Week 2: Applied Physiology of Human Performance Flashcards
Endurance performance is….
- Greater than …. minutes
- 60-….% V02max
- ATP demand?
- 30 minutes
- 60-85% of V02 max
- <2.5mmol/kg/dm/s (relativey low to alllow us to maintain this duration of exercise)
Major limiting factors to endurance performance? What affects these factors?
Hydration status (fluid intake -if you start from a dehydrated state your performance is going to be limited)
Both affected by behaviour (intake during, before & after) and environment (eg heat = negative on hydration and warmer weather = increase in glycogen use
Goals of endurance overload training
- Increase rate of oxidative ATP supply
- Oxidative phosphorylation of CHO and lipid fuels
- Increased work while avoiding fatigue with oxidative metabolism
Mechanisms of endurance training
- Increase 02 supply by blood
- Increase fuel supply (carbohydrate, glycogen or lipid stores)
- Improve extraction from blood
- Muscle (morphological changes – fibre types)
- Improved metabolism
Central adaptations from endurance training
central: develop functional capacity of the central circulation. Includes the following:
Increased plasma volume & increased red blood cell mass
This increases total blood volume.
Which increase ventricular compliance, internal ventricular dimensions, venous return, myocardial contractility.
Increased end diastolic volume and increased ejection fraction.
Overall increased stroke volume.
This increases cardiac output ie increased blood flow to active muslce
Peripheral adaptations from training
peripheral: enhance aerobic capacity of the specific muscles
Includes the following:
- change in fibre type
- increased myoglobin
- increased capillary density
- increased 02 diffusion
- increased krebs cycle enzymes
- increased lactate clearance
- increased muscle buffering capacity
- increased mitochondrial density
- increased mitochondrial protein synthesis
- increased intramuscular storage
What equation can be used to model some of the effects of central and peripheral adaptations on oxygen consumption? Explain its components.
Fick equation
V02 = HR x SV x (a-v)02diff
HR & SV= central
(a-v)02diff = peripheral
How important is V02max for performance?
High absolute V02max is needed! In a study it was found that those with a higher v02 max had a higher average racing speed
What are the key determinants of endurance performance
- V02max
- Anaerobic threshold
- Movement economy
1& 2 affect performance V02 and rate of ATP synthesis.
1,2 & 3 affect mean race/pace and power output
What happens in relation to blood volume after endurance training?
Physiological adaptations from endurance training.
It increases as a result of increased hematocrit & increased plasma volume
What happens in relation to stroke volume after endurance training?
Physiological adaptations from endurance training.
SV increases due to increased contractility & increased ventricular volume
What happens in relation to heart rate after endurance training?
Physiological adaptations from endurance training.
Decreased submaximal HR (HRmax unchanged)
What happens in relation to cardiac output after endurance training?
Physiological adaptations from endurance training.
Cardiac output increases due to stroke volume
What happens in relation to 02 extraction after endurance training?
Physiological adaptations from endurance training.
Increased (a-v)02 difference
- Red cell 2,3-diphosphoglycerate (2,3, DPG)
- Angiogenesis = capillarisation
- Myoglobin
What happens in relation to blood pressure after endurance training?
Physiological adaptations from endurance training.
Decrease systolic and diastolic at rest and during exercise