edexcel a level physical education a 9536 next previous unit 6 a.3.1 edexcel examinations a level...
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Unit 6 A.3.1
Edexcel A Level Physical Education A 9536
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Edexcel ExaminationsA Level Physical Education
A 9536
Unit 6 : Section Apart 3
Scientific Principles of Exercise and Performance
Unit 6 A.3.2
Edexcel A Level Physical Education A 9536
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INDEX20 - SHORT-TERM RESPONSE TO AEROBIC ACTIVITY
THE AEROBIC SYSTEM / AT REST21 - SHORT-TERM RESPONSE TO AEROBIC ACTIVITY THE AEROBIC SYSTEM22 - SHORT-TERM EFFECTS OF AEROBIC EXERCISE - a-vO2
diff23 - SHORT-TERM METABOLIC RESPONSE TO AEROBIC
ACTIVITY24 - LONG-TERM VASCULAR ADAPTATIONS TO AEROBIC
TRAINING25 - LONG-TERM METABOLIC ADAPTATIONS TO AEROBIC
TRAINING26 - LONG-TERM NEUROMUSCULAR ADAPTATIONS TO
AEROBIC TRAINING27 - FOOD FUEL UTILISATION DURING AEROBIC EXERCISE
GLYCOGEN SPARING28 - ONSET OF BLOOD LACTATE ACCUMULATION (OBLA) LONG-TERM ADAPTATIONS OF OBLA TO AEROBIC
TRAINING29 - CELLULAR ADAPTATION PRODUCED BY AEROBIC
TRAINING30 - GENERAL LONG-TERM ADAPTATIONS PRODUCED BY
TRAINING INDIVIDUAL RESPONSE / SWEATING / REGRESSION31 - GENERAL LONG-TERM CELLULAR ADAPTATIONS TO
TRAINING NEURAL / MUSCLE CELLS
Index
3 - ERGOGENIC AIDS4 - ERGOGENIC AIDS
CARBOLOADING5 - ERGOGENIC AIDS CREATINE / GLUTAMINE / CAFFEINE / ALCOHOL6 - ERGOGENIC AIDS - BLOOD DOPING / rEPO7 - ERGOGENIC AIDS ALTITUDE TRAINING - PSYCHOLOGICAL / THERAPIES8 - ERGOGENIC AIDS - MECHANICAL9 - ERGOGENIC AIDS AMPHETAMINES / BETA BLOCKERS / HGH ANABOLIC STEROIDS10 - RESPONSES TO TRAINING11 - THE ENERGY CONTINUUM
VARIATION IN CONTRIBUTION OF ENERGY SYSTEMS12 - HIGH INTENSITY EXERCISE
SHORT-TERM RESPONSES13 - THE LACTIC ACID SYSTEM
EFFECTS OF CONTINUED HIGH INTENSITY EXERCISE14 - THE LACTIC ACID SYSTEM
OBLA15 - FOOD FUEL USAGE DURING HIGH INTENSITY EXERCISE
DURING HIGH INTENSITY EXERCISE16 - LONG-TERM ADAPTATIONS TO HIGH INTENSITY
TRAINING ANAEROBIC17 - LONG-TERM NEUROMUSCULAR ADAPTATIONS
PRODUCED BY STRENGTH (ANAEROBIC) TRAINING MUSCLE CELL RESPONSE18 - LONG-TERM NEUROMUSCULAR ADAPTATIONS
PRODUCED BY STRENGTH(ANAEROBIC) TRAINING19 - LONG-TERM NEUROMUSCULAR ADAPTATIONS
PRODUCED BY STRENGTH (ANAEROBIC) TRAINING NEURAL / CONNECTIVE TISSUE RESPONSES
Unit 6 A.3.3
Edexcel A Level Physical Education A 9536
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ERGOGENIC AIDS
Fatigue and Recovery Process
ER GO GEN I C A I DStherapies
m echanical
psycho logical
nutrition
legal physio logical
illegal physio logical
illegal pharm aceutical
Unit 6 A.3.4
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ERGOGENIC AIDSFatigue and Recovery Process
NUTRITIONALDIETARY MANIPULATIONCARBOLOADING• aims to raise muscle glycogen stores above their normal resting levels• prior to endurance competitions with over 90 minutes continuous
activity• suitable for activities with low anaerobic and high aerobic components
• based on :• depletion - prolonged exercise to reduce levels of liver and muscle
glycogen stores - at least seven days before event• repletion - a high CHO diet in the period (three to four days) before
activity• combined with light exercise or rest
• also suitable for activities lasting 15 - 20 minutes• with a two day high CHO diet beforehand (see previous slides)
ERGOGENIC AID• any substance or method
which enhances performance
Unit 6 A.3.5
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ERGOGENIC AIDSFatigue and Recovery Process
NUTRITIONALDIETARY MANIPULATIONCREATINE SUPPLEMENTATION• creatine is a substance found in skeletal muscle• stored as phosphocreatine (PC)• supplementation increases PC levels to enhance the ATP-PC system of
ATP resynthesis• thereby delaying the alactic / lactic thresholdGLUTAMINE• is an amino acid forming part of skeletal muscle and immune cells• supplementation after exercise therefore reinforces the immune system
