Exercise Physiology: Theory and Application to Fitness and Performance 9th Edition by Scott Powers, Edward Howley

Exercise 4

Describe the mechanical and biochemical properties of human skeletal muscle fiber types.

Step 1 of 3

Based on the histochemical and biochemical properties, human skeletal muscles are divided into two categories as given below:

• Slow, type I fibers, also called slow twitch fibers

• Fast, type II biers, also called fast twitch fibers. Fast twitch fibers are further classified into two types

a. Type IIa fibers

b. Type IIx fibers

Muscles generally contain a combination of these two types of fibers. Exercise influences the composition of these two types of fibers in the muscle.