6.1 Muscular Adaptations to Endurance Training

Question 1

Structural Adaptations within muscle

Answer 1

Changes in muscle fibre composition (<– type IIx –> Type IIa).
–> capillary density in all muscle fibre types.
–> mitochondrial size and density
–> oxidative enzymes

Question 2

Muscle biopsy

Answer 2

Study of muscle fibres & effects of acute and chronic exercise training on fibre composition.

Question 3

Greater capillary density causes:

Answer 3

Improved O2 extraction
– Greater surface area for O2 uptake
– Shorter diffusion distance
– Slower blood flow
– Increased red cell transit time

Question 4

Mitochondria:

Answer 4

Powerhouse of cell
Convert nutrients into ATP (produces energy)
* Through process of oxidative
phosphorylation.

Question 5

Glycolysis

Answer 5

Glucose/glycogen (glycogen phosphorylase) –> 2 pyruvate + 2-3 ATP

Question 6

Oxidative Pathway

Answer 6

Acetyl-CoA (fatty acids) –> Krebs cycle –> oxidative phosphorylation —> H20 + CO2 + 38-39 ATP (fat)

Question 7

what is glycogen phosphorylase

Answer 7

enzyme that breaks down glycogen

Question 8

Increased availability of oxidative enzymes

Answer 8

→ Increased capacity for oxidative metabolism
→Increased aerobic capacity

Question 9

Reduced Anaerobic Glycolysis

Answer 9

Improved oxidative capacity in type I fibres may delay recruitment of type II fibres
(train at higher intensity using type I).
* Type II fibres may also increase oxidative capacity if recruited during training (type IIx → type IIa)