Determinants of Endurance Performance

Question 1

Define VO2max

Answer 1

The maximal rate at which ATP can be re synthesised aerobically

Question 2

When is VO2max useful and not useful as endurance performance prediction?

Answer 2

Useful- When comparing athletes of varying ability

Not useful: when comparing athletes of similar ability

Question 3

What are typical VO2max values for elite men and women?

Answer 3

Men: 70-85 ml/kg/min
Women: 60-75 ml/kg/min

Question 4

Define Running Economy?

Answer 4

The oxygen cost at different running speeds

Question 5

How do you convert running economy from per minute to per km?

Answer 5

times by 60 then divide by running speed

Question 6

What is the protocol for measuring running economy?

Answer 6

Oxygen consumption is measured at a range of different speeds at constant 1% gradient to correct for air resistance

Question 7

What did Mclaughlin (2010) report when measuring the functional expression of VO2max during a 16km time trial?

Answer 7

The results showed how running speed at VO2max, determined by running economy could predict race performance (Rsquared=0.94)

Question 8

What did Burnley and Jones (2007) show between two cyclists with similar VO2max?

Answer 8

One cyclist had a fast power output at VO2max, therefore has a better economy.

More power for the same cost of oxygen

Question 9

What is fractional utilisation?

Answer 9

The % of VO2max that an athlete can perform at without dropping out of steady state.

Again, another good predictor for athletes with similar VO2max

Question 10

What does it mean to say that Haemoglobin mass is a better predictor than haemoglobin concentration?

Answer 10

Its better to have a greater total number of haemoglobin in the body than a greater % of haemoglobin per unit of blood.

Question 11

What did Schmidt & Prommer (2010) show regarding haem mass, blood volume and cardiac output?

Answer 11

All variables highly correlated with VO2max

Question 12

How do you measure haemoglobin mass?

Answer 12

using the indirect rebreathing circuit.

1) participant is breathing into the machine
2) a known quantity of CO is added into the machine
(haemoglobin has a high affinity for CO, thus all CO will be bound to haemo)
3) a pre blood sample is taken and it is assumed that the % of RBC bound to CO will be close to 0
4) take a post blood sample and calculate % of RBC bound to CO
5) for example, if 1L of CO has bound to 50% of your Hb, you have 2L of Hb in the body

Question 13

A graph presented by Joyner and Coyle, 2008 suggested what when measuring %VO2max at LT at 88% of VO2max?

Answer 13

Participants who work at greater %VO2max at LT, have greater time to exhaustion.

The study also showed that those with high capillary denisity formed a regression line of their own. Suggesting high capillary density can aid with the removal of H+ and delivery of O2

Question 14

Why is a reduced oxygen deficit beneficial to middle distant runners?

Answer 14

As they work at high performance VO2s and race time is relatively short, the time it takes to reach performance VO2 can have big implications of finishing times.

Question 15

What does Tau (t) represent? and what did the lecture graph show when comparing tau with differently abled participants?

Answer 15

The time taken to reach half an athletes expected performance VO2

The graph showed that with increased exercise training,, tau is smaller

Question 16

What are the mechanisms behind respiratory regulation?

Answer 16

Central and peripheral chemoreceptors detect changes in CO2 and H+ in the spinal cord or blood, respectively.

rate and depth of breathing increases to remove the increasing CO2

Question 17

What is the equation for pulmonary removal of H+?

Answer 17

H+ + HCO3- H2CO3 CO2 and H20

Question 18

How can a change in breathing pattern change CO2 and acidity in the blood?

Answer 18

1) increased ventilation results in CO2 exhalation. This reduces blood PCO2 and H+ concentraion (pH decreases)
2) Decreased ventilation results in a build up of CO2 and H+ (pH increases)

Question 19

Decribe and explain Ventilatory threshold?

Answer 19

The point at which there is a disproportional increase in ventilation compared to oxygen consumption. This is due to increased H+ produced by the contracting muscles. The need to buffer these protons results in increased CO2, which in turn stimulates the chemoreceptors to adjust ventilation rate and depth.

Question 20

Graph: y axis vCO2 and x axis VO2
the fact that oxygen uptake and CO2 output do not increase in the same manor allows us to find breakpoints. At what point do we find the ventilatory threshold?

Answer 20

The point at which there is a break from the linear increase shows the point where CO2 expulsion is greater than O2 consumption.

Question 21

What is Ventilatory equivalent and how is this calculated?

Answer 21

Ventilatory equivalent (Ve) is the amount of air required to take up 1L of oxygen.

Ve= L/min of total air / VO2

Question 22

Describe the relationship between exercise intensity and ventilatory equivalent?

Answer 22

Ve for O2 stays relatively constant during submax intensities, but as running velocity reaches ventilatory threshold (the point at which there is a disproportionate rise in CO2 expulsion compared to O2 inhalation), Ve goes up. Suggesting more total air is required to attain the needed O2.

Question 23

What is the Respiratory compensation point?

Answer 23

RCP is related to Maximal lactate steady state. The highest performance where lactate production and removal are at equilibrium.

Question 24

How do you determine RCP?

Answer 24

Plot total ventilation against VCO2.
As long as the increasing line is linear, the increased ventilation rate can compensate for the increasing VCO2. However, when exercise surpasses MLSS, breathing rate deviates from the linear relationship because there is too much CO2. Exercise cannot be maintained for long in this zone.

Question 25

How are lactate and ventilatory thresholds linked?

Answer 25

As lactate accumulation begins to rise above baseline, this coincides with an increase in H+ protons, causing an increase in ventilation to remove the buffered CO2.
With further increasing intensity, and as exercise surpasses MLSS, there is too much CO2 for the body to exhale so we see another increase in total ventilation (RCP)

Question 26

Anaerobic metabolism is triggered by a lack of oxygen in the cells. True of false and why?

Answer 26

False. Anaerobic metabolism is triggered by increases in H+ and CO2

Question 27

The aerobic ventilatory threshold is found at approximately the same intensity lactate begins to accumulate in the blood, why?

Answer 27

Hydrogen ions are formed and buffered, the resulting CO2 needs to be removed

Question 28

How can ventilatory thresholds be used to determine training zones according to Meyer et al., 2005

Answer 28

in the paper, ventilatory threshold was shown to seperate regenerative and extensive training; and the RCP was shown to seperate extensive and intensive training zones.

Question 29

What were the advantages and distadvantages to using ventilatory thresholds shown in the lecture slides?

Answer 29

Advantages:
- No blood sampling required

Disadvantages:

• Expensive equipment
• Mask may not be tolerated
• subjectivity of finding thresholds

Question 30

Why did meyer et al., 2005 suggest VT and RCP can be used to track performance in elite atheltes?

Answer 30

World class cyclists were shown to increase VT (8%) and RCP (6%); and top class endurance runners VT (10%) following training bouts.

Question 31

Gomez molina (2017) reported what when using regression analysis to find the best predictors of half marathon performance?

Answer 31

Models that incorporated RCP were best predictors.

Question 32

What did Takashima and Tanaka (1995) report were the best predictors of marathon performance

Answer 32

Lactate and ventilatory thresholds

Question 33

What did sheer report as best predictors for trail running performance?

Answer 33

Speed at individual anaerobic threshold and running economy.