{"id":438,"date":"2019-03-11T19:07:07","date_gmt":"2019-03-11T19:07:07","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/sunyltnutrition\/?post_type=chapter&p=438"},"modified":"2019-04-15T13:44:22","modified_gmt":"2019-04-15T13:44:22","slug":"10-5-how-do-my-muscles-get-the-energy-to-perform-work","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/sunyltnutrition\/chapter\/10-5-how-do-my-muscles-get-the-energy-to-perform-work\/","title":{"raw":"10.5: How Do My Muscles Get The Energy To Perform Work?","rendered":"10.5: How Do My Muscles Get The Energy To Perform Work?"},"content":{"raw":"Although muscles and engines work in different ways, they both convert\u00a0chemical energy\u00a0into energy of motion. A motorbike engine uses the stored energy of petrol and converts it to\u00a0heat\u00a0and energy of motion (kinetic energy). Muscles use the stored chemical energy of food we eat and convert that to heat and energy of motion (kinetic\u00a0energy).\u00a0We need energy to enable growth and repair of tissues, to maintain body temperature and to fuel physical activity. Energy comes from foods rich in carbohydrate, protein and fat.\r\n
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Origins of the Energy for Muscle Contraction<\/h2>\r\nThe source of energy that is used to\u00a0power\u00a0the movement of\u00a0contraction\u00a0in working muscles is\u00a0adenosine triphosphate\u00a0(ATP) \u2013 the body\u2019s\u00a0biochemical\u00a0way to store and transport energy. However, ATP is not stored to a great extent in cells. So once\u00a0muscle\u00a0contraction starts, the making of more ATP must start quickly. Since ATP is so important, the muscle cells have several different ways to make it. These systems work together in phases. The three biochemical systems for producing ATP are, in\u00a0order:\r\n
    \r\n \t
  1. using creatine phosphate<\/li>\r\n \t
  2. using glycogen<\/li>\r\n \t
  3. aerobic\u00a0respiration.<\/li>\r\n<\/ol>\r\n
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    Creatine\u00a0 Phosphate (with oxygen)<\/h3>\r\nAll muscle cells have a little ATP within them that they can use immediately \u2013 but only enough to last for about 3 seconds! So all muscle cells contain a high-energy\u00a0compound\u00a0called\u00a0creatine phosphate\u00a0which is broken down to make more ATP quickly.\u00a0Creatine phosphate\u00a0<\/i>can supply the energy needs of a working muscle at a very high rate, but only for about 8\u201310 seconds.\r\n\r\n<\/div>\r\n
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    Glycogen (without oxygen)<\/h3>\r\nFortunately, muscles also have large stores of a\u00a0carbohydrate, called glycogen, which can be used to make ATP from\u00a0glucose. But this takes about 12 chemical reactions so it supplies energy more slowly than from creatine phosphate. It\u2019s still pretty rapid, though, and will produce enough energy to last about 90 seconds.\u00a0Oxygen\u00a0is not needed \u2013 this is great, because it takes the heart and lungs some time to get increased oxygen supply to the muscles. A by-product of making ATP without using oxygen is\u00a0lactic acid. You know when your muscles are building up\u00a0lactic acid\u00a0<\/i>because it causes tiredness and soreness \u2013 the stitch.\r\n\r\n<\/div>\r\n
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    Aerobic Respiration (with oxygen again)<\/h3>\r\nWithin two minutes of exercise, the body starts to supply working muscles with oxygen. When oxygen is present, aerobic respiration\u00a0can take place to break down the glucose for ATP. This glucose can come from several places:\r\n