Energy Systems Flashcards
What are the three energy systems where fuels (food, phosphocreatine) are converted to energy
Energy systems:
ATP-PC
Anaerobic - glycolytic (lactic acid)
Aerobic
What is the during of the ATP-PC system
1-3 seconds can last up to 10 seconds
What is the duration of Anaerobic - glycolytic
What is the duration of the aerobic energy system
30 s and over - long periods of time
What is the intensity of ATP-PC energy system
Maximum intensity
What is the intensity of Anaerobic - glycolytic energy system
High
With recovery time
Intensity for aerobic energy systems
Low
How do the energy systems work when exercising
They overlap - never work independently
It’s the contribution of each system that varies
What is the pathway of how energy is created in the ATP system
There is 1 A and 3 P
An enzyme breaks off a P to create ADP which releases energy = ATP = ADP + P
Phosphocreatine makes a reaction which causes energy = P + C + Energy
This causes Energy —— ADP + P which leads to ATP being created
What is the site of reaction - controlling enzyme for the ATP PC system
Sarcoplasm
What is the ATP yield in the ATP PC system
1:1
Advantages of the ATP PC system
ATP can be re synthesised rapidly using the ATP PC system
Phosphocreatine stores can be re synthesised quickly
There are no fatiguing by products
It is possible to extend the time the ATP PC system can be utilised through the use of creatine supplementation
Disadvantages of ATP PC system
Limited supply of phosphocreatine in the muscle cell, only lasts for 10s
Only 1 mole of ATP can be re synthesised for every mole of PC
PC re synthesis can only take place in the presence of oxygen (when intensity is reduced
How do Hydrogen Ions effect us in the anaerobic glycolytic system
The accumulation of Hydrogen Ions:
Hydrogen ions are a by product of the lactic acid system (anaerobic glycolysis). H+ cause the muscle pH to drop (become more acidic). This inhibits the glycolytic enzyme and makes contractions difficult
Fuel source for anaerobic glycolysis system
Glycogen
The amount of ATP produced in anaerobic glycolytic system
Small amounts
By products of the anaerobic glycolytic system
Lactic acid, H+ ions, ADP
Advantages of anaerobic glycolytic system
No delay for O2
ATP can be re-synthesised quickly due to few chemical reactions
Can be used for high intensities - sprint finishes
Due to no oxygen, lactic acid can be converted back to the liver glycogen or used as fuel through oxidation into carbon dioxide and water
Disadvantages of anaerobic glycolytic system
Lactic acid as the by product. The accumulation de natures enzymes prevents an increase rate of chemical reaction
Only a small amount of energy can be released from glycogen under anaerobic conditions
Anaerobic glycolytic system chemical pathway
Glycogen
|
|
|
Glucose
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|- - PFK - 2ATP
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Pyruvate —- Lactic acid
What is the site of the anaerobic glycolytic system
Sarcoplasm
Enzyme for anaerobic glycolytic system
PFK
Enzyme for anaerobic glycolytic system
PFK
Yield for anaerobic glycolytic system
1:2
What is stage 1 in the aerobic energy system
Glycolysis - Glucose is broken down into pyruvic acid —- 2 ATP formed
Pyruvic acid is oxidised and Coenzyme A carries it into the Krebs cycle
What is stage 2 of the aerobic energy system
Stage 2: In the mitochondria matrix
Kerb cycle - The 2 acetyl groups diffuse into the matrix of the mitochondria.
