Our muscles process fuel in the form of chemical energy to produce power for physical performance. Although your body contains hundreds of muscles, there are only three types of muscles. The Choose...pulmonarycardiacskeletalsmooth muscles are bundles of parallel, striated fibers attached to your skeleton and are under conscious control. There are two types of muscle fibers that make up muscle cells – fast twitch and slow twitch. Slow twitch fibers Choose...cannot function in the presence of oxygencan maintain muscular activity for a prolonged periodexert considerable more force than FT bundlesnone of the above. During shorter, higher-intensity endurance events like a mile run or a 400-meter swim the body utilizes Choose...only ST fibersonly FT fibersboth ST and FT fibersit depends on the fitness level of the individual. Choose...GeneticsAgeSexFitness level determine an individual's percentage of slow twitch fibers and fast twitch fibers.

ATP supplies the energy for muscle fiber contraction and relaxation. To produce ATP your muscles use the ATP-CP energy system, lactic acid energy system, and the oxygen energy system. Muscles store enough ATP to sustain muscle movements for Choose...less than a second30 seconds1 minute3 minutes. The body also stores creatine phosphate to Choose...use for energy after ATP is used upyour muscles can convert to ATPconvert AMP to ATPconvert ATP to lactic acid. After 3 to 15 seconds your body has used up its entire ATP and CP stores. Using the anaerobic glycolysis system, also known as Choose...aerobic metabolismthe citric acid cyclethe oxygen energy systemthe lactic acid energy system, muscle cells can break down thousands of glucose molecules from stored muscle glycogen to form ATP. This process causes the muscle cell to become more acidic which Choose...inhibits further breakdown of glucosedecreases the fibers’ calcium-binding capacityimpairs enzyme functionall of the above. In comparison to the ATP-CP and the lactic acid energy system, the oxygen energy system Choose...produces a low amount of ATP at a fast rateproduces a high amount of ATP at a slow rateproduces a low amount of ATP at a slow rateproduces a high amount of ATP at a fast rate.