1
Q
Energy systems -
Response of energy systems to physical activity
A
- Anaerobic - adenosine triphosphate-creatine phosphate (ATP-CP)
- lactic acid
- Aerobic
2
Q
Rate of ATP production =
A
How quickly ATP is resynthesised
3
Q
Yield =
A
How much ATP is resynthesised
4
Q
ATP
A
A chemical compound called adenosine triphosphate (ATP) is responsible for producing energy for movement
When ATP is broken down energy is released
ATP —> ADP + Pi (inorganic)
5
Q
Fuels required for resynthesis of ATP
A
- energy is released during the breakdown of ATP in to Adenosine diphoshate (ADP) and third phosphate - represents the immediate source of energy that can be used by muscle cells to perform
- when the body is performing physical work it is converting chemical energy (ATP) produced by chemical reactions into mechanical energy (muscular contractions)
6
Q
What is ATP
A
- only a very small amount of ATP is stored within muscles, so ATP must continually be rebuilt / resynthesised so that the energy can be provided for longer periods of time
- ATP can be rebuilt / resynthesised from the breakdown of phosphate creatine (PC) or from the breakdown of macronutrients (carbohydrates, proteins and fats) from of diet
7
Q
ATP-CP energy system
A
An immediate energy system that does not require oxygen
Fuel: uses a combination of stored ATP + the stored creatine phosphate
Intensity: maximum efforts >95% max HR
Duration: short duration (fuel depleted after 10 secs)
Rate of resynthesis: very fast
Yield: low
8
Q
ATP-CP advantages and disadvantages
A
Advantages:
- high intensity exercises
- rate of resysnthesis
- stored in muscles
Disadvantages:
- low yield
- duration
9
Q
Anaerobic glycolysis system (lactic acid)
A
Relies on breakdown of glycogen, in the absence of oxygen, to produce energy
Fuel: carbohydrates
Intensity: 80-95% max HR
Duration: will take over as predominant system when ATP-CP system fatigues (PC stores depleted at around 5 - 10 secs) predominant 10-6- second events. Peak power is usually reached between 5-15 secs)
Rate of resynthesis: fast
Yield: low - medium - 2ATP
10
Q
Anaerobic glycolysis system advantages and disadvantages
A
Advantages:
- intensity
- rate
Disadvantages:
- lactic acid - cramps
- low yield
- slow recovery (if lactic acid present)
11
Q
Glycolysis
A
Takes place in the cytoplasm, where the enzymes required are present
Glycolysis is to destroy or break down glucose
Because oxygen is not present, the glycogen is not totally broken down and a by-product called lactic acid (lactate + hydrogen ions) is formed
12
Q
Lactic acid
A
Use of the anaerobic glycolysis system results in the production of lactic acid.
13
Q
What happens when we accumulate lactic acid?
A
- Lactate purely serves as an indicator that the body is no longer working aerobically. It also represents the accusation of Hydrogen+ ions
- Although 80% of lactate diffuses from the muscles & transported back to the liver for conversion to glucose or glycogen some hydrogen ions (H+) accumulate in muscle tissue
- An increase in lactate levels means pH levels are dropping (a pH level of 7 indicates neutral - less than 7 means your muscles are becoming acidic) which decreases the activity of enzymes which break down glycogen
- Contracting muscles don’t like acid, so when pH levels drop, the stop working as a feedback mechanism to prevent injury. As a result, the anaerobic glycolysis pathway is compromised and exercise intensity must be reduced
14
Q
Aerobic system (fuel, …
A
Fuel: carbohydrates, fat and protein (depending on intensity, duration)
Intensity: during rest and at sub-maximal intensities <80% HR max
Duration: gradual increase in contribution as O2 becomes available. Predominant energy after 30-60sec ((2 min <) depending on intensity)
Rate of Resynthesis: slow
Yield: very high (36 -38 ATP)
15
Q
Aerobic system advantages and disadvantages
A
Advantages:
- high yield
- longer duration
- no by products that effects fatigue
Disadvantages:
- low intensity
- slow rate of resynthesis
16
Q
Aerobic glycolysis
A
The breakdown of glycogen in the presence of oxygen to produce energy, carbon dioxide, water and heat
Once O2 becomes available to the muscle cell a different chemical reaction known as aerobic glycolysis takes place
17
Q
The aerobic system takes a while to get going because a number of processes need to occur:
A
- lungs work harder to bring in more O2
- heart pumps harder to transport O2 rich blood to the muscles
- arteries expand to increase blood flow
18
Q
Aerobic system (2)
A
This system has the greatest capacity to produce ATP but is the slowest to do so (high yield but low rate)
The fuel source used by the aerobic system (carbohydrates and fats) depends on the intensity and ration of the activity
- Carbohydrates for the first 90 minutes then fats up till 4 hours
- CHO are the preferred energy source during high intensity exercise as fats can produce more ATP than CHO but they require more oxygen to produce an equivalent amount of ATP
19
Q
Steady state exercise
A
- Oxygen consumption rises sharply during first minutes of exercise
- This consumption begins to plateau between 3-4 minutes and will remain stable for the duration of exercise
- This means there is a balance between energy required by working muscles and ATP produced by the aerobic pathway
- This is referred to as Steady State “exercise”
20
Q
Oxygen deficit
A
- When excessive commences, O2 consumption does not reach “steady state” plateau immediately
- Oxygen deficit is the state in which there is a discrepancy (shortfall- (lack)) between oxygen supply and demand and the oxygen required to meet the energy requirements of the activity
- Energy used during O2 deficit period is supplied through anaerobic pathways
- Endurance-trained athletes reach steady state more rapidly, with smaller oxygen deficit
The oxygen deficit occurs because the respiratory and circulatory systems take some time to adjust to the new oxygen demand and, consequently, the amount supplied lags behind the amount needed
Oxygen deficit = oxygen consumption, O2 usage
- what your breathing in compared to what your body’s
21
Q
The bodies systems will adjustments to increase oxygen supply.
