8.1: Energy Systems Flashcards
(48 cards)
1
Q
energy definition:
A
- constant supply so we can perform every day tasks such as tissue repair and body growth.
- as we exercise the body converts energy from food into energy for muscle contractions in order to order to provide movement such as running, catching and throwing.
2
Q
What does ATP stand for?
A
- adenosine triphosphate
3
Q
What is ATP?
A
- the only useable form of chemical energy in our body.
- carbs are broken down to release energy used to form ATP.
4
Q
Breakdown of ATP:
A
- ATPase is the enzyme used to break down ATP leaving adenosine di-phosphate (ADP) and an inorganic phosphate (Pi)
- ATP = ADP + Pi + energy
- ATP is fuelled by phosphocreatine which occurs in the muscles.
5
Q
What are the three energy systems?
A
- aerobic system
- APT-PC system
- anaerobic glycolytic system
6
Q
When are the systems used?
A
- low intensity and long duration: aerobic system
- high intensity and short duration: either anaerobic glycolytic system or ATP-PC system.
7
Q
What is the aerobic system?
A
- system breaks down glucose into carbon dioxide and water.
- complete oxidation can produce up to 38 molecules of ATP.
- fats (in form of fatty acids) and proteins (in form of amino acids) can also be broken down.
8
Q
What are the three stages of the aerobic system?
A
1) glycolysis
2) krebs cycle
3) electron transport chain
9
Q
What is glycolysis?
A
- takes place in sarcoplasm of muscle cell.
- breakdown of glucose to pyruvic acid.
- for every molecule of glucose, a net of two molecules of ATP is formed.
10
Q
What is krebs cycle?
A
- pyruvic acid is oxidised into two acetyl groups carried into the kreb cycle as by coenzyme A.
- occurs in the mitochondria.
- acetyl groups combine with oxaloaectic acid, forming citric acid.
- hydrogen is removed from the citric acid and the rearranged form of CA undergoes ‘oxidation carboxylation’ which simply means hydrogen and carbon are given off.
- carbon form CO2 which is transported to the lungs and hydrogen is taken to the electron transport chain.
11
Q
What is electron transport chain?
A
- hydrogen is carried to the electron transport chain by hydrogen carriers
- occurs in the cristae of mitochondria and hydrogen splits into hydrogen ions and electrons and are charged with potential energy.
- hydrogen ions are oxidised to form water while hydrogen ions provide energy to re-synthesise ATP.
- throughout this process 34 ATP are formed.
12
Q
What is beta oxidation?
A
- stored fat is broken in glycerol which is converted into acetyl coenzyme A, which is the only entry molecule for Krebs cycle.
13
Q
What are the advantages of aerobic system?
A
- more ATP produced: 36 ATP
- no fatiguing by-products (carbon dioxide and water)
- lots of glycogen and triglyceride stores so exercise can last for a long time.
14
Q
What are the disadvantages of aerobic system?
A
- complicated system so cannot be used straight away. Takes a while for enough oxygen to become available to meet demands of activity and ensure glucose and fatty acids are completely broken down.
- fatty acid transportation to muscles is low and also requires 15% more oxygen to be broke down than glycogen.
15
Q
What is ATP-PC system?
A
- re-synthesises ATP when the enzyme creatine kinase detects high levels of ADP. It breaks down phosphocreatine in the muscles to phosphate and creatine, releasing energy.
- this energy is then used to convert ADP to ATP in a coupled reaction.
16
Q
Advantages of ATP-PC system?
A
- can be re-synthesised rapidly using ATP-PC system
- phosphocreatine stores can be re-synthesised quickly ()30 secs = 50% replenishment, 3 mins = 100%)
- no fatiguing by-products
- possible to extend the time the ATP-PC system can be utilised through use of creatine supplementation.
17
Q
Disadvantages of ATP-PC system?
A
- only limited supply of phosphocreatine in the muscle cell, can last up to 8 seconds.
- only one mole of ATP can be re-synthesised for every mole of PC.
- PC re-synthesis can only take place in the presence of oxygen.
18
Q
What is the anaerobic glycolytic system?
A
- energy is supplied from breakdown of fuel glucose. This is supplied from the digestion of carbohydrates and is stored in the muscles and liver as glycogen.
- enzyme glycogen phosphorylase is activated to break down glycogen into glucose, which is broken down further to pyruvic acid by enzyme phosphofructokinase (PFK).
- takes place in the sarcoplasm of muscle cell without oxygen.
- pyruvic acid is then broken down into lactic acid by enzyme lactate dehydrogenase (LDH)
- 2 ATP are produced
- lasts up to 3 minutes but can peak at 45 seconds, e.g. 400m.
19
Q
Advantages of anaerobic glycolytic system:
A
- ATP can be re-synthesised quite quickly due to very few chemical reactions and lasts longer than ATP-PC system
- in the presence of oxygen, lactic acid can be converted back into lover glycogen or used as a fuel through oxidation into C02 and water.
- can be used for a sprint finish
20
Q
Disadvantages of anaerobic glycolytic system:
A
- lactic acid as by-product. accumulation leads to denaturing of enzymes and prevents them from increasing rate at which chemical reactions take place.
- only a small amount of energy can be released from glycogen under anaerobic conditions (5% as opposed to 95%)
21
Q
energy systems - slow twitch fibres:
A
- main pathway for ATP production is in the aerobic system
- produces the maximum amount of ATP available from each glucose molecule (up to 36 ATP)
- production of ATP is slow but these fibres are more endurance based so less likely to fatigue.
