Normal levels of creatinine in the blood are approximately 0.6 to 1.2 milligrams (mg) per deciliter (dL) in adult males and 0.5 to 1.1 milligrams per deciliter in adult females. Muscular young or middle-aged adults may have more creatinine in their blood than the norm for the general population.
Fiber Types and Skeletal Muscle Hypertrophy The force generated by a muscle is dependent on its size and the muscle fiber type composition. Skeletal muscle fibers are classified into two major categories; slow-twitch (Type 1) and fast-twitch fibers (Type II).
Type II muscle fibers, also called fast-twitch, are large muscle fibers used for lifting heavy loads. A weight lifter has an abundance of type II muscle fibers. Competitive sprinters also have plenty of type II muscle fibers in their large leg muscles, which are used to produce strong movements for a short time.