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 type of muscle fiber is described as red to pink, has a intermediate rate of fatigue, has fast contraction, is aerobic and anaerobic, has a high myoglobin content, is second to be recruited for contraction and is associated with activities such as walking and sprinting.