A
- increased respiratory frequency. - breathes
- increased tidal volume. - air per breathe
- increased heart rate
- increased stroke volume. - blood per beat
22
Q
EPOC stands for
A
Excess post-exercise oxygen consumption
(Oxygen debt)
23
Q
EPOC
A
EPOC is the amount of oxygen consumed during the recovery period (after the end of the activity).
It’s an increased rate of oxygen consumption above that is required during rest
Oxygen can be viewed as the ‘currency’ the body uses in order to ‘purchase’ (resynthesise) ATP.
In other words, oxygen must be used in order for ATP to be produced.
After the cessation of exercise, oxygen uptake or consumption does not immediately return to resting levels, despite the fact that the demand from ATP resynthsis decreases dramatically. Rather, oxygen consumption remains temporarily elevated. This elevated oxygen consumption, which exceed that normally experienced at rest, is referred to as excess post-exercise oxygen consumption (EPOC)
24
Q
The purpose of EPOC is to:
A
- replenish ATP-CP stores
- removes lactic acid
- replacing depleted oxygen stores in body
- supply oxygen to heart and respiratory muscles-still active
- supply oxygen to body tissues to be used because of increased body temperature resulting from exercise
25
Food fuels v chemical fuels
Energy from the breakdown of PC or the stored forms of CHO, fats and protein are used to re-join ADP & inorganic phosphate (Pi) to resynthesise ATP
26
Carbohydrates
- broken down into glucose for blood transportation
- stored as glycogen in the muscles & liver
- carbohydrates (sugars & starches, in foods such as fruit, cereal, bread, pasta & vegetables) are the body’s preferred source of fuel, particularly during exercise
27
Glycemic Index (GI)
Ranking of carbohydrates based on their immediate effect on blood glucose (blood sugar) levels.
Measured on a scale of -100
28
Low GI foods - food
- apples
- lentils
- kidney beans
- peanuts
- navy beans
- sausages
29
Moderate GI foods - food
- corn
- peas
- white pasta
- sweet potatoes
- oranges
- oatmeal
30
High GI foods - food
- pure glucose which has a GI of 100
- honey
- white bread
- white rice
- gel shot
- hot chips
31
High GI foods
- break down quickly during digestion - therefore have immediate effect on increasing blood sugar levels
- best consumed during and immediately after the event
32
High GI foods - during exercise
Rapid absorption and release of energy into bloodstream provides opportunity to top up glycogen stores, helping to delay the depletion of glycogen stores
33
High GI foods - immediately after exercise ( within 30 mins)
Immediately after exercise muscles are most responsive to topping up their fuel supplies, therefore it’s GI foods need to be consumed within 30 minutes of the activity finishing
34
Low GI foods
- break down slowly during digestion resulting in a slow release of glucose into the blood stream
- best consumed as part of the pre-event meal and after the event to replenish supplies
35
Low GI foods - Pre-event meal (1-4hrs prior)
Slower release of glycogen into bloodstream helps keeps blood glucose levels topping up prior to race
36
Low GI foods - After exercise (1-24hrs post exercise)
Assists with repletion of muscles and liver glycogen stores in the 24hr post exercise
37
Rebound hypoglycaemia
- athletes must be careful they don’t consume high GI foods 30-120min prior to event as it may cause rebound hypoglycaemia
- immediately after eating CHO, there is a rise in blood sugar levels resulting in the hormone insulin being released into the blood and lowering blood sugar levels
- when an athlete consumes high GI foods just prior to physical activity, we see a rapid rise in blood sugar levels causing an overshoot in insulin release
- this insignificant reduces blood sugar levels which impairs CNS functioning during exercise causing a negative effect on performance
38
Carbohydrate loading
Nutritional intervention aimed at delaying the depletion of glycogen stores. It occurs when the athlete increases the amount of CHO consumed prior to competition with the aim being to store extra glycogen in the liver and muscles. There are two main methods to load
During exercise, CHO stores become depleted, causing an increase in the use of fats for energy
Fats have a high oxygen cost than CHO, therefore the body must reduce exercise intensity
39
1 day method - carb loading
- consume approximately 8-10g/kg body weight of carbohydrates the day before competition (approx 700g stored in muscle and liver)
This is equivalent to eating almost 3 loaves of bread in 1 day - you need to use supplements!!
