Exercise physiology

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ATP/PC system

  • anaerobic 
  • high intensity activities lasting less than 10seconds (5-8)
  • takes place in the sarcoplasm 
  • stored ATP broken down to from ADP and P
  • release energy used for muscle contractions 
  • Phosphorcreatine is broken down by creatine kinase to P, C and energy. 
  • energy used to resynthesise ATP form ADM and P
  • couple reaction
  • alactic anaerobic 
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Advantages and Disadvantages of ATP/PC system

Advantages 

  • no fatiguing by products 
  • oxygen not required
  • energy released quickly for high intensity exercise 

Disadvanatges 

  • limited duration due to limited supply for PC - max 10 seconds
  • leads to big oxyegn debt
  • full recovery takes 3 minutes
  • PC needs oxyegn to be resynthesised 
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The lactate system

  • takes place in sarcoplasm 
  • activities lasting from 10 seconds to 3 minutes (peaks at 1 minute)
  • glycolysis 
  • glycogen --> uses enzyme PFK to generate gluocse --> pyruvic acid --> lactic acid
  • 2 net ATP molecules
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Advantages and disadvantages of lactic acid system

advantages 

  • ATP resynthesised quickly because there a few chemical reactions
  • no oxygen required
  • can be used for a sprint finish (i.e. to produce an extra burst of energy)
  • lactic acid can be reconverted and energy used later duirn aerobic exercise 

disadvantages

  • produces lactic acid as a fatiguing by product
  • only a small percentage of energy in glycogen is released 
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The aerobic system

  • glycolysis - Krebs cycle - electron transport chain 

Krebs cycle

  • pyruvic acid combines with acetyl coA
  • fatty acids undergo beta oxidation and combine with acetyl CoA
  • oxaloacetic acid already in the Krebs cyle combines with coenyzme A to form citirc acid
  • oxidation of citric acid
  • carbon dioxide removed 
  • hydrogen ions passed onto the electron trasnport chain
  • resynthesis of 2 ATP molecules

ECT

  • hydrogen ions split into ions and electrons
  • ions are oxidised to form water
  • hydrogen electrons provide energy to resynthesise ATP 
  • 34 molecules are formed 
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Advantages and disadvantages of aerobic system?

advantages

  • efficient - more ATP can be produced
  • no fatiguing by products 
  • large stores of glycogen and triglyceride so exercise can last a long time

disadvantages

  • multiple reactions - slower
  • takes a wahile for enough oxygen to become avaliable 
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Sources of energy

carbohydrates 

-in the form of glucose and glycogen 

Fats

-trigylcerides, and fatty acids

Protein 

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The energy contiuum

Refers to the continual movement from one energy system to another depending on the intensity and duration of the exercise

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Lactate threshold

the level of exercise intensity at which you are producing more lactate than can be removed. lactic acid starts to accumulate in the bloodstream and muscle (owing to excess hydrogen combining with pyruvate to form lactate)

  • performance starts to deteroriate and the intensity of the workload starts to decrease
  • too may lactic leads to fatigue because of high acidity inhibiting enzymes 

lactate threshold -----> keep working at high intensity -------> OBLA

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OBLA

4mmol of blood lactate for eac litre of blood

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V02 max and factors affecting it

The maximum volume of ozygen that can be take in and used by the muscle per minute

  • gender
  • age
  • lifestyles
  • training
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Why does VO2 max help sustain performance?

  • the more oxyegn that can be brought and used within the mitochondria, the longer the performer can work without accumulating lactic acid
  • lactic acid accumulates where there is no oxygen and the lactic acid system has to supply energy
  • more oxygen avaliable means lactic acid broken down quickly
  • OBLA delayed
  • increase oxygen carrying capacity 
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Factors that affects the rate of lactate accumulat

  • OBLA - point at which lactate starts to accumulate in the muscle - starts at 4mmol/litre
  • occurs as body is unable to provide enough oxygen to break down lactic acid
  • intensity of exercise - higher intensity the faster OBLA occurs
  • fitness of the performer - fitter the athlete the higher the delay in OBLA due to physiological adapative responses due to training 
  • V02 max - the higher the level the more delayed OBLA
  • respiratory exchage ratio - closer the value to 1.00 quicker OBLA occurs
  • muscle fibre type - if slow twitch fibres used, delays OBLA
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Causes of fatigue

