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Lesson 5 - Energy Systems
Transcript of Lesson 5 - Energy Systems
Energy is produced Aerobically or Anaerobically via three energy systems
The human body has three metabolic energy systems: ATP-CP System
Lactic Acid System
These systems serve to resynthesize ATP (Adenosine Triphosphate), a molecule that promotes energy in the body.
So how can we tell which energy system is being used during an activity?
This all depends on the duration of the
exercise, how urgently energy is required, the intensity of the exercise,
and whether or not oxygen is present.
Aerobic Exercise: An exercise that is done with the presence of oxygen
Anaerobic Exercise: An exercise that is done without the presence of oxygen
Anaerobic vs. Aerobic
The Body's Energy Systems:
The ATP-CP system is activated with high intensity exercises (90-100% max heart rate) that are carried out over short periods of time. This is because it uses stored creatine phosphate to produce maximal power quickly. However, the CP reservoirs do not last long due to the intensity at which the system is activated.
Intensity Of system
Since this system uses maximal power it's energy is only able to last for 10-15 seconds, depending on the individual's prior fitness.
Once the CP reservoirs are depleted, the individual must rest from 3-5 minutes to allow the regeneration of ATP to take place.
-Throwing a baseball/softball as hard as you can
-Sprinting for 10-15 seconds
-Vertical jump as high as you can go
Fatigue is not typically experienced during the usage of the ATP-CP system. However, if an individual's creatine phosphate levels are not fully replenished, the ATP-CP system cannot perform to its full potential and the lactic acid system becomes the main source of ATP re-synthesis - thus causing fatiguing by-products.
Fatigue is often experienced after an exercise is finished, as the high intensity movements promote the breaking down and repairment of muscle fibers in and around the exercised area.
-Lifting the heaviest weight you can for
The Science of the
The equation that describes the ability for ATP to re-synthesize in the ATP-CP system is as follows:
ADP + CP ---> ATP + C
To describe this equation, a Creatine phosphate molecule donates one phospate to Adenosine diphosphate, thus creating Adenosine triphosphate.
This system is anaerobic because it takes place without the presence of oxygen. Also, the exercises in which the ATP-CP system supplies energy to are short bursts of high intensity movements.
Foods to Fuel The ATP-CP system
There are no significant food sources for this system as all of the energy that fuels ATP re-synthesis comes from the creatine phosphate stored inside the skeletal muscles.
One can increase their creatine and/or phosphate levels by eating more meats and taking creatine and/or phosphate supplements.
Training the ATP-CP System
An effective way to train this system includes short, very fast sprints on the treadmill, bike, or on foot, lasting anywhere from 5-15 seconds. In between repetitions the user should take a 3-5 minute brake, allowing for the regeneration of CP in the muscles, in order to prepare the body for the next sprint.
Lactic Acid System
Intensity of System
When an individual is competing in strenuous activity for longer than 15 seconds, the ATP-CP system is depleted causing the lactic acid system to be the main source of energy. This system specializes in extended periods of high intensity exercise, where the heart rate is 85% of it's maximum.
The lactic acid system is the main supplier of energy to the body for high-intensity exercise lasting between 30-180 seconds.
Examples of Lactic Acid Activities:
200-400 metre hurtle sprint
50 metre swim
200 metre sprint
Fatigue in the lactic acid system is most common for athletes, as many sports demand high outputs of energy for extended periods of time.
Fatigue is a result of lactic acid building up in an area under strenuous activity, and usually occurs in 2-3 minutes of maintained exertion.
The chemical reaction which creates this lactic acid is described as anaerobic glycolysis.
Through anaerobic glycolysis, carbohydrates in the form of either blood glucose (sugar) or muscle glycogen (the stored form of glucose) are broken down to form pyruvate.
For every one glucose molecule that is broken down to pyruvate, two useable molecules of ATP are produced.
Despite the low amount of ATP created through this chemical reaction, this system provides the second quickest way to resynthesize ATP (after ATP-CP system), allowing for quick energy to be available during extended periods of high-intensity exercise.
Once pyruvate is formed it has two potential fates:
-conversion to lactate
-conversion to acetyl coenzyme A, which enters the mitochondria for oxidation and production of more ATP
Lactate forms when the demand for oxygen is higher than the amount of oxygen present. Since there is no oxygen in anaerobic glycolysis, the chemical reactions that take place are not fully completed. Thus, due to the incomplete reaction, lactic acid is created as a by-product. This by-product is the cause for the 'burning' sensation many individuals experience during extended and intense activity.
Lactic Acid System
Fueling The Lactic
Furthermore, any exercise/movement that consists of maximum exertion of a muscle or group of muscles can develop the ATP-CP system.
The lactic acid system relies on an abundance of absorbed and stored glucose in order to provide instant energy. Glucose is found in carbohydrate-rich foods such as potatoes, pasta, and other whole grains. Natural sugar sources that contain carbohydrates include: dried fruits, fresh fruits, and honey. Synthetic/added sugar should not be eaten as it is highly processed and often comes in foods that lack nutritional value.
An effective way to train this system includes extended periods of fast sprints on the treadmill, bike, or on foot, lasting anywhere from 30-120 seconds. Between repetitions an active recovery (movement with decreased intensity) that is two times the length of exertion should be taken.
