Lecture 2 - Determinants of Endurance Performance

Question 1

How do you calculate economy ?

Answer 1

Multiply O2 uptake in ml/kg/min by 60 and divide by the running speed in km/h.

Question 2

How does may ventilatory threshold and RCP increase during season?

Answer 2

• ~8% (VT) and 6% (RCP) in world class cyclists

- ~10% (VT) in top-class endurance runners

Question 3

Why are good O2 uptake kinetics important in middle distance runners?

Answer 3

Important because if this is limited then this means that the athletes are in a greater state of oxygen deficit when starting the run, meaning there are going to build higher levels acidosis and lactate than the other athletes how my have better.

This will mean that they will have cut more into their carbohydrate stores and potentially be run out of the race when the speed picks up again, or fatigue early.

Question 4

What are the four influencing areas of economy and some examples of each ?

Answer 4

• Anthropometric measures (Muscle attachments, Fibre type,)
• Physiological (VO2max, LT,)
• Biomechanical (Tendon stiffness for energy storage and return, Muscle length change rates for RFD and transmission )
• Technical (Efficiency of moment, footwear)

Question 5

What is more important having a high % of red blood cells or a higher total volume of red blood cells and why ?

Answer 5

A higher total number is better because there is an upward correlation with this towards VO2max values.

Question 6

Why happens to ventilation when CO2 increases?

Answer 6

Ventilation increases because excess Co2 stimulates central and peripheral chemoreceptors.

It is more to get CO2 out than to get O2 in.

Question 7

What are the main determinants of endurance performance ?

Answer 7

• Peak Performance values
• Thresholds
• Economy
• Oxygen uptake kinetics
• Haemoglobin mass

Question 8

What is the benefit to having a high capillary density for oxygen uptake and H+ removal ?

Answer 8

More capillaries increases the mean transit time of the blood, allowing greater extraction. This allows more aerobic metabolism to be performed, therefore reducing reliance on anaerobic glycolysis to produce energy.

Question 9

The respiratory compensation point (RCP) occures when ?

Answer 9

The highest exercise intensity at which changes in respiration manage to compensate the increases in H+.

It is equal to the MLSS.

Question 10

Practicalities of ventilatory thresholds for training prescription?

Answer 10

• Advantages - No Blood sampling required.

- Disadvantages - Expensive, tolerance of mouthpiece.

Question 11

Why are VO2 kinetics important ?

Answer 11

VO2 kinetics are important as the greater your ability to switch on your aerobic energy supply the less you cut into your anaerobic system and energy stores.

Question 12

What are the subsequent effects if there is inadequate O2 delivery?

Answer 12

1 - Inadequate O2 delivery
2 - Increased anaerobic metabolism via sympathetic drive, type 2x recruitment or reduced lactate removal.
3 - protons are buffered.
4 - CO2 rises increase VE (minute ventilation)

Question 13

Why is Economy important for endurance performance ?

Answer 13

Important because economy represents the efficiency of oxygen that is used.

In two athletes with the same VO2max the one with a lower economy is able to sustain their performance for longer as they are using a lower % of their VO2max to run at the same speed.

Question 14

What did McLaughlin (2010) state about running speed at VO2max and how this relates to economy.

Also what distance is VO2max running speed a good indicator of ?

Answer 14

The greater the VO2max running speed the better the economy is and can explain differences in performance in athletes with similar VO2max values.

• A good indicator of 16km race performance.

Question 15

Why does ventilation increase disproportionately to oxygen consumption during incremental exercise?

Answer 15

Blood CO2 increases in a nonlinear fashion and needs removing, as such with rapid jumps in CO2, ventilation will respond.

Question 16

What is the out and out most important factor in successful performance?

Answer 16

Power output

Question 17

What is the testing method to assess running economy by Jones AND Doust (1996)?

Answer 17

Running at a range of speeds used in training with a 1% grade. Get the O2 values at each speed and calculate economy from this.

Question 18

How do you estimate total haemoglobin mass/ blood volume as reported by Siebenmann et al., (2017) ?

Answer 18

• Take a pre blood sample breathing normal air looking at CO content.
• Add in a known quantity of carbon dioxide (CO) for 10 mins. e.g 1 litre
• Take another blood sample.
• Difference in percentage blood CO can be extrapolated to give full volume.

So if you added 1 litre of CO and % CO in blood rose to 20% then you would know that 100% would be 5 litres.

Question 19

What is RCP?

Answer 19

Respiratory compensation point.

It is the seconds break point in VE (Minute ventilation).