- tapering or reducing training load is required to spare muscle glycogen stores
40
3 day method - carb loading
- consume approximately 7-8g/kg body weight of carbohydrates for 3 days leading up to competition (approx 700g stored in the muscle and liver)
- players can still exercise, however there is significant tapering occurring leading up to competition so as to not deplete glycogen stores
- 3 day method is not suitable for sports which require athletes to perform every week - a 3 day temper leading up to match on Saturday would require a taper starting on Wednesday which is not ideal
41
Carb loading advantages
- CHO loading avoids the depletion of glycogen stores by increasing muscle and liver glycogen levels
- By sparing glycogen, it allows the aerobic athletes to maintain a higher intensity for a longer period of time
42
Carb loading disadvantages
- binding of H2O to CHO molecules increases water absorption, causing an increase in weight
43
Glycogen sparing
Is the ability of an athlete to spare glycogen supplied by using an alternative fuel source during physical activity
44
Glycogen sparing - 4 ways
Training effects
Caffeine consumption
Pre - event meal
During the event meal
45
Relative contribution of fuel (CHO and fats) at varying exercise intensities - crossover concept
The ‘crossover concept’ is a theoretical model that explains the balance of CHO and fat usage during sustained exercise
The crossover point is the intensity at which energy from CHO predominates over energy from fats, with further increases in intensity resulting in greater CHO use and decreases fat oxidisation
Low to moderate exercise intensity - trained individuals will delay the switch to CHO at they are better able to utilise fats as a fuel source, resulting in glycogen sparing
46
Hitting the wall 1- 4
The fuel source used for ATP production is based on the duration and intensity of exercise:
1. Low intensity/rest - stored fats are the main fuel source
2. As intensity of exercise increase, the contribution of muscles glycogen increases to meet the more immediate demands for fuel
3. There is enough glycogen stores in muscles to fuel up to 60 minutes depending on intensity (and also training and and CHO loading). Athletes “hit the wall” when muscle glycogen runs out
4. When muscle glycogen stores run out, the stored liver glycogen becomes the primary fuel source allowing exercise to continue but performance starts to diminish
47
Hitting the wall 5 -7
5. Depletion of liver glycogen affect the brain - decision making ability affected
6. Fats now become the primary fuel source and intensity of exercise is reduced as fats require more complex chemical reactions and greater amounts of oxygen
7. Depletion of fats results in protein being used as a fuel source
- this is only likely to occur in ultra endurance events
48
Immediate cardiovascular responses to physical activity 1-6 X4
Increased cardiac output
Increased heart rate
Increased stroke volume
Increased blood pressure
Blood redistribution
Increased arteriovenous oxygen difference
49
Increased cardiac output / short term (immediate) effects of physical activity (PA)
Immediate cardiovascular responses to physical activity
- Total amount of blood the heart pumps every minute
- Calculated by heart rate x stroke volume
50
Increased heart rate
Immediate cardiovascular responses to physical activity
- Number of times heart beats per minute
- To provide more rapid supply of fuel and energy to the muscles, heart rate increases during exercise
- This increase is directly proportional to the workload
51
Increased stroke volume
Immediate cardiovascular responses to physical activity
The amount of blood that is ejected from the left ventricle with each beat of the heart
52
Increased blood pressure
Immediate cardiovascular responses to physical activity
- Arterioles supplying working muscles vasodilate, so more blood is forced from arterioles into the capillaries surrounding the muscle
- BP sees a significant increase particularly in exercise which use large muscle groups such as running, cycling or swimming
53
Blood redistribution
Immediate cardiovascular responses to physical activity
- During exercise, arteries open up and contract to allow more or less blood to reach certain areas of the body
- Arteries taking blood to working muscles open up (vasodilate) to allow more blood to the muscles whilst arteries taking blood to non active areas of the body contract (vasoconstrict) to reduce blood flow. This increases the amount of blood available to the working muscles.
- To avoid overheating, the blood acts as a temperature regulator, taking heat from within the body to skin surface, where evaporation of sweat assists in cooling the body.
54
Increases arteriovenous oxygen difference (a-vO2 diff)
Immediate cardiovascular responses to physical activity
- A comparison of the oxygen in the arteries compared with the veins provides a measurement of muscle oxygen use.
- As more oxygen is extracted by the muscles during exercise, the avO2 difference increases - more oxygen is in the arterioles delivering the blood than is present in venules taking the blood away from the muscle.
