The Muscular System & Exercise

The muscular system is what makes it possible for the body to move, breathe and pump blood and oxygen to vital organs. Exercise is essential to keeping the muscular system healthy and strong, but not all exercise is created equal. There are different kinds of muscles and different kinds of exercise, all with different effects on each other.

  1. Types of Muscle

    • There are three different types of muscular tissue: cardiac muscle, smooth muscle and skeletal muscle. Cardiac muscle is found only in the heart, smooth muscle is found in the internal organs and blood vessels and skeletal muscle connects to the bones and allows for physical movement. For the most part, cardiac muscle and smooth muscle movement is involuntary, meaning no conscious thought is needed for it to do its job. Skeletal muscle is mostly voluntary, controlled by the brain based on what the person wants to do (walk, smile, eat).

    Types of Exercise

    • Exercises that are intense but short, like weight-lifting or sprinting, use fast-twitch muscle fibers and are anaerobic---meaning they use more oxygen than the body can provide and create an "oxygen debt." Lactic acid is a byproduct of anaerobic exercise and is what causes muscles to feel sore later.

      Exercises that are less intense but more long-lasting, like marathon running, are aerobic and use only what oxygen the body can provide so there is no oxygen debt and no lactic acid byproduct.

    Endurance

    • Although there are countless ways to work out, all forms of exercise fall into one of two categories: endurance or resistance. Endurance exercises train the muscles to last longer without getting tired---the muscles usually do not get much larger in size, but instead become longer, leaner and more efficient. Runners, cyclists and other long-distance athletes train extensively with endurance exercises.

    Resistance

    • Resistance exercises, also called strength training, contract the muscle, which causes tearing and rebuilding of individual muscle fibers and growth of the muscle as a whole. Resistance exercises are used by all kinds of athletes, but are perhaps most notable in bodybuilders.

    Internal Effects

    • Physical exercise strengthens the heart, blood vessels and overall cardiovascular health as well as improving organ health and strengthening operations like swallowing, digesting and breathing that depend on smooth muscle function.

    Tendons

    • Tendons connect skeletal muscle to the bones of the skeleton (not to be confused with ligaments, which connect bones to other bones). All healthy exercises, either endurance or resistance, strengthen tendons and makes the connection between the muscles and the bones more secure.