and reduces the risk of infectionCAFFEINE• stimulates the CNS but acts as a diuretic - this can lead to dehydration• illegal in large quantitiesALCOHOL• a relaxant in quite small quantities• absorbed into the body as an alternative to water therefore causes
dehydration• quite small quantities of alcohol can cause a drastic loss of performance
Unit 6 A.3.6
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ERGOGENIC AIDSFatigue and Recovery Process
ILLEGAL PHYSIOLOGICALBLOOD DOPING• involves the removal of athlete’s own blood which is then stored• the athlete’s body then remanufactures blood to replace that
taken• then the stored blood is reinfused• this temporarily increases red blood cell count (polycythemia)• problem of mis-matching can lead to a transfusion reaction
• increases VO2max and hence energy delivery to enhance aerobic performances
rEPO• involves infusion of hormone recombinant erythropoietin 6
weeks prior to major event• stimulating erythrocytes (up to 10% more) - red blood cells
• increases VO2max and hence energy delivery to enhance aerobic performances
• but elevates red blood cell production that can reach toxic life-threatening levels
• other risks are blood clots, strokes / coronary thrombosis, very low resting heart rates
Unit 6 A.3.7
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ERGOGENIC AIDSFatigue and Recovery Process
LEGAL PHYSIOLOGICALALTITUDE TRAINING• a predominantly endurance-based exercise programme used by elite endurance
athletes from a range of sports• consisting of 2 visits of at least two weeks duration per visit, to altitude (normally
between 1800-3000 metres)• second visit just prior to major competition• training at altitude uses the fact that the body will create more haemoglobin • to compensate for the reduction in oxygen available• benefits : reversible physiological adaptations
– increased Hb concentration– increases in myoglobin mitochondria and oxidative enzymes
• hence on return to sea level we have an increased VO2max and tissue cell respiration leading to enhanced aerobic performance
• risks : hypoxia, altitude sickness
PSYCHOLOGICAL• imagery / hypnosis stimulate mental rehearsal of relevant skills • by activating neural pathways that reinforce skill
THERAPIES• physiotherapy / acupuncture / herbal medicines used in injury treatment• reduce muscle soreness and aid recovery of local damaged tissue
Unit 6 A.3.8
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ERGOGENIC AIDSFatigue and Recovery Process
MECHANICALNASAL STRIPS• use of sticky plaster placed over bridge of nose to enlarge
nasal cavity• enables easier breathing
SPECIALIST EQUIPMENT• carbon fibre bike frames are lighter and
aerodynamically more efficient• specialist training machines
– concept II ergo rower– swimming ergo– flumes for rowing / swimming / canoeing– treadmill
SPECIALIST CLOTHING• cycling helmets and lycra sports clothing reduces air
resistance• Denise Lewis one shoulder javelin suit, bench press and
squatting suits– provide extra force in required directions
Unit 6 A.3.9
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ERGOGENIC AIDS
Fatigue and Recovery Process
ILLEGAL PHARMACEUTICALAMPHETAMINES• act as CNS stimulants to increase arousal levels
BETA BLOCKERS • reduce HR and BP thereby reducing tension, but can lead to
heart failure
HUMAN GROWTH HORMONE (HGH) • stimulates bone growth and increased lean body mass• give artificial increased strength / power outputs
ANABOLIC STEROIDS • increase lean body mass, but reduce natural secretions of
gonadotrophins • females acquire masculine features such as facial and body
hair and deep voices• give artificial increased strength / power outputs
Unit 6 A.3.10
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RESPONSES TO TRAININGShort / Long-term Responses
SHOR T-TER MR ESPONSES TO
TR AI N I NG
m etabolicresponse
2 secondsATP
7-9 secondsATP/ PC
45 secondslactic acid
indefiniteaerobic
LONG-TER MAD APTATI ONSTO TR AI N I NG
m etabolicresponse
HIGH INTENSITYSHORT DURATION
LOW INTENSITY LONG DURATION
Unit 6 A.3.11