  • glycogen depletion 
  • lactic acid build up
  • reduced rate of ATP synthesis 
  • reduced levels of calcium
  • reduced levels of acetylcholine 
  • thermoregulation
  • lack of PC
  • dehydration/electroyle depletion
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EPOC

Excess post oxygen consumption 

-oxygen deficit

-oxygen consumptin during exercise 

-EPOC (fast and slow component)

-oxygen consumption at rest

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The fast EPOC stage

  • the alactaid component 
  • no lactic acid is formed
  • ATP and PC levels are restored
  • myoglobin reloaded with oxygen 
  • 50% of PC restored after 30 seconds
  • 100% of PC resotred after 3 minutes
  • elevated rates of respiration 
  • uses 2-4 litres of oxygen
  • takes 2-3 minutes 
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The slow EPOC stage

  • the lactic acid component
  • concerned with the removal of lactic acid
  • oxidation into pyruvate then carbon dioxide and water in inactive muscle and organs
  • conversion into glycogen (cori cycle) and then stored in the muscle liver
  • converted into protein
  • converted into glucose
  • excreted in sweat and urine 
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MUSCLES

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Control of muscle contraction

proprioceptors 

  • sense organs in the muscles, tendons andjoints that inform the ody of the extent of movement that has taken place

muscle spindle apparatus 

  • made up of very sensitive proprioceptors that lie between skeletal muscle fibres. provide information about muscle length. if the muscle stretches the spindle also stretches and this sends an impulse to the spinal cord. if the muscle is stretched too fair, the muscle spindle appratus alters tension within the muscle, causing a strethc reflex which automatically shortens the muscle

golgi tendon organs 

  • provide information to the CNS about the degree of tension or stretch in the msucle. twhen stretched, they trigger the reflex inhibition of the muscle that is contracting and stretching the tendon, and the reflex contraction of the antagonist muscle
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Sarcomere

  • reoccuring units that make up a myofibril 
  • M H A I Z 
  • H zone - made of myosin - thick filaments
  • I band - made of actin - thin filaments
  • A bands - overlapping actin and myosin filaments 
  • Z lines 
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changes to the sarcomere

-myofilaments themselves don't contract - myosin and actin filaments slide other to make the sarcomere contract

  • z lines get closer together
  • sarcomeres get shorter
  • width of the I band decreases - gets shorter
  • width of the H zone decreases - gets shorter
  • A band stays the same 
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sliding filament theory

  • nerve impulses arrive at the neuromuscular junction 
  • at rest the sarcoplasmic reticulum stores large amount of calcium ions
  • electrical nerve impulse travels into the myofibril via the transevere tubules and triggers the release of calcium ions from the sarcoplasmic reticulum 
  • at rest tropomyosin strands prevent myosin from attaching to and pulling actin
  • calcium ions bind to troponin causing it to change shape
  • neutralises tropomyosin and frees up the actin binding site for myosin
  • myosin heads now binds to actin and forms a cross bridge
  • ADP and P are released from myosin which causes mysoin to move - power stroke
  • another ATp used to detach mysoin from actin so another cross birdge can form further up
  • mysoin reattaches, ratchet-like mechanism
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role of ATP in muscle contraction

  • prepares myosin for binding by moving it to a higher energy state and a cocked position 
  • once the myosin forms a cross bridge with actin, the ADP dissacciates and the myosin undergoes a power stroke, reaching a lower energy state when the sarcoemere shortens
  • ATP must bind to myosin to break the cross birdge and enable to mysoin to rebind 
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the role of troponin and tropomyosin

  • tropomyosin prevents myosin attaching to actin filaments
  • action potential causes calcium ions to be released from sarcoplasmic reticulum 
  • calcium ions attach to troponin on actin filaments
  • cause shape of troponin to alter
  • troponin neutralises the tropomyosin and exposes myosin binding site on actin filament
  • allows myosin to bind to actin, cross-bridge formed
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Types of muscle fibre

  • type 1 - slow twitch - slow oxidative 
  • type IIa - FOG - fast oxidative glycolytic 
  • type IIb - FGT - fast glycolytic fibres
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Characteristics of muscle fibres

  • fibres per motor neurone
  • motor neurone size
  • mitochondrial density 
  • glycogen store
  • triglyceride store
  • aerobic capacity 
  • anaerobic capacity 
  • capillary density 
  • contractile speed
  • force produced
  • fuel 
  • fatigability 
  • fatigue resistance 
  • motor neurone strength
  • oxidative activity 
  • glycolytic activity 
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Motor unit

