The Muscular System And Its Functions
While most people associate muscles with strength, they do more than assist in lifting heavy objects. The 650 muscles in the body not only support movement — controlling walking, talking, sitting, standing, eating and other daily functions that people consciously perform — but also help to maintain posture and circulate blood and other substances throughout the body, among other functions.
Muscles are often associated with activities of the legs, arms and other appendages, but muscles also produce more subtle movements, such as facial expressions, eye movements and respiration, according to the National Institutes of Health
The Muscular System Broken Down
Muscle exists as 3 types: cardiac muscle, smooth muscle, and skeletal muscle. Skeletal muscle is the target of strength and conditioning training. Smooth muscle makes up blood vessels and certain organs.
Skeletal muscle makes up approximately 45% of total body weight.
Skeletal muscle attaches to two bones and crosses a joint between them.
Muscle cells are elongated and cylindrical in shape and are called fibers. Muscle cells and fibers are synonymous.
Muscles can contract and shorten, thus creating a pulling force on bones and the attachments to bones (tendons and ligaments)
Muscles are organs, which means they have more than one type of tissue. Muscle contains muscle and fibrous connective tissue (fascia).
Muscles also incorporate blood vessels and nerves.
The nerves process messages from the central nervous system to the muscle, triggering contraction. Blood vessels supply nutrients and the energy required for movement and remove waste products.
A motor unit consists of a motor neuron (nerve cell) and the muscle fibers that it controls. Motor units are often referenced in relation to muscle activation in weight training.
“Optimal conditions” mean that you are eating the right amount and the right kinds of food, AND you are training perfectly for muscle growth (which we’ll explain below). Proper sleep is also absolutely necessary.
This also means you are trying to thread the needle of eating JUST enough to build muscle, but not too much that you put on a lot of fat, too. Yeah, you could go full hulk mode (“dirty bulk”) and just eat anything and everything, maxing out your muscle building… but it’ll be buried under fat, which you’ll have to trim again and restart the cycle.
While it is certainly one effective way to gain muscle and strength, we more often recommend fiddling with your diet and training so you can find that sweet spot where you’re building muscle and not gaining too much fat.