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.
Types of muscle fibers. Skeletal muscle, the type that is responsible for moving our muscles when we run, is comprised of three different muscle fiber types, each with its own advantages, disadvantages, and specialty.
On the other hand, there are some indications that strength training programs of < 6 months in untrained subjects can lead to a shift within the sub-types of type II muscle fibers, from type IIX to type IIA muscle fibers, as measured by muscle fiber type proportion.