Physiology of Endurance Athletes Flashcards
Define Endurance exercise.
Exercise that predominantly requires the oxidative aerobic systems for energy.
How does the current literature define ultra-endurance?
Events that exceed 4 hours
Events that exceed 6 hours
Events that span over days
For running it is considered to be distances greater than a marathon
What are the contributing factors to successful ultra-endurance athletes?
Long term preperation Optimal rate of movement Prevention of overtraining and injury Sufficient nutrition Psychological toughness
What are the morphological components of endurance performance?
Muscle capilary density Stroke volume Aerobic enzyme activity Distribution of power and technique Muscle fibre type composition or % of type I
What are the physiological factors influencing endurance performance?
Aerobic Capacity (VO2 max)
Lactate threshold
Improved Economy, lower O2 consumption and fuel consumption
Performance VO2, sustaining a higher % of VO2 max
Fuel supply, improved ability to oxidate fats at submax - delay use of glycogen stores.
Which 3 measures will improve endurance performance?
VO2 max
Lactate threshold
Running Economy
Define Vo2 max?
Maximum rate at which an individual can take-up and utilise oxygen whilst breathing air at sea level
What are the central and peripheral limiting factors for Vo2 Max?
Central: Pulmonary diffusing capacity
Maximal Cardiac output
Oxygen carrying capacity of the blood
Peripheral: Skeletal muscles characteristics
How does lactate accumulation occur?
Due to an increased lactate produciton via increased rate of glycolysis.
Rate of appearance exceeds the rate of disappearance.
Why doesnt lactate accumulate at rest?
Muscle activity of the glycolytic pathway is low and fat is the main utlised energy source.
How are lactate and fatigue related?
As lactate is produced a H+ is released. H+ decreases pH.
Decrease pH = inhibition of PFK which is a rate limiting enzyme. Also inhibits Ca+ release = impaired muscular contraction.
What is lactate threshold?
Lactate threshold is the point where blood lactate begins to accumulate above resting levels.
One of the most important limitations of exercise performance in endurance athletes.
What value is OBLA?
4 mmol.
What does running economy measure?
Running economy measures oxygen consumption at a given running speed.
5% improvement in running economy = 3.8% improvement in Vo2 max.
