Sports Science Energy Systems PDF

**20.11.2024** **LO 5.1 Energy systems** **Lo: to develop an understanding of ATP and how it is used to create energy** Energy -- the ability to do work Systems -- a set of connected things Energy comes from food and the food is turned into ATP **ATP:** Adenosine Triphosphate **The three ener...

**20.11.2024** **LO 5.1 Energy systems** **Lo: to develop an understanding of ATP and how it is used to create energy** Energy -- the ability to do work Systems -- a set of connected things Energy comes from food and the food is turned into ATP **ATP:** Adenosine Triphosphate **The three energy systems:** - ATP-PC system -- this is used for short, powerful bursts of exercise, it lasts less than 10 seconds, and is high intensity, used for something like a 100-metre sprint. - Lactic acid system -- used for medium length exercise that causes that burning feeling, high intensity, lasts for about 30 seconds to 3 minutes, examples would be weightlifting, circuit training and the 400-metre race. - Aerobic system -- this is used for long distance exercise, lasts for 3 minutes up to an indefinite amount of time, low intensity, examples marathon, riding, swimming. The aerobic system is unlimited as it uses oxygen but it takes longer to warm up. So if you had a good supply of oxygen and fuel (food) you could run for as long as you could before you get injured. **25.11.2024** **The ATP-PC system** **Lo: To develop an understanding of ATP and how it is used to create energy** **Adenosine Tri-phosphate (ATP)** -- the only compound cells can take energy from **Adenosine Di-phosphate (ADP)** -- the compound produced after ATP releases its energy **Phosphocreatine (PC)** -- a compound used to resynthesize ATP, **sometimes wrote as creatine phosphate (CP)** **Exothermic** -- a reaction that releases energy and heat **Endothermic** -- a reaction that takes in and needs energy and heat **Energy** -- used to power the cells of the body **Where does energy come from**: - The energy we need comes from carbohydrate which is broken down into glucose. - If the glucose isn't needed immediately it is stored in the liver and muscles as glycogen. - Fats are broken down into free fatty acids - All of this must be converted into ATP before it can be used, as our cells can only run on/ use ATP To release energy -- an enzyme ATPase is released in and exothermic reaction and breaks down the bond. This only produces enough energy to last for **2 seconds**. This leaves ADP, phosphate molecules and energy. The amount of ATP that can be stored in the body is limited and this store can only last for 2 seconds. This means that the ADP must be resynthesized back into ATP. This happens in an endothermic reaction from a combination of three energy systems: - The ATP-PC system - The lactic acid system - The aerobic system **The ATP-PC system:** - Phosphocreatine (PC) is stored in the sarcoplasm of the muscle. - When the chemical bonds which join the PC together are broken down by the enzyme creatine kinase energy is released. - This energy is then used to resynthesis/re-make ATP so our body can use it. - From the breakdown of 1 PC molecule only 1 molecule of ATP can be resynthesized, we only have enough stored phosphocreatine for 8-10 seconds of activity. - There are no fatiguing by products - The energy source is stored in the muscles - The energy is provided immediately - Oxygen is not needed -- its anaerobic - Fewer chemical reactions involved **Disadvantages of the ATP-PC system:** - It only lasts up to 10 seconds - Only 1 ATP molecule is produced (ratio of resynthesis 1:1) - There are limited PC stores which cannot be greatly improved **28.11.2024** **The Lactic Acid system** **Lo: to develop an understanding of the Lactic acid system and how it produces energy.** The ATP system only lasts for around 10 seconds. So as PC stores run out the **Lactic** **acid** **system** then takes over. This starts with **anaerobic** **glycolysis** and takes place in the sarcoplasm of the muscles. **Glycogen** is then broken down into **pyruvic acid** using the enzyme **PFK (Phosphofructokinase).** Resynthesis 2 ATP molecules. As the physical activity is still at a high intensity, there is **insufficient** **oxygen** -- so the **pyruvic acid** is converted into lactic acid by the enzyme **LDH (Lactate dehydrogenase).** **Lactic acid** inhibits enzymes from working properly. **2.12.2024** **Energy systems** **Lo: to develop an understanding of aerobic energy systems and the three stages.** **Aerobic system:** - Can be called the 'oxidative system' - It breaks down glycogen, glucose and fats to provide energy - The aerobic system uses oxygen to completely break down one molecule of glucose into H2O and Co2 - This is done through the 3 complex stages Image preview The break down of **fats** is called beta oxidation Krebs cycle takes place in a mitochondria **Advantages and disadvantages of the aerobic system:** +-----------------------------------+-----------------------------------+ | Advantages | Disadvantage | +===================================+===================================+ | - Nearly limitless energy | - Takes time to transmission | | production if amount of fuel | into the system | | supplied stays the same | | | | - Only suited to low intensity | | - Very efficient energy | activity | | production, 36-38 ATP per | | | glycogen molecule | - Takes 20 minutes for your | | | body to break down fats | | - No harmful by products | | | | | | - Also uses fats and proteins | | +-----------------------------------+-----------------------------------+ **4.12.2024** **The energy continuum** **How intensity and duration of exercise determines which energy system is predominant** **\ The recovery process of each system:** - As you start to exercise, the demand for energy is very high, however, you can't get the energy quickly enough from the aerobic system. - Therefore, our body "borrows" energy (from muscle stores), to be paid back later either at rest or reduction in intensity or a game where there are bouts of high activity followed by low/no activity (a hockey game split into quarters with breaks in between) - The diagram shows how once exercise stops then oxygen debt can be fully repaid. **There are two parts of the EPOC:** - The **fast component;** Resynthesizing Phosphocreatine (PC). Creatine + phosphagen + energy (from aerobic system) = PC - This happens very quickly (around 3 mins). Which explains why you are able to take short breaks before sets in the gym. 50% can be resynthesized in 30 seconds and 75% in 60 seconds. - The **slow component:** This works with removing the lactic acid in one of 2 ways. - Converting it back into pyruvic acid, which in turn is converted into glucose and glycogen (the reversal of glycolysis) - Through the Cori cycle, where lactic acid goes into the liver to be converted into glycogen and returned to the muscles. - This means that lactic acid is not as negative as many think -- its actually used as an important energy source. - This is a slow process, taking 2 or more hours depending on the intensity of activity and if a cool down is completed. - The majority of lactic acid is oxidised into CO2 and H2O by converting into pyruvic acid, passing through the mitochondria ti be used by the Krebs cycle and the ETC. - Cool downs can substantially reduce the time taken to remove lactic acid. **10 marker: a marathon runner relies predominantly on the aerobic system during a race. Describe the aerobic system and explain why it provides the majority of energy needed during the race.** - The breakdown of ATP produces energy - Uses oxygen to enable energy production. Uses fats, carbohydrates and protein - There are three stages of this system: - **Glycolysis**, this takes place in the sarcoplasm of the muscle, then the glucose is converted into glycogen then pyruvic acid. Oxygen is available and therefore pyruvate doesn't turn into lactic acid. 2 ATP are produced. - Pyruvate is catalysed Co enzyme A and acetyl co-enzyme A/CoA is produced. - **Krebs** **cycle** takes place in the mitochondria. Acetyl CoA combines with oxaloacetic acid to form citric acid. 2 ATP produced. Co2 is produced and hydrogen ions. - **Electron** **transport chain** -- 32 -- 34 ATP produced. In total 36-38 are produced. - High energy yield. - Low intensity, long duration. - Lactic acid is not produced so the athlete won't fatigue. - ATP-PC would be used at the very start and for the sprint finish at the end.