Muscle Types 101
Exercise makes all of your muscles bigger, right? The simple answer is no, but why? There are three muscle types that comprise our bodies.
Skeletal or striated muscle is attached to bones and has many nuclei with each fiber. This type of muscle comprises about 40% of an adult’s body weight.
They are controlled by the central nervous system and are therefore under voluntary control. Examples of skeletal movements are lifting your arm or rotating your torso. You can build up these muscles through physical activity and proper nutrition.
Smooth muscle acts involuntarily and is controlled by the autonomic nervous system. It is found in the walls of hollow internal organs such as blood vessels and the bladder. It contracts slowly and rhythmically, and has only one nucleus
Cardiac muscle is found in the walls of the heart and shares characteristics of both skeletal and smooth. It is controlled by the autonomic nervous system, has one central nucleus, but is also striated (having streaks). The cardiac muscle contracts involuntarily but is strong and rhythmical. For most people it stays the same size, but it has been noted that the hearts of marathoners can grow up to 40% due to increased workload.
What is amazing is that these three muscle types work together to allow us to do everything – from breathing to hand-eye coordination tasks, and all movements in between.