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.
This is a simple indirect test that is used to estimate the predominant muscle fiber type-slow twitch or fast twitch. It is interesting for athletes to know the composition of their muscle fibers. If they are primarily a strength or speed athlete, they want fast twitch fibers.For endurance athletes, more slow twitch fibers is optimal. This test does not replace an actual muscle fiber composition test, which would be more accurate but involves an invasive muscle biopsy and more sophisticated analysis.1  purpose: to estimate the predominant muscle fiber type for any given muscle group.his test does not replace an actual muscle fiber composition test, which would be more accurate but involves an invasive muscle biopsy and more sophisticated analysis. 1  purpose: to estimate the predominant muscle fiber type for any given muscle group.