The acetyl groups combine with oxaloacetic acid to form citric acid
Hydrogen is removed from the citric acid by ‘oxidative carboxylation’
Produces C,H and 2 ATP molecules
What is stage 3 of the aerobic energy cycle
Electron transport chain:
Hydrogen splits into H ions and H electrons both are charged with potential energy
H ions are oxidised to form water while the electrons provide enough energy to resynthesises 34 ATP
Advantages of the aerobic system
More ATP can be produced - up to 38 molecules
There are no fatiguing by products
Lots of glycogen and triglyceride stores so exercise can last a long time
Disadvantages of the aerobic system
Complicated systems - can’t be used straight away
O2 becomes available glycogen + fatty acids completely broken down
Fatty acids transportation to muscles is low and requires more O2
What is beta oxidation
Fatty acids undergo a process called beta oxidation
They are converted into acetyl coenzyme A which is an entry molecule into the kerb cycle
It then follows the same cycle as glycogen
More ATP can be produced from a molecule of fatty acids than one molecule of glucose
This is why long duration, low intensity exercise, fatty acids will be predominant energy source but depends on fitness of performer
What is VO2 max
The maximum volume of oxygen that can be taken up by the muscles per minute
What is sub maximal oxygen deficit
When there is not enough oxygen available at the start of exercise to provide all the energy (ATP) aerobically
Oxygen deficit = how much effort was anaerobic
Draw and label a graph that illustrates oxygen consumption during exercise and recovery
Know the oxygen deficit and steady state vo2 on a diagram
Know the different graphs for maximal and submaximal oxygen deficit.
What is maximal accumulated oxygen deficit (MAOD)
It gives an indication of the athletes anaerobic capacity
What is EPOC
Regaining oxygen after exercise
Reoxygenation of blood and myoglobin
Breakdown of lactate in blood
Resynthesis of glycogen from lactate (stored in liver)
2 components
What is the fast component of EPOC
2 - 3 minutes following the event
Need 1-4 litres of extra O2 to replenish ATP PC
50% restored in 30s
Replenishes all myoglobin stores of O2
What is the function of the slow component in EPOC
Removal of lactic acid
Maintenance of ventilation
Maintenance of circulation
Maintenance of body temperature
Requires 5-8 l of O2 can take minutes up to hours
Implications of recover on training, how can we use EPOC to help athletes
Warm up : An early increase in O2 delivery will minimise the O2 deficit
Active recovery/cool down : This increase in O2 delivery to the tissues and so speeds up fast and slow components of EPOC
Specificity of training: through specific training the athletes body will learn to recover quicker
Strategies: Us of time outs and certain tactics allow for recover during certain sports
Nutrition: Effective diet strategies before, during and after activity can delay fatigue and so speed up recovery
What causes fatigue
Depletion of ATP -PC stores e.g 100m sprint
Myoglobin has lost all its O2
Glucose and glycogen depletion (2 or more hours of work marathon)
High accumulation of lactic acid in muscles 400m sprinter
What is obla
OBLA and lactate threshold are the same thing- they are just different ways to measure lactate
Obla occurs around 4 mol/L lactate. It gives an indication of endurance levels.
Trained individuals can work at a higher intensity
What is lactate threshold
Is expressed as VO2 max. It occurs at 2 mmol/L above resting levels - so around 3-4mmol/L
Average performers have a lactate threshold of 50-60% VO2 max
We train at a level below lactate and fatigue so performance doesn’t deteriorate
The fitter we are the higher lactate threshold,d as a percentage of our VO2 max so we work harder
What is the difference between average performers and elite ones when comparing changes in lactate and VO2 max
Elite performers have higher vo2 max
Elite performers produce less lactate at higher intensities
Lactate threshold occurs at a higher percentage in elite athletes
Factors affecting the rate of lactate accumulation
Exercise intensity
Muscle fibre types slow twitch fibres produce less lactate
Rate of blood lactate removal, can be improved with training
The respiratory exchange ratio
Fitness of performer, fitter athletes have delayed obla
Why elite sprinters have better anaerobic endurance than non elite sprinters
Better at buffering, increase rate of lactate removal
Higher tolerance of lactate means they can work at higher intensities for longer
Muscles have adapted to training, higher capillary density and more myoglobin
Muscles have adapted to training, greater number and size of mitochondria
Factors that affect our ability to use O2
Physiological:
Increase stroke volume
Lifestyle
Body composition
Training e.g continuous fartlek, aerobic, interval ect
Genetics
Gender
The older you are the lower your vo2 max
Structural and physiological changes that lead to an improvement in VO2 max
Cardiac output
Reduced body fat - VO2 max decreases as body fat increases
Increased tolerance to lactate
increased cardiac hypertrophy
Greater HR range
Increased surface area of alveoli
Less O2 being used for heart muscle so more for skeletal muscles
Increased number and size of mitochondria
Increased stores of glycogen
Increased capillaries around the working muscles
Increased myoglobin content
Measurements of energy expenditure
Indirect calorimetry
Lactate sampling
VO2 max tests
RER (respiratory exchange ratio)
What is lactate sampling
taking blood samples. Lactate sampling involves measuring the level of lactate in the blood stream
Measures OBLA / lactate threshold
Testing is usually done during training e.g. games players using a pin prick
Ensures training is at the correct intensity / monitor improvements over time.