- Increased cardiac output to the muscle and extraction of oxygen = greater oxygen availability at the muscle to be used during exercise
55
Increased respiratory rate
Immediate respiratory responses to physical activity
- the increased for oxygen and the removal of carbon dioxide during exercise results in an increased respiratory rate
- during exercise respiratory rate increases to meet the body’s demands to supply oxygen to working muscles
56
Increased tidal volume
Immediate respiratory responses to physical activity
- tidal volume refers to the amount of air inhaled and exhaled during normal respiration
- the increased need for O2 and the removal of CO2 during exercise results in an increased tidal volume
57
Increased ventilation
Immediate respiratory responses to physical activity
- increases in ventilation = tidal volume x respiratory rate
- ventilation is amount of oxygen consumed per minute
58
Increased gas exchange/ pulmonary diffusion
Immediate respiratory responses to physical activity
- diffusion - movement of a gas from high concentration to low concentration
- the air we breathe in is high in O2 content and low in CO2
- the air we breathe out is low in O2 content and high in CO2
—- as a result O2 diffuses from the alveoli into the surrounding capillaries whilst CO2 diffuses from the surrounding surrounding capillaries into the alveoli
- during exercise, ^ need for oxygen and removal of CO2 see;s ^ diffusion takes pace. An athletes uses more oxygen the available oxygen when at work compared to at rest
59
Increased oxygen uptake
Immediate respiratory responses to physical activity
- oxygen uptake increases dramatically during first few minutes of exercise (oxygen deficit) as the anaerobic energy system is the dominant energy provider
- once steady state is reached oxygen demand is met by oxygen supply
—- at this point an increase in exercise intensity is met by an increase in oxygen consumption
—- when an increase in exercise intensity no longer leads an increase in oxygen consumption
- as a result, athletes are forced to rely on their anaerobic (without O2) energy system to supply energy to the working muscles
- at the completion of exercise, oxygen consumption remains high (oxygen deficit) to assist with the recovery process
60
VO2 MAX
Refers to the maximum capacity of an individual’s body to transport and utilise oxygen during exercise, reflecting the aerobic capacity of the individual and is measure in L/min
61
Long term adaptations to training
Long term adaptations to training are those that occur as a physiological response to the increased demands placed on the body through trained
Training effects are specific to the type of training undertaken (aerobic or anaerobic) & to the system where the physiological change is occurring
Aerobic training
- cardiovascular
- respiratory
- muscular
Anaerobic training
- muscular
62
Cardiovascular adaptations
Aerobic training - cardiovascular adaptations
- ^ myocardial contractility
- ^ of left ventricle
- ^ SV
- Decrease HR submaximal exercise & rest
- ^ Q during maximal exercise
- ^ blood volume (^ plasma volume & ^ RBC count)
- Decrease blood pressure
- ^ volume of haemoglobin
- ^ capillarisation around heart & skeletal muscle
Cardiovascular adaptations are those which occur to the structure & function of heart, blood vessels (arteries, veins & capillaries & the blood)
63
Increased myocardial contraction ability
Aerobic training - cardiovascular adaptations
The heart
- the heart is a muscle (myocardium) & responds to training by getting bigger & stonger
- the increased in size of the heart enables the left ventricle to stretch more & thus fill with more blood
This increases the contract ability, resulting in ^SV & ^ blood supply to the body
64
Increased size of the left ventricle
Aerobic training - cardiovascular adaptations
The heart
- aerobic training results in hypertrophic of the heart muscle, characterised by:
Increase in the size of the left ventricular cavity
Thickening of the left ventricle walls
65
Increased stroke volume (SV)
Aerobic training - cardiovascular adaptations
The heart
SV ^ (at rest & during sub-maximal exercise) due to:
1. Increased contract ability of the myocardium - your heart can beat harder and can therefore eject more blood with each beat
2. An increased cavity size of left ventricle allows more filling of blood and therefore a greater volume to be ejected
3. Reduced heart rate allows longer rest period between beats and more opportunity for blood to enter left ventricle
66
Decrease heart rate (HR) during submaximal exercise and rest
Aerobic training - cardiovascular adaptations
The heart
The heart doesn’t have to work as hard to produce the required O2 and nutrients to the working muscles
Decrease steady state HR
Increase efficiency of the cardiovascular system means hat at submaximal intensities, trained athletes will reach a steady state at a lower HR
At submaximal exercise, cardiac output will remain unchanged, however, HR & SV will change following an aerobic training program
67
Increase cardiac output (Q) during submaximal exercise
Aerobic training - cardiovascular adaptations
The heart
Increase in maximum cardiac output due to increase in SV
Cardiac output increases at maximal workloads, which increases the delivery of oxygen & the removal of by-products & allows greater aerobic glycolysis to occur
E.g.
Rest
- Untrained : 5000ml = 7bpm x 71 ml
- Trained : 5000ml = 50 bpm x 100 ml
Maximal exercise
- Untrained : 20,000 ml = 200 bpm x 100 ml
- Trained : 30,000ml = 200 bmp x 150 ml
68
Increased blood volume (^ plasma volume & ^ in red blood cell count)
Aerobic training - cardiovascular adaptations
Blood
- highly trained endurance athletes have a blood volume 20-25% greater than an untrained subject
- plasma volumes increases:
Assist in increasing SV (more blood can fill during diastole)
Assist in regulation of bod temperature
- trained individuals are able to dissipate heat more quickly & economically than untrained individuals
This improves performance, as the heat generated by energy metabolism is less detrimental to performance
69
Increased volume of haemoglobin
Aerobic training - cardiovascular adaptations
Blood
- the total amount of haemoglobin in the blood increases with aerobic training
- haemoglobin is important for the transport of O2 from the lungs to the working muscles
- increases in blood volume are associated with greater amounts of haemoglobin, but the haemoglobin concentration does not increase
