A+P - energy systems.

• E5.

  Energy Systems in Combination.

  • During exercise the body does not switch from one system to another- energy at any time is derived from all three systems​
  • However, emphasis changes depending on the intensity of the activity relative to the efficiency of your aerobic fitness i.e. your ability to deliver and utilise oxygen
• E5.

  Energy Systems in Combination.

  1. The muscle cells burn off the ATP they already contain in about 3 seconds​
  2. The phosphocreatine (PC) system kicks in and supplies energy for 8-10 seconds. This would be the major energy system used by the muscles of a 100 metre sprinter or a weightlifter, where rapid acceleration, short duration exercise occurs​
• E5.

  Energy Systems in Combination.

  3. If exercise continues, the lactic acid energy system kicks in. This occurs in short distance exercises such as 200 or 400 metre runs or 100m swims​.

  4. If exercise continues, the aerobic system takes over. This occurs in endurance events such as an 800 metre run, marathon run etc.​
• E5.

  Adaptations of the Energy Systems to Exercise.

  • Long term exercise will allow the body’s energy systems to adapt to the physical demands of exercise​
  • This means that by following an exercise programme it is possible to train each energy system so that you can perform for longer and at increasingly harder intensities
• E5.

  Adaptations of the Energy Systems to Exercise.

  Increased Creatine Stores.

  • Short-duration, interval training sessions using high intensity exercises will improve your ability to produce anaerobic energy​
  • Your body will adapt and be able to store more creatine in the muscles which will improve the ATP-PC system​
  • This will result in you being able to exercise anaerobically for longer using fast and powerful movements
• E5.

  Adaptations of the Energy Systems to Exercise.

  Increased Tolerance to Lactic Acid.

  • Anaerobic training stimulate the muscles to become better able to tolerate lactic acid and to clear it away more efficiently​
  • With endurance training the capillary network extends, allowing greater volumes of blood to supply the muscles with oxygen and nutrients​
  • The muscles are able to use more fat as a fuel source and become more efficient at using oxygen, increasing the body’s ability to work harder for longer without fatiguing​
  • The net result is an increase in the body’s maximal oxygen consumption​
• E5.

  Aerobic Energy Systems.

  • Long term exercise will improve the ability of the aerobic energy system to produce energy, as improvements in the cardiovascular system will allow for increased oxygen to be delivered which is needed to produce ATP aerobically ​
  • Likewise adaptations of the cardiovascular system will aid the removal of lactic acid through oxidisation
• E5.

  Aerobic Energy Systems.

  Increased Use of Fats as an Energy Source.

  • Fat is the primary energy source during low intensity exercise​
  • Fat combustion powers almost all exercise at approximately 25% of aerobic capacity (the maximum amount of oxygen that can be consumed during maximal exercise)​
  • Fat oxidation increases if exercise extends to long periods, as glycogen levels deplete​
• E5.

  Aerobic Energy Systems.

  Increased Use of Fats as an Energy Source.

  • When considering the effects of long term exercise, the trained athlete has a greater opportunity to burn fat as a fuel than a non trained athlete because they have a more efficient system of delivering oxygen to the working muscles, as well as a greater number of mitochondria
• E5.

  Aerobic Energy Systems.

  Increased Storage of Glycogen and Increased Numbers of Mitochondria.

  • Muscles increase their oxidative capacity with regular training​
  • This is achieved by an increase in the number of mitochondria within the muscle cells, an increase in the supply of ATP and an increase in the quantity of enzymes involved in respiration​
  • The ability of the muscles to store more glycogen is also increased, meaning that anaerobic glycolysis can last for longer
• E6.

  Additional Factors Affecting the Energy Systems.

  Diabetes.

  • Diabetes is a condition where the amount of glucose in your blood is too high​
  • This is known as type 1 diabetes​
  • It develops when glucose cannot enter the body’s cells to be used as fuel​
  • Insulin is the hormone produced by the pancreas that allows glucose to enter the body’s cells, where it is used as fuel for energy​
  • If you have diabetes, your body cannot make proper use of this glucose so it builds up in the blood and cannot be used as efficiently 
• E6.

  Additional Factors Affecting the Energy Systems.

  Hypoglycaemic Attack.

  • Hypoglycaemia is an abnormally low level of glucose in the blood​
  • When your glucose level is too low, your body does not have enough energy to carry out its activities​
  • Hypoglycaemia mainly occurs if someone with diabetes takes too much insulin, misses a meal or exercises too hard​
  • Typical early warning signs are feeling hungry, trembling or shakiness, and sweating​
  • Additional symptoms include confusion, and you may have difficulty concentrating- and even may become unconscious
• E6.

  Additional Factors Affecting the Energy Systems.

  Children’s Lack of a Lactate System.

  • Although we all possess the same body’s systems, a child’s body systems are still growing and developing, with significant changes occurring during puberty​
  • One such area is the lactate energy system, which is not fully developed in children​
  • During high intensity exercise, lactic acid will build up in the muscles and, due to their developing cardiovascular system, it is more difficult for children to remove this waste product- therefore it is recommended that children exercise aerobically​