Muscle Types

When scientists began to explore the different types of muscles, muscle fibers were categorized depending on their color -> Red and white muscle fibers. Because Red muscle fibers have more blood vessels and mitochondria, they appeared red and therefore were just called "red muscle fiber". The other type had a lower content of blood vessels and mitochondria appear white. White muscle fiber has the ability to grow up to four times bigger and contracts 2 to 3 times faster then red muscle fiber. That's why white muscle fiber is also called fast twitch muscle fiber and red fiber is also known as slow twitch muscle fiber. White (fast twitch) is what bodybuilders and short distance sprinters want to build. Red (slow twitch) which on the other hand can run on less energy, and that's why marathon runners and cyclists want white fiber.

Muscle Types

  • Type 1 (Red) slow oxidative
    This is the slowest muscle type - fatigue resistant muscle fiber. Contains a lot of myoglobin, mitochondria and blood vessels. ATP generated by the aerobic system (oxidative fibers) Split ATP slowly. Slow contraction and resistant to fatigue right muscle type for endurance sports such as marathon, triathlon, etc. Postural and high endurance muscles: Abdominals, forearm muscles etc.

  • Type 2a (Red) fast oxidative
    This is basically a a red muscle fiber again, but faster than red type 1. Type 2a is still quite fatigue resistant and contracts faster than type 1. Contains a lot of myoglobin, mitochondria and blood vessels. ATP generated by oxidation. Splits ATP a lot faster and contracts faster. This is the muscle type you would need for for middle distance runs, ice skating etc.

  • Type 2b (White) glycolic fiber - fast twitch B
    This is the fastest muscle fiber type and has less myoglobin, mitochondria and blood vessels. Contains large amount of glycogen, which means that sugar, or calories are stored very close to the source, because energy is used up quickly. ATP is split extremely fast. Fatigues very fast. Right muscle type for sprinting, bodybuilding and sports that involve explosive movements.

  1. List of Muscles, beginning with the "reddest"
    (highest percentage of slow twitch muscles fibers)
    - Human Heart
    - Forearms and Neck Muscles
    - Abdominals and Calf Muscles
    - Shoulders, Biceps, Triceps
    - Chest and Back Muscles
    - Hamstrings

    The more a muscle is used in daily life, the higher the percentage of red muscle fiber.


  • To train fast twitch muscle fibers, you don't have to move your weights fast. Training of fast twitch muscle fiber results from sets with 8 to 12 concentrated repetitions.
  • If you want to get fast, check my section about plyometric exercises.


  • The biggest bodybuilders like Ronnie Coleman, Kevin Levrone, Markus Ruehl etc, have a high amount of white muscle fibers. After all, only white muscle fibers have the ability to grow that big. What people often forget is that white muscle fiber is actually fast twitch muscle fiber. A lot of people think that bodybuilding makes slow. Nonsense!. Technically, bodybuilding makes you fast. The reasons why bodybuilders often seem slow are:
    • Most bodybuilders lack in coordination. Their muscles forget how to coordinate movements because the only go through he same motions all the time. If they would start working on sprinting techniques on the other hand, they would lose white muscle fiber and muscle mass in the training process.
    • They don't want to move fast when they are sore, and unfortunately they are sore most of the time.
    • You also need plyometric exercises to build up speed.
    • And last but not least, if you still don't believe me, visit youtube and search for "Kevin Levrone Sprint"