70
Increased capillarisation around heart & skeletal muscle
Aerobic training - cardiovascular adaptations
Blood vessels
- the increased capillarisation allows for improved blood flow to the heart delivering more O2 to the myocardium
- with aerobic training myocardium O2 consumption decreases due to a decreases HR & increase in SV
71
Decreased blood pressure
Aerobic training - cardiovascular adaptations
Blood vessels
- trained individuals have a lower BP, particularly systolic BP, due to capillarisation of the heart & muscles and enhanced elasticity of the arteries
72
Respiratory adaptations
Aerobic training - respiratory adaptations
- ^ total lung volume & vital capacity
- ^ tidal volume
- ^ diffusion
- ^ membrane source area
- Ventilation
- ^ ventilation efficiency
- ^ maximum oxygen consumption
- ^ maximal oxygen consumption (VO2 max)(VO2 remains the same or slightly lower at rest & during submaximal exercise)
- ^ oxygen delivery of the working muscles
- ^ ability of the muscles to extract the oxygen from the blood (the a-vO2 diff)
73
Long term respiratory adaptations as a result of aerobic training
Aerobic training - respiratory adaptations
Long term respiratory adaptations as a result of aerobic training allow for greater amounts of oxygen to be taken in & used by the body
The mechanisms responsible for this increase are either:
- structural - a result of changes to the respiratory system
- functional - a result of improved function of the respiratory system
74
Increased total lung volume & vital capacity
Aerobic training - respiratory adaptations
Structural adaptations
- an ^ lung capacity allows more oxygen to be inspired & transported to the working muscles
- total lung volume - amount of air in the lungs at the end of a maximal inspiration
- vital capacity - volume volume of air tat can be for fully expired after maximal inspiration
Aerobic training will result in an increases lung capacity, increasing the amount of oxygen that can be transported to the working muscles
75
Increased tidal volume
Aerobic training - respiratory adaptations
Structural adaptations
An increase in the volume of air inspired & expired with each breath results in the respiratory system reducing the number of breaths per minute (RR)
- this occurs as a result of more efficient cardio respiratory & muscular systems
76
Total lung volume
Volume of air inhaled during each breathe
77
Increased diffusion (movement of O2 into the lungs and CO2 out)
Aerobic training - respiratory adaptations
Structural adaptations
- ^ in diffusion is at rest & during submaximal & maximal exercise intensities
- diffusion increased due to the ^ in lung volume (which provides greater alveolar-capillary surface area & therefore more sites where diffusion can occur)
78
Increased membrane surface area
Aerobic training - respiratory adaptations
Structural adaptations
- diffusion of O2 across the alveolar-capillary membrane & of CO2 across the tissue-capillary membrane is greater in trained subjects
- increased capillarisation allows for more O2 to be transported to the working muscles & greater surface area for diffusion to take place
79
Ventilation
Aerobic training - respiratory adaptations
Functional adaptations
- more efficient gas exchange results in reduced ventilation at rest and submaximal exercise
- during maximal exercise, the ventilation of a trained athlete increases compared to untrained individuals
This results in an increased ability to transport greater amounts of oxygen to the working muscles
Ventilation increases proportional with CO2 production
80
VO2 max - maximal amount of oxygen your body can take in and use during exercise
Aerobic training - respiratory adaptations
Functional adaptations
With aerobic training:
VO2 remains the same or slightly lower at rest & during submaximal exercise
Maximal oxygen consumption during exercise (VO2 max) increases
- the change in VO2 max is a result of a number of changes:
- ^ oxygen delivery to the working muscles
- ^ ability of the muscles to extract the oxygen from the blood (a-vO2 diff)
81
Muscular adaptations
Aerobic training - muscular adaptations
These changes occur in the low-twitch fibres & include
- ^ fibre size (to a small degree due to ^ capillarisation)
- ^ capillarisation
- ^ number & size of mitochondria
- ^ myoglobin stores
- ^ glycogen stores
- ^ stores of oxidative enzymes
- ^ oxidation of fats at sub-maximal exercise (glycogen sparing)
- ^ muscle fibre adaptation
- decrease myocardial oxygen cost
Aerobic raining enhances the body’s ability to attract oxygen into the muscle cells & then use it to produce (ATP) for muscle contraction
- these adaptations are best produced through continued fartlek, & long interval training
82
Increased fibre size (to small degree due to increased capillarisation)
Aerobic training - muscular adaptations
Slow twitch fibres will increase in size (hypertrophy) as a result of aerobic training
- the increased in the size of slow-twitch fibres is closely associateassociated with with the increased capillary density surrounding the fibres
83
Increase capillarisation
Aerobic training - muscular adaptations
Aerobic training increases the number capillaries around cell at the site of the muscle
- allows for more oxygen to be transported to the working muscles and a greater surface area for diffusion to take place
- number of capillaries increase around each fibre type with greatest increase around slow twitch fibres
Increase in the number of capillaries around the muscle leads to an increase in the supply of O2, & other nutrients & enhanced removal of waste products from the muscle
84
Increased size & number of mitochondria (inn slow twitch fibres)
Aerobic training - muscular adaptations
- the mitochondria are the sites of ATP resynthesis, & where glycogen & triglycerides stores are oxidated
- the greater the number & size of the mitochondria located within the muscle, the greater the oxidisation of fuels to produce ATP aerobically
85
Increase myoglobin stores (in slow twitch fibres)
Aerobic training - muscular adaptations
- aerobic training significantly increases the myoglobin content in slow twitch fibres & therefore its ability to to extract O2 & deliver it to the mitochondria for energy production
86
Aerobic training increases the ability of the skeletal muscles to oxidise glycogen, particularly during maximal exercise
The adaptations that cause this increase are:
- increased glycogen storage
