lean tissue definition
Lean Muscle Mass. Lean muscle is a concept related to lean body mass, which is the content of the body minus fat. Lean body mass is used to calculate basal metabolic rate.Lean muscle is less of a scientific term and more a term of art that refers to muscle that is independent of, and not obscured by, fat.uscle mass is the main goal of weightlifting and bodybuilding. Muscles not only provide strength and power, but can be a visible manifestation of health and an essential part of a well-toned physique when not obscured by a layer of fat.