Phenotypic characteristics of RT athlete

Question 1

Relationship between RT and muscle length?

Answer 1

Cannot make muscle longer - bones, tendons, ligaments determine length

Question 2

Where does highest rate of muscle growth occur?

Answer 2

Mid-belly of muscle, lesser at proximal+distal ends

Question 3

What is the pennation angle?

Answer 3

Angle of muscle fascicle as it emerges from aponeurosis

Question 4

What is the primary mechanism of muscle growth?

Answer 4

Increased radial growth

Question 5

What is the primary driver of an increase of whole muscle growth?

Answer 5

Significant increase in type II fibre CSA (Aagard et al 2001)

Question 6

What is cell swelling?

Answer 6

Expansion of non-contractile elements of fibres (sarcoplasmic hypertrophy). - could suggest why bodybuilders are bigger yet weaker than powerlifters.

Question 7

Is radial growth driven by sarcoplasmic hypertrophy?

Answer 7

Mac Dougall et al 1982 - NO - by a proportional increase in both force-generating and non-force generating elements.

Question 8

Describe the myofibril expansion cycle

Answer 8

1) cycle begins with deposition of new myofilaments around periphery of pre-existing myofibrils (hypertrophy)
2) Once myofibrils reach critical size, they split into 2 daughter myofibrils
3) Daughter myofibrils then enters another round of cycle, repeat.

Question 9

What do satellite cells do (with regards to hypertrophy)?

Answer 9

Support recovery, repair muscle damage, provide new nuclei for muscle cell.

Question 10

Satellite cells process is governed by which 2 key proteins?

Answer 10

• MRF4
• myogenin

Question 11

In terms of a nuclei, what happens if muscle fibre size increases?

Answer 11

Any area of muscle fibres metabolic actions are governed by a nucleus. If myofiber size increases, nucleus has larger part of cell to be responsible for = need more myonuclei to support.

Important* - Myonuclear domain is kept constant