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THE ENERGY CONTINUUMVARIATION IN CONTRIBUTION OF ENERGY SYSTEMS
• as time progresses during intense exercise, the following chart shows the contribution of the different energy systems to the resynthesis of ATP
Short / Long-term Responses
Unit 6 A.3.12
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HIGH INTENSITY EXERCISESHORT-TERM RESPONSESATP muscle stores are depleted
within 2 secondsATP/PC system• rising ADP levels stimulate
the breakdown of PC stores • in coupled reaction with ADP
pool• peak anaerobic power
attained within first 5 seconds of flat-out exercise
• depletion of PC occurs between 7-9 seconds
Short / Long-term Responses
• on the graph, the ATP level is maintained (after an initial small drop) then falls as PC is used up
• by the energy from PC being used to resynthesise ATP
• so PC levels fall rapidly
• capacity to maintain ATP production at this point depends on lactic acid system
Unit 6 A.3.13
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THE LACTIC ACID SYSTEM
EFFECTS OF CONTINUED HIGH INTENSITY EXERCISE• glycolysis or incomplete breakdown of glucose molecule• small energy yield of 2ATP per glucose molecule• dominant between 10-60 seconds
• increased lactic acid production to and beyond lactic threshold (OBLA) see next three slides
• reduced pH inhibits glycolytic enzymes GPP, PFK and LDH• increased muscle fatigue and pain• delayed onset of muscle soreness (DOMS) occurring
24-48 hours after exercise• particularly following plyometric (eccentric) training• produces a marked reduction in physical performance•
• capacity to maintain ATP production then begins to rely on the aerobic system
Short / Long-term Responses
Unit 6 A.3.14
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THE LACTIC ACID SYSTEM
OBLA• as work intensity increases lactic
acid starts to accumulate above resting values
• at a certain point this produces muscle fatigue and pain
• the resultant low pH inhibits enzyme action and cross-bridge formation
• hence muscle action is inhibited• physical performance deteriorates
Short / Long-term Responses
• OBLA depends on the level of training
• and lies between 2 and 4 mmol l-1
Unit 6 A.3.15
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FOOD FUEL USAGE DURING HIGH INTENSITY EXERCISE
DURING HIGH INTENSITY EXERCISE
Short / Long-term Responses
Unit 6 A.3.16
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LONG-TERM ADAPTATIONS TO HIGH INTENSITY TRAINING
Short / Long-term Responses
LONG-TERM ADAPTATIONS TO AN ANAEROBIC TRAINING PROGRAMME
• increases in stores of ATP and PC
• and amounts of anaerobic enzymes such as creatine kinase
• result in more energy to be available more rapidly
• and therefore increases in maximum possible peak power
• and a delay in the ATP/PC to lactic threshold
Unit 6 A.3.17
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LONG-TERM NEUROMUSCULAR ADAPTATIONS PRODUCED BY STRENGTH (ANAEROBIC) TRAINING
Short / Long-term Responses
MUSCLE CELL ADAPTATIONS (FAST TWITCH FIBRES)• muscle hypertrophy (of fast twitch fibres) increases cross sectional area
of existing fibres by increasing :– number of myofibrils within each muscle cell– sarcoplasmic volume– contractile proteins : actin and myosin– mass of fast twitch fibres– number of fast twitch fibres (hyperplasia)
• hence % of type II increases and % of type I decreases• increase in muscle cell stores such as ATP, PC, and glycogen• increase in anaerobic enzymes such as creatine kinase (CK), PFK, GPP, and
LDH• increase toleration of lactate in fast twitch fibres• improved ability to remove lactate from muscle cell into blood• therefore enhancement of alactic / lactate and lactate / aerobic thresholds -
delay in OBLA• hence improved capacities of alactic and lactic acid systems to
resynthesise ATP• and ability to maintain maximal power output for longer• decrease in DOMS, particularly following eccentric training
Unit 6 A.3.18
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Short / Long-term Responses
ATPCP
glycogenglycolytic enzymes
