Determinants of Endurance Performance

Question 1

What are the main 5 determinants of endurance performance?

Answer 1

• Peak performance values
• Thresholds
• Economy
• Oxygen Uptake Kinetics
• Haemoglobin Mass

Question 2

What is the equation for marathon running speed?

Answer 2

VO2max x %VO2max @LT x Economy

Question 3

What are the main morphological components of performance velocity or power?

Answer 3

• Muscle capillary density
• Stroke volume
• Max HR
• Hb content
• Aerobic enzyme activity
  (also slow-twitch (Type 1) muscle fibres and anthropometry and elasticity)

Question 4

Define VO2max (bonus points available)

Answer 4

Maximal rate at which ATP can be aerobically resynthesised

• Strong correlations with endurance performance
• Measure of success from training interventions
• Elite runners 60-75 (F), 70-85 (M) ml/kg/min

Question 5

Define Running economy (bonus points available)

Answer 5

The O2 cost of running at a submaximal speed

• Significant inter-variability, influenced by anthropometric, physiological, biomechanical and technical factors
• Generally better used in long-distance specialists

Question 6

Define VVO2max (bonus points available)

Answer 6

The interaction between VO2 and Running Economy.

• “functional expression” of VO2max
• Enable accurate prediction of 16km race (R2 + 0.94)

Question 7

Define Fractional Utilisation of VO2max (bonus points available)

Answer 7

the % of O2 which can be utilised.

• Associated with lactate accumulaton and clearance in the blood
• Very sensitive to endurance training

Question 8

What is the correlation between haemoglobin and VO2max?

Answer 8

Higher haemoglobin concentration = higher VO2 (small correlation)
Total haemoglobin mass has a higher correlation
-Schmidt & Prommer (2010)

Question 9

How can we estimate total haemoglobin mass?

Answer 9

Carbon monoxide rebreathing

• Specific quantity of CO is inhaled for a specific time period, binding to haemoglobin
• dilution in blood principle allows calculation

Question 10

Whack us some facts about online spirometry

Answer 10

• Allows realtime breath-by-breath analysis
• Rate at which O2 uptake rises to meet “steady state” exercise requirements
• A faster adaptation reduces oxygen deficit, particuarly important in middle-distance runners

Question 11

What are the different chemoreceptors and what do they do?

Answer 11

Central chemoreceptors - CO2 increases alter the pH of cerebrospinal fluid, increasing breathing depth and rate to remove CO2

Peripheral chemoreceptors - located in aortic and carotid bodies, ensitive to PO2, PCO2 and H+

Question 12

What is the equation for ventilation and acid-base balance?

Answer 12

(muscle) H+ + HCO3

H2CO3 CO2 + H2O (blood)

Question 13

How does increased ventilation maintain a stable pH?

Answer 13

• Excess CO2 stimulates central and peripheral chemoreceptors, increasing ventilation
• This means CO2 is exhaled, reducing PCO2 and H+ in the blood (pH increase)
• Decreased ventilation will result in a CO2 build-u, therefore lowering pH

Question 14

Define Ventilatory Threshold

Answer 14

The point at which ventilation increases at a faster rate than O2 consumption

Question 15

How can ventilatory thresholds be determined?

Answer 15

plot the excess CO2 and then use the V-slope line method

Question 16

Define the ventilatory equivalent for oxygen

Answer 16

The ratio between ventilation and VO2

Question 17

Define Respiratory Compensation POint

Answer 17

the point at which acidaemia (low pH) takes over from CO2 as the stimulus for ventilation, either resulting in an increase in ventilation or termination of exercise

Question 18

What happens to the RCP at higher intensities?

Answer 18

It experiences a second break point

Question 19

What is the point in using thresholds?

Answer 19

To define training zones, whether LTP or RCP

Question 20

What happens when there is an inadequate O2 delivery and/or utilisation?

Answer 20

1) sympathetic drive works alongside type 2x recruiment to trigger…
2) anaerobic metabolism (increasing lactate)
3) as lactate removal is limited, buffering occurs to decrease HCO3- and increases VCO2 and ventilation
4) minute ventilation experiences
a) nonlinear increases
b) delayed steady-rate
5) Respiratory compensation for metabolic acidosis occurs (increasing minute ventilation and decreasing PaCO2)

Question 21

What are the implications of using ventilatory thresholds?

Answer 21

+ no blood sampling required
+can be used in tracking performance
+ O2 uptake alongide LT and age are the best predictors for marathon times
- expensive equipment
- mask/mouthpiece not tolerated by everyone

higher thresholds will be found in well-trained individuals

Question 22

Define LT and LTP

Answer 22

LT - first increase in BLa conc above baseline, good predictor for marathon performance
LTP - second large increase in BLa, good predictor for 10KM performance