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.
3. Fast twitch fibres (Type IIb): Fast twitch IIb fibres contract extremely rapidly, create very forceful muscle contractions and fatigue quickly. Fast twitch IIb fibres are also âwhite fibersâ but unlike IIa fibres they can only use anaerobic energy sources.