Why do athletes use lactate sampling
Endurance athletes may use lactate sampling because if they can establish their OBLA point, as a physiological measure this would dictate the speed they could run /swim/cycle (optimal speed).
Training would therefore be designed just below their OBLA.
Portable handheld device easy to use and administer
Gives immediate results to the performer
Games players would use this to inform training intensities as they try and improve their buffering system and tolerance to lactic acid.
Must be done regularly
Can be painful
What’s respiratory exchange ratio (RER)
RER is a physiological parameter that represents the ratio of carbon dioxide production (VCO2) to oxygen consumption (VO2) during metabolism. Mathematically, it is expressed as:
RER= VCO2 / VO2
indicating whether the body is predominantly using carbohydrates, fats, or a mix of both for fuel.
Why sports people use respiratory exchange ratio RER
Optimizing Fueling Strategies: Athletes can use RER measurements to tailor their nutrition plans. For example, during endurance activities, understanding when the body transitions from fat to carbohydrate metabolism can help athletes time their carbohydrate intake to sustain energy levels.
Training Intensity and Adaptation: Monitoring RER during training sessions allows athletes and coaches to assess the intensity at which the body switches between fuel sources. This information can be used to design training programs that target specific metabolic adaptations.
Individualized Training: Different athletes may have different RER responses to exercise.
Pros of using Respiratory exchange ratio
Precision in Nutritional Planning: RER provides insights into the specific macronutrients being utilized, allowing for precise nutritional planning to meet energy needs.
Training Optimization: Athletes can optimize their training programs by understanding how their body uses different fuel sources at various exercise intensities.
Individualization: RER can be used to tailor nutrition and training plans based on an individual athlete’s metabolic responses.
Cons of respiratory exchange ratio
Equipment and Expertise: Measurement of RER requires specialized equipment, such as a metabolic cart, and expertise in conducting indirect calorimetry. This can be a limitation in certain settings.
Invasive Techniques: Some methods of measuring RER may require wearing a mask or using a mouthpiece, which may affect the comfort and natural breathing patterns of athletes.
Variable Response: RER can be influenced by factors such as diet, fitness level, and environmental conditions. Interpreting RER values requires considering these factors for accurate insights.
What is VO2 max testing
VO2 max testing is a progressive test carried out on a treadmill or similar cardiovascular machine.
It is used to calculate the maximal volume of oxygen that can be consumed per unit of time and is usually measured in litres per minute/ml.kg.min−1. It involves use of gas analysis.
Why do elite athletes use vo2 max testing / why not
They can then plan a training programme to increase their VO2 max which would be monitored regularly.
Bleep tests and Coopers runs can be done easily but rely on the athletes motivation. You go to exhaustion which is difficult and can be unreliable.
The gas analysis requires equipment and data collection which may be difficult to access.
A endurance athletes and games players may also like to use lactate sampling because if they can establish their OBLA point, as a physiological measure this would dictate the speed they could run (optimal speed).
Training would therefore be designed just below their OBLA. A marathon runner could compare their OBLA point as a percentage of VO2 max to try to increase this percentage through training.