- increased stores of oxidative enzymes
- increased oxidisation of fats at sub-maximal exercise (glycogen sparing)
87
Increased glycogen storage
Aerobic training - muscular adaptations
- muscular hypertrophy causes an increase in the muscular stores of glycogen
88
Increases stores of oxidative enzymes
Aerobic training - muscular adaptations
- aerobic training increases the ability of the skeleton muscles to oxidise glycogen
- these enzymes increases by up to to 150% with training
- this in turn increases the rate of ATP production and therefore increases the level of performance significantly
- muscular hypertrophy is also accompanied by increases quantity & activity of glycolytic enzymes
89
Increased oxidisation of fats at submaximal exercise (glycogen sparing)
Aerobic training - muscular adaptations
- muscular adaptations result in a an increase in the capacity of muscle fibres to oxidise fats
- the increases oxidisation of fats as a fuel source is due to:
- an increase in intramuscular triglycerides
- an increase in free fatty acids
- an increase in oxidative enzymes
- increased oxidation of fats at sub-maximal intensities is beneficial to endurance athletes as it allows them to conserve (‘spare’) their glycogen stores, thereby allowing the athlete to work for longer periods
90
Muscular adaptations
Anaerobic training - muscular adaptations
Muscular hypertrophy
- (^ ATP, PC & Glycogen stores)
Increased capacity of the ATP-CP system
- ^ ATP & PC stores
- ^ ATPase enzymes
Increased alacrity of the anaerobic glycolysis system
- ^ glycogen stores
- ^ glycolytic enzymes
- ^ tolerance to metabolic by-products
^ capacity of the ATP-CP system
^ utilisation of glycogen
^ rate of ATP release from glycogen
^ breakdown & resynthesis of ATP
^ ability to work at high intensities
91
Muscle hypertrophy
Anaerobic training - muscular adaptations
- skeletal muscles are very adaptive - if you stress a muscle, it will adapt by increasing in size (hypertrophy)
- resistance training stresses the muscles so that they hypertrophy & increase in strength (mainly type IIB fast twitch fibres)
- hypertrophy occurs as a result of:
- increased size & number of myofibrils per muscle fibre
- increased amounts of contractile proteins (myosin & actin myofilaments)
Muscle hypertrophy accounts for the increase in energy substance (ATP, PC & Glycogen) due to the greater cross-sectional area
Muscle hypertrophy is more pronounced in males than females
92
Increased capacity of the ATP-CP system
Anaerobic training - muscular adaptations
- muscular hypertrophy is accompanied by increased muscular stores of ATP & creating phosphate (CP), as well as increasing the quantity & activity of enzymes which breakdown & resynthesis ATP
- by having more fuel available & the increase in enzyme quantity & activity which remakes ATP quicker, there is a faster restoration of ATP
- this benefits the athlete in activities that enquire speed, strength & power
Anaerobic training improves the body’s ability to store and restore ATP-PC, improving peat efforts during maximal exercise
93
ATPase
Is an enzyme which breaks down ATP into ADP (other enzymes assist in resynthesis)
94
Increased capacity of the anaerobic glycolysis system
Anaerobic training - muscular adaptations
- glycolytic capacity (the rate at which glycogen can be broken down into lactic acid) is also increased with anaerobic training, due to:
— increases in glycolytic enzymes
— increases in glycogen stores
- muscular hypertrophy is accompanied by increases muscular stores of glycogen, as well as increasing the quantity & activity of glycolytic enzymes which breakdown & resynthesis ATP
- the amount of ATP that can be delivered from the Anaerobic glycolysis system is therefore increased
- this leads directly to an increase in performance in activities that depend on the anaerobic glycolysis system for energy, such as a 400m race
95
Health-related fitness components
- cardiorespiratory endurance
- muscular strength
- muscular endurance
- flexibility
- body composition
96
Skill/performance- related fitness components
- power
- coordination
- balance
- agility
- speed
- reaction time
97
Cardio respiratory endurance
- the ability of the cardiovascular (heart, lungs & blood vessels) & respiratory system to produce aerobic energy/ATP
- together these systems deliver O2, & nutrients to muscles & remove by-products that have been produced by the body’s cells
- cardio respiratory endurance is dependent on the ability of the oxygen to take in O2, transport it & use it
98
Muscular strength
- the maximal force that can be generated by a muscle or muscle group in one maximal effort (1 RM)
- e.g. rugby scrum
99
Muscular endurance
- the ability of the muscle or muscle group to perform repeated contractions (concentric, eccentric or isokinetic) for an extended period of time, or to maintain a concentration for a extended period of time (isometric contractions) in the face of fatigue
- A muscle that has a high levels of endurance must ahead reduced levels of fatigue; therefore muscular endurance can be also be thought of as the opposite of fatigue
- The ability to sustain the contraction while fatigue increases is an important aspect of local muscular endurance
100
Flexibility
- Flexibility is the range of motion (ROM) around a joint
- Promotes healthy muscles and joints
- Prevents injury
- Improves elasticity of muscles and connective tissue around joints, which increases freedom production
- It is the capacity of a joint to move through its full range of motion, & reflects the ability of the muscle & connective tissue to stretch
101
Two types of flexibility
1. Static flexibility
- Refers to a joints range of motion under stationary conditions
2. Dynamic flexibility
- Refers to the resistance to motion in a joint. Someone with good dynamic flexibility will be able to move the joint throw its full range of motion quickly & easily
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Body composition
- the term used to describe the different components that, when taken together, make up a person’s body weight
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Muscular power
- The ability to exert a maximal contraction quickly or in one explosive effort (often mixed up with strength)
- Power = force x speed
- Force = speed
- Speed = speed at which movement occurs (distance/time)
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Coordination
- Refers to the skilful and effective interaction of movements.