  • compromises of one motor neurone and its corresponding muscle fibres
  • each muscle fibre does contract or does not - all or nothing law
  • threshold - minimum amount of stimulation 
  • all fibres within a motor neurone are the same type
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Motor unit

  • compromises of one motor neurone and its corresponding muscle fibres
  • each muscle fibre does contract or does not - all or nothing law
  • threshold - minimum amount of stimulation 
  • all fibres within a motor neurone are the same type
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Varying strength of muscle contraction

  • size of motor units
  • amount of motor units - multiple unit summation
  • type of muscle fibre
  • wave summation - increase frequency of impulse - motor unit unable to relax - increases of contraction
  • tetanic contraction - if wave summation continues a tetanic contraction will occur - more powerful - muscle spindles detect change in muscle length, send information to brain, compares information to LTM to ensure correct force applied based on past experiences
  • spatial summation  - rotating the frequency of the impulse in motor units to delay fatigue.
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MECHANICS OF MOVEMENT

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Linear motion

  • mass - amount of matter in our body 
  • weight - the force on a given mass due to gravity
  • intertia - the resistance an object has to change its state of motion 
  • distance - the length of the path a body follows when moving from one position to another
  • displacement - the shortest straight-line measurement between two points
  • speed - the rate of change of distance
  • velocity - the rate of change of displacement
  • acceleration and deceleration - rate of change of velocity 
  • momentium - mass x velocity 
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Newton's first law

  • law of intertia 
  • a force is needed to change a body's state of motion 
  • a body will continue in its state of rest or motion in a straight line unless compelled to change that state by external forces exerted upon it
  • moving objects will travel at a constant velocity - stationary objects will stay stationary 
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Newton's second law

  • law of acceleration
  • the magnitude and direction of applied force determines the magnitude and direction of acceleration given to a body 
  • force governs direction
  • force = mass x acceleration 
  • mass of performer stays contant 
  • the greater the force exertedon the ground, the greater the acceleration
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Newton's third law

  • law of action/reaction 
  • to every action force there is an equal and opposite reaction
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Forces

vertical forces

  • weight - the effect of gravity on the body 
  • ground reaction force - occurs when two bodies are in contact with each other

horizontal force

  • friction - two bodies in contact with eachother that have a tendency to slip or slide
  • air resistance 

net force

balanced force

unbalanced force

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Angular momentum

angular momentum = moment of inertia x angular velocity 

  • moment of inertia and angular velocity are inversley proportional 
  • angualr momentum is conserved 
  • angular velocity - how fast an object is spinning
  • moment of inertia - resistance of an object to rotate - dependent upn the mass of an object and the distribution of its mass around the axis of rotation 
  • mass closer to axis - moment of inertia decreases - angular velocity increases
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Impulse

  • impulse = force x time
  • impulse is also a change in momentum --> momentum = mass x velocity 
  • force x time = mass x velocity 
  • impulse can be used in sport to change speed
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Impulse in a race

start

  • negative impulse generated on footfall is less than the positive impulse generated on the push phase of the stride
  • positve greater than negative so net positive impulse - positive momentum - acceleration 

middle 

  • positive impulse from the push phase is the same as the negative impulse from footfall
  • zero net imupulse
  • no change in momentum - constant velocity 

end 

  • negative impulse of footfall is greater than the positive impulse of the push phase
  • negative net impulse
  • negative momentium - decelerating 
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Projectile motion

paraoblic curve

  • flight path of a projectile in the absence of air resistance
  • symmetrical, inverted U shape graph

components

  • horizontal and vertical

factors affecting range

  • height of release
  • angle of release
  • velocity of release
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Angle of release

  • release height = landing height --> optimum angle is 45
  • release height > landing height --> optimum angle less than 45
  • release height < landing height --> optimum angle more than 45
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SPECIALISED TRAINING

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Altitude training

partial pressure of oxygen decreases as altitude increases

adaptations

  • body produces EPO (erythropoietin)
  • more red blood cells 
  • greate oxygen transport
  • increased V02 max
  • increases myoglobin levels
  • increases the muscle's ability to buffer lactate 
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Disadvantages of altitude training

