxygen is the main physiological determinant of endurance performance – Vሶ O2maxmaximal capacity (“upper limit”) BUT EQUALLY IMPORTANT: – Ability to sustain a high percentage of Vሶ O2max over the time of the race – Ability to produce high power/speed at a given oxygen uptake (economy, technique)