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.
To start with all skeletal muscles consist of three main fiber types. These fiber types are: 1) Slow twitch fibers- Responsible for the strength and endurance of a muscle. 2) Intermediate twitch fibers- Possess qualities of both slow and fast twitch fibers. 3) Fast twitch fibers- Responsible for the speed of muscular contraction.