  • reduced partial pressure of oxygen means athletes are unable to train as hard
  • loss of fitness due to detraining effect
  • quicker exhaustation while at altitude
  • meaning aerobic performance deteroiates 
  • altitude sickness
  • dehydration
  • beneftis lost on return to sea level
  • expensive
  • increased lactate accumulation
  • social problems of moving from home

solution - live high train low 

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Glycogen loading

used for endurance sports - normally ony enough glycogen for 90 mins

orignal technqiue

  • 3 days of high intensity exercise with low carb diet - deplete glycogen stores
  • next 3 days reduce training intensity and increase carbs
  • supercompensation

changes

  • increase carb intake in the days approaching training whilst maintaing the usal tapering down of training will lead to high levels of muscle glycogen being stored

recent technique

  • 3 minute burst of high intensity exercise a day before competion 
  • immediatley followed by a 24 hour carb diet started less than 20 minutes after the exercise - carb window 
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advantages and disadvantages of glycogen loading

advantages 

  • increases stores of glycogen - supercompensation
  • delays fatigue and increases endurance
  • stops athletes hitting the wall

disadvantages

  • can interfere with training - want to taper
  • can interfere with diet and lead to weight gain - high carb diet increases water retention
  • heavy legged
  • lethargic 
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Thermoregulation

  • changes in bdoy temperature are detected by thermoreceptors
  • informatio is sent to the hypothalamus in the thermoregulatory centre 
  • triggers autonomic nervous system which triggers changes 

changes 

  • vasodilation - more blood to skin
  • radiation
  • conduction 
  • convection
  • increased sweat gland ativity 
  • rehydration 
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Why is an increase in body temperature a problem?

  • exercise/muscle contraction generates heat 
  • high core temperature
  • increased blood viscosity 
  • metabolic processes slowed down
  • unable to sweat efficiently
  • denaturation of enzymes so they don't work properly 
  • loss of electroyltes / dehydration
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How is thermoregulation achieved?

  • thermoreceptors detect temperature change and sends messgaes 
  • hypothalamus in the thermoregualtory control centre recieves messages
  • vasodilation - opening of blood vessels so blood travels closer to the skn
  • radiation - heat lost by infrared rays
  • conduction - heat lost from skin to air/object
  • evaporation - heat lost by liquid to vapour
  • heat retention - hairs raised
  • vascontstriction - closing of blood vessels
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Pylometric training

  • e.g. bounding
  • improves power

process

  • three phases : stretch shortening cycle
  • eccentric muscle contraction happens first
  • elastic energy is generated and stored
  • muscle spindle detects this and sends nerve impulses to the CNS
  • CNS inititates a stretch reflex
  • powerful concentric contraction occurs
  • stretch reflex stops overstretching of muscles avoiding injury 
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PNF stretching

process

  • muscle passivley stretched (may be done with the help of a partner)
  • target muscle stretched to full rage of movement
  • muscle then contracted isometrically against a resistance while in a stretched position for at least 10 secnds
  • muscle relax
  • stretch target muscle passivley again - increase in range or motion
  • CRAC - contract/relax/antagonist/contract

physioloigcal explanation

  • muscle spindle detets change in muscle fibre
  • causes stretch reflex - designed to prevent overstretching 
  • PNF overrides the stretch reflex
  • when the muscles relax autogenic inhibition occurs
  • allows greater range of movement than the initial stretch 
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Periodisation

dividing the year into training phases, normally based on Olympics

  • preparation phase - development of base level of ftiness
  • conditioning - quanity rather than quality 
  • competition phase - reifinement of skills - quality rather than quantity
  • tapering - decrease in intensity of training in order to prepare for a specific competition
  • peakin - making sure that both mind and body are at their best for a competiton
  • transition phase - active rest / out of season recovery period
  • macrocyle - long term training plan with a long term goal - often a single competiton
  • mesocyle - a goal based block of training sessions - period of 2 to 8 weeeks
  • microcyl - pattern of training sessions lasting a week
  • can plan for double periodisation
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Lactate sampling

a lactate sampler is used to take pin ***** blood samples and test for lactate accumulation

enables athletes to ensure training is at the correct intensity 

allows athletes to monitor improvements over time

measures OBLA which occurs at 4mmols

provides accurate and objective measurment

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Respiratory exchange ratio

  • ratio of carbon dioxide released compared to oxygen used by the body 
  • estimates use of fats and carbohydrates used during exercise
  • can tell if a performer is working anaerobically or aerobically i.e. using which energy system
  • RER close to 1 performer using carbohydrates - close to 0.7 using fats 
  • working closer to 1 - OBLA occurs quicker 
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PREPARATION AND TRAINING

