All Glossary Terms
Anatomy

Muscle Fiber Types

Different types of muscle fibers (Type I and Type II) with distinct properties.

Updated

Muscles contain two main fiber types: Type I (slow-twitch) and Type II (fast-twitch). Type I fibers are fatigue-resistant and suited for endurance. Type II fibers generate more force but fatigue quickly, suited for strength and power. The mix varies by individual and muscle, influencing optimal training.

Examples

  • Type I: endurance, slow to fatigue
  • Type II: power and strength
  • Ratio partly determined by genetics

Common questions

What is Muscle Fiber Types?

Different types of muscle fibers (Type I and Type II) with distinct properties. Muscles contain two main fiber types: Type I (slow-twitch) and Type II (fast-twitch).

What are examples of Muscle Fiber Types?

Type I: endurance, slow to fatigue; Type II: power and strength; Ratio partly determined by genetics.

Put it into practice

12-Week Muscle Building · £29

A 12-week, four-day hypertrophy plan in three phases, with a modest calorie surplus

Explore More Terms

Browse our complete fitness glossary with 266 terms.

View All Terms