Discuss the relationship between muscle fiber type distribution and performance. How can physical training modify or change a person's fiber type distribution? As we have learned through our readings, the skeletal muscles of most bodies are made up primarily of three types of skeletal muscle fibers, but their proportion varies depending on what action the muscles perform. doing. For example, type I fibers such as neck, back and leg muscles have a higher proportion. According to Quinn (2014), type I muscles are slower and more effective, tend to fire much more slowly than fast-twitch fibers, and fatigue at a much slower rate. Therefore, slower twitch fibers are pronounced to help athletes run marathons and bike for hours. The muscles of the shoulders and arms are not always active but their use is intermittent; these muscles tend to have a greater amount of tension for use in throwing and lifting. These muscles have a combination of Type I and Type II B fibers. These fast-twitch fibers use anaerobic metabolism to create energy and are the "classic" fast-twitch muscle fibers that excel at producing quick, powerful bursts of speed. These muscles are used in events such as the 100-meter sprint, basketball, soccer, and football. Because this muscle fiber fires at such a high contraction rate, it will fatigue much faster and won't last long before needing to rest. On average, about 60% of people have a fast-twitch muscle fiber and 40% have a slow-twitch (type I) fiber. . There may be changes in fiber composition, but basically we all have three types of muscle fibers that need training (Kenney, 2011). If you read several studies, believe it or not, but current research shows that the nervous system has the ability to change the type of fiber... in the center of the paper ......that transport blood to the heart are the superior vena cava and inferior vena cava. They are called that because they are the veins of the heart. The superior is located near the top of the heart. The inferior lies beneath the superior (The Franklin Institute, 2014). According to Virtual Medical Center (2014) the primary function of blood is to act as transportation, provide protection to the body, and help regulate. Blood dissolves gases such as oxygen and carbon dioxide. Blood also carries vital nutrients throughout the body, such as micronutrients, fatty acids, and amino acids. Blood flow helps regulate body temperature. Blood also removes metabolic waste material. Red blood cells (RBCs) are transported throughout the body to aid the body's natural defenses, blood clotting, and antibody transport.