Determinants of Endurance Performance Flashcards
What are the main 5 determinants of endurance performance?
- Peak performance values
- Thresholds
- Economy
- Oxygen Uptake Kinetics
- Haemoglobin Mass
What is the equation for marathon running speed?
VO2max x %VO2max @LT x Economy
What are the main morphological components of performance velocity or power?
- Muscle capillary density
- Stroke volume
- Max HR
- Hb content
- Aerobic enzyme activity
(also slow-twitch (Type 1) muscle fibres and anthropometry and elasticity)
Define VO2max (bonus points available)
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
Define Running economy (bonus points available)
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
Define VVO2max (bonus points available)
The interaction between VO2 and Running Economy.
- “functional expression” of VO2max
- Enable accurate prediction of 16km race (R2 + 0.94)
Define Fractional Utilisation of VO2max (bonus points available)
the % of O2 which can be utilised.
- Associated with lactate accumulaton and clearance in the blood
- Very sensitive to endurance training
What is the correlation between haemoglobin and VO2max?
Higher haemoglobin concentration = higher VO2 (small correlation)
Total haemoglobin mass has a higher correlation
-Schmidt & Prommer (2010)
How can we estimate total haemoglobin mass?
Carbon monoxide rebreathing
- Specific quantity of CO is inhaled for a specific time period, binding to haemoglobin
- dilution in blood principle allows calculation
Whack us some facts about online spirometry
- 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
What are the different chemoreceptors and what do they do?
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+
What is the equation for ventilation and acid-base balance?
(muscle) H+ + HCO3
H2CO3 CO2 + H2O (blood)
How does increased ventilation maintain a stable pH?
- 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
Define Ventilatory Threshold
The point at which ventilation increases at a faster rate than O2 consumption
How can ventilatory thresholds be determined?
plot the excess CO2 and then use the V-slope line method
Define the ventilatory equivalent for oxygen
The ratio between ventilation and VO2
Define Respiratory Compensation POint
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
What happens to the RCP at higher intensities?
It experiences a second break point
What is the point in using thresholds?
To define training zones, whether LTP or RCP
What happens when there is an inadequate O2 delivery and/or utilisation?
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)
What are the implications of using ventilatory thresholds?
+ 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
Define LT and LTP
LT - first increase in BLa conc above baseline, good predictor for marathon performance
LTP - second large increase in BLa, good predictor for 10KM performance