lactic acid
ATPCP
glycogenglycolytic enzymes
lactic acid
AFTER SEVERAL WEEKS OF STRENGTH (ANAEROBIC) TRAINING
= SLOW TWITCH MUSCLE FIBRE (type I) (starts small gets smaller)= FAST TWITCH MUSCLE FIBRE (type II) (starts big gets bigger)
MUSCLE CELLBEFORE TRAINING
LONG-TERM NEUROMUSCULAR ADAPTATIONS PRODUCED BY STRENGTH(ANAEROBIC) TRAINING
Unit 6 A.3.19
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LONG-TERM NEUROMUSCULAR ADAPTATIONS PRODUCED BY STRENGTH (ANAEROBIC) TRAINING
Short / Long-term Responses
NEURAL ADAPTIVE RESPONSE• increased rate of response of CNS (Central Nervous
System)• recruitment of additional fast twitch fibre motor units• improved coordination of fast twitch fibre motor
units• toughening of proprioceptors so that more force is
required to stimulate inhibitory signals
CONNECTIVE TISSUE ADAPTATIONS• increase in thickness and strength of tendons• increased flexibility of ligaments• thickening and improved elasticity of cartilage• strengthening of bone tissue due to increased
depositing of calcium• therefore reduced risk of injury
Unit 6 A.3.20
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SHORT-TERM RESPONSE TO AEROBIC ACTIVITY
THE AEROBIC SYSTEM• unlimited supply of energy• to sustain the forces needed during low
intensity and long duration activity
AT REST• ATP utilisation is slow• a mixture of fats and carbohydrates is
used to resynthesise ATP
• the graph shows that initially CHO is the major supplier of chemical energy
Short / Long-term Responses
• the longer the exercise the greater utilisation of fats
• as muscle and liver glycogen stores become depleted
Unit 6 A.3.21
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SHORT-TERM RESPONSE TO AEROBIC ACTIVITY
THE AEROBIC SYSTEM• requires CHO in the form of
glucose• which is derived from
glycogen stored in muscle cells (mostly ST slow twitch)
• or in the liver• the graph shows how the rate
of usage of muscle glycogen is high during the first 30 minutes of steady exercise
Short / Long-term Responses
• the amount of glycogen remaining
• depends on the intensity and duration of the exercise
• and the CHO content of diet prior to exercise
• once the glycogen is used it may take days to fully replenish
• again depending on diet
Unit 6 A.3.22
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SHORT-TERM EFFECTS OF AEROBIC EXERCISE
Short / Long-term Responses
a-vO2 diff
• note that the blood draining from working muscle tissue may be almost completely depleted of oxygen
• however, the mixed venous return would still have around 5ml/dl because it is a mixture of blood from the working muscles and less active parts of the body combined
a-vO2 diff - AT REST
venule capillary arteriole
blood flow15ml O2
per 100ml blood20ml O2
per 100ml blooda-vO2 diff = 5ml
per 100ml blood
a-vO2 diff - DURING INTENSE EXERCISE
venule capillary arteriole
blood flow5ml O2
per 100ml blood20ml O2
per 100ml blooda-vO2 diff = 15ml
per 100ml blood
Unit 6 A.3.23
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SHORT-TERM METABOLIC RESPONSE TO AEROBIC ACTIVITY
METABOLIC RESPONSE
Short / Long-term Responses
• oxygen consumption or VO2 reflects the metabolic activity of the body and increases linearly with work
• then it levels out as the pulmonary system reaches its maximum capacity for rate of absorption of oxygen
• examples :Activity VO2 ml/kg/min-1
At rest 3.5Walking 10Jogging 20
At VO2max 55
Unit 6 A.3.24
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LONG-TERM VASCULAR ADAPTATIONS TO AEROBIC TRAINING
Short / Long-term Responses
VASCULAR ADAPTATIONS
• arteriovenous oxygen difference (a-vO2diff)
• a-vO2diff increases with training particularly at maximal workloads
• due to increased oxygen extraction by active tissue• caused by :
– more effective blood shunting– improved capillarisation of trained muscle – more efficient use of existing capillaries
a-vO2 diff - AT REST
venule capillary arteriole
blood flow15ml O2
per 100ml blood20ml O2
per 100ml blooda-vO2 diff = 5ml
per 100ml blood