The Respiratory point in line with the MLSS, where lactate RA + RD is equal.

Question 20

If an athlete had a VO2max or 85ml/kg/min, an economy of 160ml/kg/km and can sustain 80% VO2max over 10km how fast can they run a 10k

Answer 20

Multiply VO2max by %VO2max to get performance VO2.

Then divide economy by this figure to get speed per km.

Multiply this by 10 then adjust the recalculate the seconds so they are out of sixty instead of 100.

So - 85 / 0.80 = 68
160 / 68 = 2.35
2.35 x 10 = 23.5
60 / 100 x 50 = 30
Time is 23.30 mins

Question 21

When assessing the O2 uptake kinetics if an elite athlete can be at 100% in 1 minute why might their towl be 10 seconds if this is meant to shown the half way point ?

Answer 21

It can be 10 seconds because the first half rises quickly whereas the seconds half to reach 100% can take the other 50 seconds.

Question 22

The aerobic ventilatory threshold is found at approximately the same intensity lactate begins to accumulate in the blood ( Lactate threshold) – WHY?

Answer 22

Hydrogen ions are formed and buffered, the resulting CO2 needs to be blown off.

When LT occur this is the first significant point where there is a raise above baseline so will be shown by increased CO2 presence.

Question 23

What are the three components of the performance velocity power equation as reported by Joyner AND Coyle (2008) ?

Answer 23

(Performance VO2 + Performance O2 deficit) x Gross Mechanical Efficiency.

Question 24

What is the ventilatory equivalent for oxygen and how do you calculate this if VE is 90L/min and VO2 is 2L/min ?

VE = Minute ventilation volume

Answer 24

It shows the amount of air you need to breath in to get a set amount of oxygen in.

So VE of 90 means for a VO2 of 2L/min means need to take in 45 litres of air to get 2 litres O2

To calculate ventilatory equivalent = VE/VCO2

So
90/2 = 45

Question 25

How does Mayer et al., (2005) base their training zones around ventilatory data?

Answer 25

• Regenerative zone below ventilatory threshold
• Extensive zone between threshold and RCP
• Intervals between RCP and MAX

Question 26

What is the formula for marathon running speed ?

Answer 26

(VO2max x %VO2max @ LT) x Economy

Question 27

What are some mechanisms the regulate respiration?

Answer 27

• Central chemoreceptors sense CO2 increases in cerebrospinal fluid and increases rate and depth of breathing.
• Peripheral chemoreceptors in aortic and carotid bodies - sensitive to blood PO2, PCO2, H+

Question 28

What is the main buffer within the human body and how does it work?

Answer 28

Bicarbonate

It reacts with the proton to create carbonic acid which then split into into CO2 and H20.

So H+ + HCO3- becomes H2CO3 which splits into CO2 + H20

Question 29

What is the main driver for ventilation ?

Answer 29

CO2 and H+ ions

Question 30

What ventilatory point does lactate threshold coincide with ?

Answer 30

First ventilatory threshold

Question 31

What is fractional utilisation ?

Answer 31

The Highest % of VO2max that can be sustained whilst still maintaining an equilibrium.

It would usually equate to MLSS and RCP but really represents the percentage of your VO2max you are working at.

• So when walking you fractional utilisation may be 20%
• Whereas during a marathon it could be 75%

Question 32

Joyner AND Coyle (2008) stated that performance velocity was made up of the following equation - (Performance VO2 + Performance O2 deficit) x Gross Mechanical Efficiency.

What are the components that make up each section ?

Answer 32

• Performance VO2 (Lactate threshold, Vo2max, capillary density, stoke volume, max hr, haemoglobin content, enzyme activity, power distribution)

Performance O2 deficit - (Buffering capacity, distribution of power output)

Mechanical efficiency - (slow twitch fibre %, anthropometry and elasticity)

Question 33

What are the components that make up the average race pace, and there downstream effects?

Answer 33

Average race pace = aerobic energy expenditure (VO2max, fractional utilisation, energy contributions) + Economy.

Question 34

What would be considered elite male and female VO2 max values ?

Answer 34

Males - 70-85 ml/kg/min

Females - 60-75 ml/kg/min

Question 35

What happens to ventilation up until the RCP?

Answer 35

It increases linearly to blow off excess CO2.

Question 36

How do you calculate ventilatory equivalents for both O2 and CO2 if VE is 60L/min, VO2 is 2L/min and VCO2 is 1.5L/min ?

Answer 36

VE/ VO2 or VE/VCO2

E.g 60/2 = 30 litres intake

60/ 1.5 = 40 litres exhale.