- It is the ability to use the body’s senses to execute motor skills smoothly & accurately
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Balance
- Maintaining equilibrium while stationary or moving
- Static equilibrium - refers to activities where balance is maintained while the body is stationary
- Dynamic equilibrium - refers to maintaining balance while moving
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Agility
- The ability to change body position or direction and accurately while maintaining balance
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Speed
- The rate of motion (how fast you can move your body part from one point to another)
- Speed = distance x time
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Reaction time
- The time form the presentation of a stimulus to the onset of a response
109
Specificity
Training principles
- relevant to the energy system, position-specific movement and fitness requirements of an activity
- this information is gathered through a games analysis to understand the specific demands of the sport
- athletes get what they train for - swimming training does not improve cricket skills
- energy systems usage should be identified for the sport & for each individual position. This enables the appropriate training method to be selected
- aerobic - continuous, fartlek, or long interval training
- anaerobic - short interval, medium interval, HIIT, plyometrics training & careful considerations of duration & work to rest ratio
- fitness components that dominate the activity need to be identified, as do fitness components that dominate Foran individual in a team environment
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Progressive overload
Training principles
- overload - the planned, gradual increase in training load to ensure that fitness continues to be optimised
- applied once adaptation has occurred to a certain stimulus
- ensures that the training program produces chronic adaptations in the body performance improvements
- if overload is not applied, we see a plateau in performance
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Overload can be applied by:
Progressive overload
- increasing the number of repetitions
- increasing the number of sets
- increasing the distance
- increasing the intensity within the set zone
- increasing the duration of work
- decreasing the amount of rest
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Frequency
Training principles
- the number of times training occurs in a given period
- aerobic training for beginners requires 3 sessions per week to improve
- endurance athletes may Tran 5-6 x per week due to submaximal nature of training
- anaerobic training (strength, muscular power, plyometrics, etc.) takes pace 3-5 x per week. Sue to the increased intensity, greater recovery time is required between sessions
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Intensity
Training principles
- the magnitude of exertion required
- measured using following:
- heart-rate (%HR max)
- lactate concentration
- maximal speed
- rating of perceived exertion charts (RPE)
- aerobic adaptations require aerobic training zone (between 65-85% max HR or RPE 3-6)
- anaerobic adaptations requires an intensity greater than 85% max HR or RPE 8
114
Intensity
Training principles
- the magnitude of exertion required
- measured using following:
- heart-rate (%HR max)
- oxygen uptake (%VO2 max)
- lactate concentration
- maximal speed
- rating of perceived exertion charts (RPE)
- aerobic adaptations require aerobic training zone (between 65-85% max HR or RPE 3-6)
- anaerobic adaptations requires an intensity greater than 85% max HR or RPE 8
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Duration
Training principles
- the length of training time
- this can include time spend during:
- each session (minutes)
- total program (weeks or months)
- 20 minutes duration is required to make aerobic gains in a continuous activity
- gains in aerobic fitness take longer (12-16 weeks) than gains in anaerobic fitness/strength & power (8-10 weeks)
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Reversibility
Training principles
- the loss of physiology performance (detraining) occurs as a result of a erosion terminating or scaling back a regular training program
- this usually starts in the first 1 - 2 weeks and increases the longer the athlete remains out of training
- as a result, athletes employ various cross training activities during the ‘off season’ phase to avoid a severe detraining effect
- cross training also allows athletes to rest various muscle groups used during the season whilst retaining their aerobic base
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Training methods
Types
- resistance training - isometric, isotonic, isokinetic
- interval training
- continuous training
- circuit training
- fartlek
- flexibility
- plyometrics
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Resistance training
Training methods
Resistance training aims to build muscle strength, muscle power or local muscular endurance by exercising muscle groups against a resistance
- muscle fibres are recruited according to intensity levels
- slow-twitch fibres are recruited at lower intensities
- as intensity increases, fast-twitch fibres are recruited
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Resistance training - benefits
Training methods
- increases strength - allows an increase in force portion which can be adapted for improvement in both power and speed
- promotes weight loss & balance - improves body composition
- helps prevent osteoporosis
- improves dynamic stability & preserves functional capacity
- forms the foundation for the development of speed, power & agility
120
Resistance training - isotonic weight training, isometric resistance training, isokinetic training
Training methods
Isotonic weight training
- muscle changes length working against a constant load e.g. bicep curl, bench press, etc.
