Muscled

Muscled is an adjective used to describe organisms or body parts that have well-developed muscle tissue. It is most commonly applied to humans and other animals with noticeable muscular development, though it can describe any animal whose skeletal musculature is prominent.

Biologically, muscle tissue consists of fibers that contract to produce movement, posture, and force. Skeletal muscles are the best-known component in this sense, while smooth and cardiac muscles operate in internal organs and the heart.

Muscle growth, or hypertrophy, occurs mainly through resistance training and adequate nutrition. Proteins provide building blocks; calories support size gains. Hormones such as testosterone, growth hormone, and insulin-like growth factor I influence protein synthesis. Genetic factors determine baseline muscle mass and the capacity for growth, while age and training history modify results.

In practice, muscled may describe a physique characterized by visible muscle definition, strength, and low body fat. In agriculture and meat production, the term can refer to livestock with heavy musculature, sometimes seen in breeds selected for increased yield. Mutations in the myostatin gene have produced exceptionally muscular phenotypes in some cattle; these cases raise considerations about meat quality and animal welfare.