Physiology of the Endurance Athlete

Question 1

Endurance performance considerations

Answer 1

Nutritional considerations:

• fuel utilisation (high CHO %)
• Carbohydrate absorption during exercise (> 60g)

Dehydration of ≈ 2-3% reduces endurance performance

Environmental considerations:

• Hot and cold environments
• Altitude

Question 2

V02max vs performance

Answer 2

Not the strongest predictor of performance but…

VO2max represents the maximal rate of ATP generation aerobically, & therefore, provides an upper ceiling for endurance performance.

Question 3

Lactic acid

Answer 3

Lactate is a fuel

Allows glycolysis to continue

1:1 ratio of lactate to H+

Therefore increase in lactate = increase in H+

Question 4

Gross Efficiency

Answer 4

Gross efficiency is ratio of power output to energy expenditure

Work accomplished / energy expended x 100

Question 5

Mechanisms of gross efficiency

Answer 5

Muscle fiber type distribution. Increased type 1 %.

Decrease in Mitochondrial uncoupling.

Question 6

What corresponds to A,B and C in the endurance athlete figure?

Answer 6

A = VO2max 
B = Lactate Threshold 
C = Running Economy

Question 7

Describe how an increase in muscle capillarisation affects a-vO2 difference?

Answer 7

Increased capillary density in muscle

Increase in mean transit time

Maintenance of a-vO2 diff. even at high intensity

Question 8

How does training in a muscle glycogen depleted state improve endurance performance?

Answer 8

Results in enhanced mobilisation of fatty acids for fuel

Results in enhanced use of fatty acids for fuel

Spare glycogen = deferred accumulation of waste products associated with glycolysis