Muscle is soft, fibrous tissue in a human or animal that has the ability to contract, producing force that can result in movement, especially around a joint.
The term 'muscle' is generally considered to have arisen from the scientific name for the common mouse, Mus musculus, although the reasoning is obscure.
Muscles control posture and movement of an organism, including contraction of internal organs, such as the the heart and digestive system muscle.
The Nature of Muscle
- 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 muscle 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.
Interesting Facts About Muscle
- The largest muscle is the gluteus maximus of the buttock. This is a big bulky muscle.
- The longest is the sartorius, which winds from the knee to the hip on the inside of the leg
- The strongest may be the masseter muscle of the jaw. Some say the rectus femoris of the thigh or the gluteus maximus. This is difficult to measure.
- The smallest is the stapedius of the inner ear. At five hundredths of an inch (1.27 millimeters) this muscle helps conduct sound vibrations.
- The broadest is the latissimus dorsi of the lower back, which has the greatest external muscle area.
Building and Maintaining Muscle Size and Definition
To enhance and maintain muscle size and shape, you need several things:
- A balanced nutrition program that supports the maintenance of low body fat, as well as sufficient protein to build muscle when worked hard.
- An exercise program that complements your nutrition program by helping you maintain low body fat and increase muscle size. This usually requires some aerobic exercise in addition to a weight training program.
- A muscle-building program that targets the muscle size and definition of all body parts.
- An ongoing commitment to training, especially as you age.
You don’t have to reach the level of a competition bodybuilder – man or woman. Well-developed muscles and low body fat are good for fitness, health, self-esteem and personal image. However, it does mean low body fat, a flat stomach, well-shaped bottom and good looking arms, shoulders and legs.