Isometric resistance training
- type of strength training where the joint angle and muscle length do not change during contraction
- this can be completed using the body’s own structure - e.g. holding a benchpress in a fixed position
Isokinetic resistance training
- an isokinetic force results in a change in muscle length against a varying load so that the resistance changes throughout the muscle’s range of movement
- cannot be done using free weights but requires expensive specialised equipment to ensure the speed of muscular contraction remains constant
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Interval training
Training methods
- series of repeated bouts of exercise interrupted by pre - determined rest periods or lighter exercise
- depending on the length of the work & rest period, interval training can be used to develop any of the three energy systems
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Interval training - benefits
Training methods
- high intensities can be maintained for the work phase of the program, enhancing the quality of the season
- pacing can be developed
- specific energy systems can be targeted
- lactate tolerance (medium-interval), high is crucial in many sporting pursuits, can be developed
- interval sessions can be specific to the game, with similar work-to-rest ratios
- sessions are highly structured
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Long interval training
Training methods
Long interval training is where the work period is dominated by the aerobic energy system
- this occurs when the work period is 1 minute or longer, or the work-to-rest ratio is 1:1 or greater (2:1, 3:1 etc)
- the aim of longer-interval training is to increase the performers lactate threshold (LT)
- beneficial in developing pacing (pace required to achieve a certain time in an aerobic dominated event)
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Intermediate interval training
Training methods
Immediate interval (or medium interval) training is where the work period is dominated by the anaerobic glycolysis system
- this occurs either when the work period is between 10 & 60 second or when the work-to-rest is 1:2 or 1:3
- the aim is to develop tolerance of lactic acid
- this is particularly important for team sports that regularly require performers to maintain high intensity output in the presence of metabolic by-products
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Short interval training
Training methods
Short interval training is where the work period is dominated by the ATP-CP energy system
- the rest comonentcannot be reduced below 1:6 as this would change the emphasis of the energy system being trained
- the aim of short-interval training is to improve speed and increase the amount of PC stores to enable the performer to work at their highest intensity for longer
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High intensity interval training
Training methods
High intensity interval training (HIIT) is a relatively new aerobic training concept involving periods of short, high intensity work followed by periods of lower intensity recovery
- shorter in duration than many of the more traditional aerobic training methods
- offers an effective training alternative to people with limited time
- a thorough warm-up is crucial before commencing the main phase of the session
- no set formula to HIIT training
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Continuous training (one slow distance training or low intensity steady state)
Continuous training involves performing an activity, such as jogging, cycling or swimming, nonstop for a period of time
- used to improve aerobic fitness and local muscular endurance
- to maximise the benefits of continuous training, a heart rate range of 70 - 85% max HR should be maintained of 20 minutes
- this is known as the aerobic training zone
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Continuous training - lactate threshold training
Lactate threshold training can be continuous in nature and requires an exercise intensity at or slightly above lactate threshold
- research suggests training at or close to one’s lactate threshold increases the intensity at which it occurs
- whilst it is difficult to measure ones exact lactate threshold outside of a laboratory, this is usually occurs by exercising at a heart rate of approximately 85-90% max HR
129
Circuit training
Circuit training comprises a sequenced performance of exercises at different activity stations (typically, between 8-12 stations) completed in a given time or by a pre-determined work:rest ratio
- the completion of each exercise in the circuit one is is known as lap (2 or 3 laps of exercise are usually performed in a circuit)
- can be tailored to suit the needs of an individual/ develop scientific components of fitness/ improve there overload fitness
- beneficial to improve multiple fitness components (speed, muscular endurance, balance & agility)
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Benefits of circuit training
- offers variety
- several fitness components can be targeted
- specific can be maintained
- can accomodate large groups of people
- minimal equipment is required
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Fartlek training
- fartlek training a variation of continuous training, involves changes of intensity throughout the training sessions
- these changes of intensity can be simply an increase in pace or running up a hill, & involve the addition of the anaerobic glycolysis energy system to help produce the increased amount of ATP needed for the increased intensity. As a result, it stimulates the interplay between the aerobic & anaerobic energy systems used in individual sports & in team games
- fartlek is mainly used y runners, the concept is equally useful for swimming, cycling, rowing & skiing basically any sport where a combination of aerobic & anaerobic energy is important
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Advantages of fartlek training
- improves both the aerobic and anaerobic energy systems & related fitness components (aerobic capacity, anaerobic capacity & speed)
- because of the random nature of fartlek, it s extremely difficult to overload, & considerable discipline is required to repeatedly perform random bursts of speed
133
Flexibility training
Improved flexibility will:
- improve sporting performance through enhancing developments in speed, strength and power
- reduce the likelihood of injury, particularly for performers who require a full range of motion in their sporting pursuits
- Improve posture
- reduce the impact of DOMS
- release stress & tension
134
Four major methods of flexibility training
Static stretching (performed without movement)
- muscle is held at is maximum range for a period of up to 30sec
- used to develop static flexibility
Dynamic stretching (performed with movement)
- muscle is moved through its range of motion (ROM) its controlled momentum, deigned to emulate the expected movements you are about to perform
- e.g. before a game of AFL - player swinging their leg, simulation the move to of kicking
- most suited to warm up as it moved the muscle through the full ROM
Ballistic stretching (performed wth explosive movements)
- involves using the momentum of moving body or a limb in an attempt to force it beyond its normal range of motion
- involves bouncing into or out of a stretched position
- potentially dangerous, so only appropriate in limited circumstances (e.g. ballet dancer)
- Proprioceptive Neuromuscular facilitation (PNF) stretching
Advanced for flexibility training involving the contraction and stretching of specific muscle groups
Should only be performed under the guidance of individuals as there a risk of overstretching causing injury
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Plyometrics training
Plyometrics is a training method designed to produce fast, powerful movements, and to improve the functions of the nervous system
- the aim of plyometrics is to increase muscular power by first stretching a muscle & then contraction it in the shortest possible time
- involves rapid movements aimed at using the strength and elasticity of a muscle to jump higher, run faster, throw farther, or hit harder, depending on the demands of the sport you are training for
- because of the explosive nature, care needs to be taken to minimise the risk of injury when introducing a plyometrics program
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Consider the following guidelines:
Plyometrics training
- a strength base is recommended before commencement of a plyometrics program
- appropriate footwear, warm-up and surface are paramount
- lower-intensity plyometrics exercises should be usually initially, before progressing to harder exercises
- ample rest (at least one minute) is required between sets
- when performance concurrently with another training methods (such as short interval or stretch training), 2 sessions per week are sufficiency to elicit improvements/prevent injury
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Immediate respiratory responses to physical activity
Increased respiratory rate
Increased ventilation
Increased gas exchange/pulmonary diffusion
Increased tidal volume
Increased oxygen uptake
Atar Physed Units 1 & 2
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