a-vO2 diff - DURING INTENSE EXERCISE
venule capillary arteriole
blood flow5ml O2
per 100ml blood20ml O2
per 100ml blooda-vO2 diff = 15ml
per 100ml blood
Unit 6 A.3.25
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LONG-TERM METABOLIC ADAPTATIONS TO AEROBIC TRAINING
Short / Long-term Responses
LONG-TERM METABOLIC ADAPTIVE RESPONSE
• example data of VO2max ml/kg-1min-1
• gender and training differences
Group Age Male Female
Non athletes 10-19 47-56 38-4620-29 43-52 33-42
Basketball 18-30 40-60 43-60 Cross-country skiing 20-28 65-94 60-
75 Gymnastics 18-22 52-58 36-50 Rowing 20-35 60-72 58-65 Runners 18-39 60-85 50-75
• note that in the above data untrained females have much lower VO2max values (between 20-25%) compared with untrained males
• whereas endurance-trained females have VO2max values much closer to those of endurance-trained males (about 10% lower)
Unit 6 A.3.26
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LONG-TERM NEUROMUSCULAR ADAPTATIONS TO AEROBIC TRAINING
Short / Long-term Responses
ADAPTATIONS PRODUCED BY AEROBIC TRAINING
MUSCLE CELL ADAPTATIONS• more myoglobin is created in muscle cells• more and bigger mitochondria in muscle cells• increased oxidative enzymes glycogen phosphorylase,
phosphofructokinase, lipoprotein lipase• hence increased activity of Kreb’s cycle and electron transport chain• and increase in stores and utilisation of fat• increase in stores of glycogen in muscle• which enables more fuel to be available for aerobic work
• conversion of type IIb to type IIa fibres
NEURAL ADAPTATIONS• better recruitment of slow twitch fibre motor units making muscle
usage more efficient
Unit 6 A.3.27
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FOOD FUEL UTILISATION DURING AEROBIC EXERCISEShort / Long-term Responses
GLYCOGEN SPARING AS A LONG-TERM ADAPTATION TO AEROBIC TRAINING
• for the person who has undertaken sustained aerobic training
• an adaptation is produced where fats are used earlier on in exercise
• thus conserving glycogen stores (respiratory exchange ratio (RER) indicates greater use of fats)
• the graph shows a higher proportion of fats utilised by the trained person
• thereby releasing CHO for higher intensity work
Unit 6 A.3.28
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ONSET OF BLOOD LACTATE ACCUMULATION (OBLA)
LONG-TERM ADAPTATIONS OF OBLA TO AEROBIC TRAINING
• this point governs the lactic aerobic threshold
• trained athletes begin OBLA at higher work intensities
• and higher values of VO2max than untrained people
Short / Long-term Responses
Unit 6 A.3.29
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CELLULAR ADAPTATION PRODUCED BY AEROBIC TRAINING
Short / Long-term Responses
glycogenfats
oxygen uptake
glycogenfats
oxygen uptake
AFTER SEVERAL WEEKS OF AEROBIC TRAINING
= SLOW TWITCH MUSCLE FIBRE (type I)= FAST TWITCH MUSCLE FIBRE (type II) (do not increase in size)
BEFORE TRAINING
Unit 6 A.3.30
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GENERAL LONG-TERM ADAPTATIONS PRODUCED BY TRAINING
Short / Long-term Responses
INDIVIDUAL RESPONSE• adaptive response depends on individual
– fitness– cultural differences– gender– psychological factors– maturation
SWEATING• improved ability to sweat• more efficient heat loss
REGRESSION• when training stops, adaptive responses cease• the longer the training the more stable the adaptation
Unit 6 A.3.31
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GENERAL LONG-TERM CELLULAR ADAPTATIONS TO TRAINING
NEURAL CELLS• increased rate of firing of CNS, therefore increased
stimulation of motor units• therefore increased recruitment of FT and ST motor
units
MUSCLE CELLS• increased rate of cellular respiration means
increased O2 consumption
• or increased use of energy stores causes a decrease in PC and glycogen in ST and FT fibres
• decrease in triglycerides, oxymyoglobin stores
• increase in ADPs , Mg++, Ca++
• reduced pH inhibits cellular enzymes
• resulting in a general increase in muscle fatigue as muscular performance reduces
Short / Long-term Responses