Physiology of the Endurance Athlete

Question 1

Define Endurance exercise from a time & physiological perspective.

Answer 1

• 5 mins - 4 hours
• ◦ Exercise that predominantly requires the
  Oxidative Systems for energy.

Question 2

State physiological factors affecting endurance.

Answer 2

• VO2max
• Lactate threshold
• Running economy
• Performance VO2
• Fuel supply

Question 3

Define VO2max

Answer 3

- The highest amount of oxygen an individual
can take in and utilise 
- to produce ATP
aerobically 
- while breathing air during heavy
exercise @ sea level

Question 4

Why does acidosis as a result of high intensity

exercise cause an athlete to slow down?

Answer 4

• As lactate is produced a proton (H+) is released.
• These protons can then decrease pH (more acidic
  environment)
• The decreased pH inhibits PFK (rate limiting enzyme)
  also inhibits Ca+ release, affecting muscular
  contraction

Question 5

What are the best physiological factors to distinguish between runners?

Answer 5

• Running economy
• Running velocity at VO2max
• Blood lactate measures

Question 6

Why would an athlete with an improved running

economy have a better lactate threshold velocity?

Answer 6

• RE is the energy demand for a given velocity
• Lower energy demand = lower glycolysis = lower lactic acid
• Thus athlete can run at a higher velocity for the same lactic acid production due to a lower energy demand

Question 7

Explain why a greater percentage of slow twitch
skeletal muscle fibre is associated with improved
running economy?

Answer 7

• Higher % of mitochondria
• More oxidative phosphorylation
• Using oxygen more efficiently than anaerobic