According to the Encyclopedia Dictionary of Biology, voluntary muscles, also known as striated, skeletal or striped muscles, refer to muscles that are within a person’s control and are generally attached to the skeleton. An individual muscle is composed of bundles of long muscle fibers. A strong connective tissue sheath covers the entire muscle, which is attached to a bone at each end through inextensible tendons.
The Encyclopedia Dictionary of Biology further elaborates that smaller fibers called myofibrils run through each muscle fiber. The myofibrils have alternate light and dark bands that contain protein filaments that give the muscle a contractile ability and a striped appearance under the microscope.
According to the BBC, voluntary muscles make the body move. They consist of slow twitch and fast twitch fibers. Slow twitch fibers contract slowly while using oxygen well and going on continuously for a long time. On the other hand, fast twitch fibers contract rapidly, but they do not use oxygen well and tire fast. The BBC notes that endurance athletes typically have more slow twitch fibers whereas sprinters have more fast twitch fibers.
KidsHealth explains that skeletal muscles are voluntary muscles and they are part of the musculoskeletal system, which is comprised of the muscles and the skeleton. The skeletal muscles work together with the bones to provide power and strength to the body. KidsHealth says that some of the biggest and most powerful muscles are located in the back, near the spine.