22
Q
energy systems - fast twitch fibres (11x):
A
- main pathways for ATP production is via lactate anaerobic system (during glycolysis)
- ATP production in absence of oxygen is not efficient - only two ATP produced per glucose molecule.
- production of ATP is fast but cannot last for long as these fibres have least resistance to muscle fatigue.
23
Q
What is lactate accumulation?
A
- anaerobic glycolytic system produces by-product of lactic acid.
- Lactic acid quickly breaks down, releasing hydrogen ions.
- combines with sodium ions or potassium ions to form lactate.
- as lactate accumulates in the muscles, more hydrogen ions are present.
- lactate slows down enzyme activity which affects the breakdown of glycogen causing muscle fatigue.
24
Q
Factors affecting rate of lactate accumulation:
A
- muscle fibre type
- rate of blood lactate removal
- fitness of a performer
25
Muscle fibre type:
- slow twitch fibres produce less lactate than fast twitch fibres.
- when slow twitch fibres use glycogen as a fuel glycogen can be broken down much more effectively and with little lactate production.
26
rate of blood lactate removal:
- if rate of lactate removal is equivalent to lactate production, the concentration of blood lactate remains constant.
- if lactate production increases, lactate will begin to accumulate in the blood until OBLA is reached.
27
factors affecting VO2 max:
- gender, age, lifestyle and physiological
28
gender:
- men generally have approximately 20% higher VO2 max than females.
29
age;
- as we get older, VO2 max declines as body systems become less efficient.
30
lifestyle:
- smoking, sedimentary lifestyle, poor diet and poor fitness can all recue VO2 max values.
31
physiological:
- increased levels of haemoglobin and RBC count
- increased number and size of mitochondria
- increased lactate tolerance.
32
fitness of the performer:
- someone who trains regularly will be in a better position to delay OBLA.
- increased numbers of mitochondria and myoglobin improve capacity for aerobic respiration and therefore avoid the use of anaerobic glycolytic system
33
What are different training methods?
- altitude training
- HIIT (high intensity interval training)
- Plyometrics
- Speed, agility, quickness (SAQ)
34
Altitude training definition:
- usually done at 2500m above sea level where the partial pressure of oxygen is lower.
35
What is altitude training?
- as altitude increases, partial pressure of oxygen drops.
- therefore there a reduction in diffusion gradient of o2 between air and lungs and between alveoli and blood.
- not as much oxygen is diffused into the blood so haemoglobin isn't fully saturated with oxygen lowering oxygen-carrying capacity off the blood.
- there is a reduction in performance as less O2 is delivered to muscles.
36
Advantages of altitude training:
- increase in number of red blood cells and the concentration of haemoglobin, an increase in capillarisation and EPO resulting in enhanced oxygen transport.
- can also lead to increase in lactate tolerance.
- altitude training is done to acclimatise players to low level of oxygen available in atmsophere.
37
Disadvantages of altitude training:
- when first experienced it is very hard for an athlete to train at the same intensity due to the reduction in partial pressure of oxygen. There can be a loss of fitness or detraining.
- altitude sickness is a possibility, can have a detrimental effect on a training programme.
- benefits gained may be lost very quickly to return to sea level and body can only produce a certain amount of EPO.
- may result in psychological problems such as homesickness.
38
What is HIIT training?
- can be used for both aerobic and anaerobic training.
- periods of work are interspersed with recovery periods.
- involves short intervals of maximum intensity exercise followed by recovery interval of low to moderate intensity exercise.
- work period is anaerobic and recovery aerobic.
- HIIT improves fat burning potential, glucose metabolism and both aerobic and anaerobic endurance.
39
Plyometrics definition:
- involves repeated rapid stretching and contracting of muscles to increase muscle power.
40
What is plyometrics?
- involves high intensity explosive events such as hopping, depth jumping, medicine ball work and uses fast twitch fibres.
- works on the concept that muscles can generate more force if they have previously been stretched.
- consists of three phases
41
What are the three phases of plyometrics?
- eccentric phase or pre-loading
- amortisation phase
- concentric or muscle contraction phase
42
Phase one - eccentric phase:
- on landing, muscle performs an eccentric contraction where it lengthens under tension.
43
Phase two - amortisation phase
- time between eccentric and concentric muscle contractions.
- needs to be as short as possible so energy stored from concentric contraction is not lost.
A lot of the energy produced is lost as heat however some energy is stored.
44
Phase three - concentric/muscle contraction:
- uses the stored energy to increase force of contraction.
45
Plyometrics exercises - arms:
- press-ups with clap or through throwing and catching a medicine ball.
- triceps experiences a quick stretch on the landing or catching the medicine ball. This is followed by a concentric muscle action as triceps extends in upward phase of the press-up or execution of the throw.
46
Plyometrics exercises - legs:
involves a line of benches, boxes and hurdles where performer has to hop, jump and leap from one to the other.
- recovery occurs when walking back to start
47
What is SAQ?
- type of training that aims to improve multi-directional movement through developing the neuromuscular system.
- drills include zig-zag runs and foot ladders
- sometimes a ball is introduced to make it more specific by passing
- energy is provided anaerobically due to maximum force at high speed.
48
What is lactate accumulation?
- anaerobic glycolytic system produces by-product of lactic acid.
- Lactic acid quickly breaks down, releasing hydrogen ions.
- combines with sodium ions or potassium ions to form lactate.
- as lactate accumulates in the muscles, more hydrogen ions are present.
- lactate slows down enzyme activity which affects the breakdown of glycogen causing muscle fatigue.
