L10 Muscle Training: Fibre type training and Adaptation

Question 1

Describe the development of fiber types in human skeletal muscle

Answer 1

newly formed fibers are slow contracting. They contain embryonic myosin (gradually replaced by myosin of slow or fast type) and immature ATPase.

Question 2

List the key component that affect the way training will adapt the body

Answer 2

Recruitment of motor units
Stimulus Intensity
Stimulus duration

Question 3

What us an advantage for endurance sports involving high oxygen consumption?

Answer 3

A high proportion of slow oxidative fibers

Question 4

What is an advantage for power events?

Answer 4

A high proportion of type II fast fibres

Question 5

Training studies…

Answer 5

Weightlifters showed no difference in % of type I fibers that untrained. But their muscle fibers are bigger.

In endurance training there is no fiber size change but more type IIb change to type IIa

In strength training fiber size increases but no change in fiber size

In speed training, fiber size increases for type 1 and 2. Type IIa becomes become type IIb. Glycolytic enzymes increase

Question 6

What are the 2 ways in which muscle fiber type transformation can be achieved?

Answer 6

cross-innervation
or
slow frequency stimulation of a fast muscle

Question 7

What are 3 other influences on muscle fibers?

Answer 7

Environmental - eg high altitude, reduces fibre size
Nutritional/hormonal - eg smoking or creatine
Detraining