High Intensity Interval Active Recovery Interval
Ratio for duration of intervals:
This system is anaerobic like the ATP-CP system, because it takes place without the presence of oxygen. The high intensity of the lactic acid system means there is a higher demand for immediate energy- oxygen does not contribute quick enough to the re-synthesis of ATP therefore it is not present.
Anaerobic Versus Aerobic
The intensity of the aerobic system is slightly lower than the other two systems, as it takes place during activities that promote a heart rate between 70-85% of its maximum.
The aerobic system is activated with long duration exercises that demand a moderate amount of exertion to be carried out over an extended period of time. This system can be activated during activity that lasts anywhere from 5 minutes to numerous hours (depending on the activity and fitness of the participant).
10 kilometre run
10 kilometre bike
(without explosive sprints)
Why is it Aerobic?
The aerobic system is the only system that uses oxygen through the re-synthesizing of ATP. Due to the lower intensity level of an aerobic exercise there is less of a need for immediate energy. This allows oxygen to have enough time to contribute to the ATP re-synthesis stages. Despite this system delivering ATP slowly, it is incredibly powerful as oxygen contributes to the production of ample ATP molecules.
The aerobic energy system fatigues due to a few different factors. Firstly, the depletion of fuel sources - especially glucose - will lead to a feeling of fatigue or tiredness (however, the aerobic system is extremely versatile and has the ability to switch to another fuel source without stopping. The switch of fuel sources does however give the participant a momentarily increased feeling of fatigue, described as 'hitting the wall'). Another factor that causes fatigue is poor respiration, including the inability for muscles to absorb an adequate amount of oxygen, and the poor outtake of waste products such as carbon dioxide.
of The Aerobic System
When carbohydrates are the main food source, glucose and glycogen are broken down through glycolysis, and the resulting pyruvate is used to form acetyl-Coenzyme A. This acetyl-Coenzyme A then enters the Krebs cycle.
The Krebs Cycle
When acetyl-coenzyme A enters the Krebs cycle it is oxidized, and the extraction of high-energy electron carriers (NADH and FADH2) takes place. These electrons are then transported through the electron transport chain, where ATP and water are produced.
The aerobic system is the slowest system to contribute to the re-synthesis of ATP, however the ratio of produced ATP molecules to glucose molecules is outstanding.
The intricate chemical process that makes up the aerobic system allows for 36 molecules of ATP to be produced for every one molecule of glucose broken down (carbohydrate as food source).
Furthermore 129 molecules of ATP are produced from the oxidation of the free fatty acid palmitate (fat as food source).
With fat as a food source
Other than carbohydrates, fat is the other major food source for the aerobic system.
Fat is the largest store of energy in the body, and is stored as triglyceride in adipose tissue located underneath the skin and within skeletal muscles.
Prior to Fat Metabolism
Stored triglycerides are broken down into free fatty acids and glycerol through a process called lipolysis. These fatty acids are composed of a long chain of carbon atoms, and are transported to the mitochondria to be used to produce acetyl-coenzyme A.
The aerobic energy system uses blood glucose and glycogen (carbohydrates), and fat to fuel the re-synthesizing of ATP within the mitochondria of muscle cells.
Therefore there are two potential food sources:
With carbohydrates as a food-source
After the Production of acetyl-coenzyme A from either food source, fat metabolism and carbohydrate metabolism are relatively the same.
Despite fat's extensive production of ATP molecules, carbohydrates are still the body's preferred method of energy as the length of time it takes to convert carbohydrates to energy is much shorter than that of fat to energy.
Foods that are rich in carbohydrates and/or healthy fats are ideal for fueling the body before an aerobic activity.
Some examples of food that help increase carbohydrate levels are pasta, potatoes, and bread.
Two excellent sources of healthy fats are nuts and olive oil.
To train the aerobic system you should focus on increasing duration/repetition of a given exercise and decreasing intensity.
The aerobic system can be trained with both intervals and continuous exercise. For example, using the stationary bike or treadmill:
~60 minutes at 70-75% max HR
~2 x 15-20 minutes at 75-85% max HR (do not surpass the lactate threshold)
May the energy of Nelson Athletes be replenished at last.
Anaerobic or Aerobic?
Of using the ATP-CP system
The Science Of The ATP-CP System
The quickest energy system to break down CP to form ATP
Contains simple and short chemical reactions
Is not always available for use - once maximal force is exerted the CP must be recovered before next usage
Rate of ATP Production
Total Ability To Produce ATP
Adipose and intramuscular fat
An Overview of The Three Energy Systems
- Describe the three different energy systems and their use in sport and exercise activities (P7).
- Explain the three different energy systems and their use in sport and exercise activitie (M4).
- Analyse the three different energy systems and their use in sport and exercise activities (D2).
Assessment Activity 1.5
Produce a written report:
- describe the different energy systems and their use in sport and exercise activities.
- Consider the activity of running and examine the different energy systems and explain how they come into play at different intensities and durations of running activity.
- Using a wider variety of sport and exercise activities, analyse the different energy systems and explain their use in the sports you have chosen to examine.
Watch this video clip and note down any important information:
How to achieve