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. Long-duration cardio to burn fat without bulking up. This will avoid targeting the type of muscle fiber that makes muscle get big and bulky. Instead, long-duration cardio (e.g. long-distance running) will target a smaller muscle fiber that has very limited capacity for growth.