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.
There are three ways a muscle fiber can be activated. Two allow for movement in the muscle and one simply creates tension, without joint movement. The three contraction types include: Concentric Muscle Contraction (shortening) - In weight training, this is the lifting phase of an exercise.