Chapter 4 - Neuromuscular Function & Fatigue

a) Types of muscle contraction

1. Isotonic

-contraction that causes the
muscles to shorten to overcome
resistance involved 2 phases: Concentric (muscle shortens) and Eccentric (muscle lengthens)

2.Isometric

- static contraction (no change in
the length)

3. Isokinetic

- performed with a constant
speed throughout the movement.
(muscle changes length, constant
speed)

b)Fast twitch fiber vs slow twitch fiber

1. Slow twitch (type I)

- smaller in diameter
- reddish color
- use aerobic resp. for ATP supply
- contain more mitochondria
-fire slowly, but take long to
fatigue.

2. Fast twitch (type IIA)

- large diameter
- white in color
- less mitochondria
- uses both anaerobic and aerobic
energy transfer

3. Fast twitch (type IIB/X)

- same physical characteristics as Type
IIA, but strictly uses the glycolytic
anaerobic system