Muscle Fibers - Type IIA

Also known as:  Intermediate Muscle Fibers

Type IIA Muscle Fibers are a sub-type of Type II (Fast-Twitch) Muscle Fibers found in Skeletal Muscle.  Type IIA Muscle Fibers contain high amounts of Myoglobin;  they do not produce strong contractions and have minimal capacity for enlargement (Muscle Growth);  their numbers (in comparison to other types of Muscle Fibers) are low.