Lecture 2 - Physiology of the Endurance Athlete Flashcards
What are the considerations for ultra endurance training programs?
- Long term periodization
- Optimal rate of movement
- Overtraining & prevention of injuries
- Sufficient nutrition
- Psychological toughness
What physiological factors can be measured so gauge performance capacity.
- Maximal 02 consumption
- Lactate threshold at Vo2
- Economy of movement
- Power or velocity at lactate threshold
- Performance Vo2
As exercise time increases what does the increases in RA of citrate synthase indicate?
- indicated that the \kerbs cycle is working, thus meaning that CHO is being used to supply energy.
Definition of lactate threshold?
The exercise intensity associated with a substantial increase in blood lactate during an exercise test.
How do you define endurance exercise ?
- Exercise beyond 5 minuet and less than four hours that predominantly require the oxidative (aerobic) system for energy.
Why does acidosis as a result of high intensity exercise cause an athlete to slow down
- The acidosis is a build up of the H+ ions.
- These inhibit the PFK (phosphofructokinase) and release of Ca+.
- This result in a reduced level of contractile ability from the muscle, therefore reducing force output and speed.
What is the classification of ultra endurance events?
- Exceed four hours
- Exceed six hours
- Exceed 40 hours or even days.
What are the physiological factors that influence endurance performance ?
- Aerobic capacity (Vo2max)
- Lactate threshold
- Economy ( Better economy = lower 02 consumption)
- Performance Vo2 (easier to sustain higher as relative intensity is easier.
- Fuel supply (improved fat utilisation)
How does lactate level increases come hand in hand with fatigue.
- As lactate is produced H+ ions are released.
- These change the cell PH causing inhibition of PFK and Ca+ release.
- This then effects muscular contraction ability and subsequent fatigue ensues.
What is the definaiton of Vo2max?
- The highest amount of O2 an individual can take in and utilise to produce ATP aerobically while breathing air during heavy exercise.
What is the blood lactate level at rest and why does it accumulate during exercise?
- During rest level is 0.5 - 1.5 mmol/L
- Increases during exercise as RA raises above RD due to lack of O2 and increase rate of anaerobic glycolysis.
What are the limiting factors for Vo2max?
-Central limitations such as pulmonary diffusing capacity, Qmax, oxygen carrying capacity of blood.
Peripheral limitation such as mitochondrial content.
What are the three factors that can influence endurance performance?
- Aerobic capacity
- Lactate threshold
- Economy of effort
Explain why muscle capillary density, stroke volume and aerobic enzyme activity impact Vo2max.
- Capillary density impacts Vo2max because even if the blood supply is high if there is a poor level of capillary density this is not going to slow the blood and extract the o2 from it.
- Stroke volume impact this as if the heart is unable to supply the muscle with o2 then they are going to fatigue faster, even if capillary density is high.
- Enzyme activity impacts this because If his is higher it is going to allow greater oxidation of fat for energy, therefore reducing need for anaerobic glycolysis.
Why would an athlete with an improved economy have a better lactate threshold.
- The improved economy would result in a better use of the available energy.
- This would then result in perforce being maintained at a higher level for longer whilst still utilising the aerobic system.
- In comparison to the other athlete who is going to finding the exercise harder from the offset, so is going to be working at a relative higher % of their VO2max.
