Red muscle fibers

White muscle fibers

1. They are slow & thin.
2. They contain a hemo protein pigment in large amount, so they are dark red.
3. myoglobin released large amount of o₂, so large amount of energy is available, that’s only they never get fatigued.
4. They have many mitochondria.  

1. They are fast & thick.
2. They have small amount of myoglobin, so they are white (light) in color.
3. myoglobin releases small amount of o₂ , so small amount of energy is available, that’s why, they easily get fatigued with work.
4. They have small amount of mitochondria.