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Creatine

Advantages

  • increases amount of PC stored in the muscles
  • allows the ATP/PC system to last longer
  • benefits short powerful movements/high intensity activities 

Disadvantages 

  • bloating
  • muscle cramps
  • slight liver damage 
  • mixed evidence to show positive results
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Herbal remedies

  • decrease body fat
  • elevate blood testosterone
  • increase muscle mass
  • enhance energy 
  • improve stamina 
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Herbal remedies

  • decrease body fat
  • elevate blood testosterone
  • increase muscle mass
  • enhance energy 
  • improve stamina 
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Protein supplements

Advantages 

  • enhance muscle repair and growth 
  • increase endurance 
  • increase muscle mass
  • may be used by vegetarians to supplement diet

Disadvantages

  • overuse puts strain on the kidneys and liver
  • may cause negative nitrogen balance which slows down muscle growth and can cause fatigue
  • not needed if you have a balanced diet
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Protein supplements

Advantages 

  • enhance muscle repair and growth 
  • increase endurance 
  • increase muscle mass
  • may be used by vegetarians to supplement diet

Disadvantages

  • overuse puts strain on the kidneys and liver
  • may cause negative nitrogen balance which slows down muscle growth and can cause fatigue
  • not needed if you have a balanced diet
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Sodium bicarbonate

'soda-loading'

advantages 

  • reduces the acidity in muscle cells
  • delays fatigue and allows the performer to continue exerercising at high intensity for longer
  • increases the buffering capacity of the blood, so neutralising the negative effects of lactic acid

disadvantages 

  • vomitting 
  • pain 
  • cramping
  • diarrhoea
  • bloating 
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Caffeine

advantages 

  • stimulant so increase mental altertness and reduces fatigue
  • improves reaction time
  • imrpoves the mobilisation of fatty acids in the body, this helps save muscle glycogen stores
  • benefits aerobic and anaerobic athletes

disadvantages 

  • risk of dehydration 
  • irritability 
  • insomnia 
  • anxiety 
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Effects of dehydration

  • water leaving the blood causes the blood to thicken 
  • reduction in blood flow to working muscles
  • heart has to work harder to move blood around the body - less oxygen avaliable to the muscles
  • slow reactin time
  • muscle fatigue
  • muscle crmaps
  • irregular heart beat 
  • disruption to removal of waste products / lactic acid build up 
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Effects of dehydration

  • water leaving the blood causes the blood to thicken 
  • reduction in blood flow to working muscles
  • heart has to work harder to move blood around the body - less oxygen avaliable to the muscles
  • slow reactin time
  • muscle fatigue
  • muscle crmaps
  • irregular heart beat 
  • disruption to removal of waste products / lactic acid build up 
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Ergogenic aids

  • EPO
  • Anabolic steroids
  • human growth hormone
  • beta blockers 
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EPO

a hormone that controls red blood cell production

  • increases haemoglbion levels which improves oxygen carrying capacity of the blood and this can increase the amount of work performed
  • blood clotting, stroke and maybe death 
  • endurance performers who need effective oxygen transport
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Anabolic steroids

  • aids protein storage, increases muscle size, decreases amount of fat in muscles, allows the athlete to train for longer at a highe intensity, faster recover time so train more frequently 
  • liver damage, acne, behavioural changes such as aggression and mood swings, shrinking testicles (males) and facial hair (females)
  • power athletes such as sprinters
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Anabolic steroids

  • aids protein storage, increases muscle size, decreases amount of fat in muscles, allows the athlete to train for longer at a highe intensity, faster recover time so train more frequently 
  • liver damage, acne, behavioural changes such as aggression and mood swings, shrinking testicles (males) and facial hair (females)
  • power athletes such as sprinters
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Human growth hormone

artificial growth hormone

  • increases muscle mass, decreases fat
  • diseases of the heart and nerves, glucose intolerance and high levels of blood fats 
  • sprinters, rugy players, endurance performers 
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Human growth hormone

artificial growth hormone

  • increases muscle mass, decreases fat
  • diseases of the heart and nerves, glucose intolerance and high levels of blood fats 
  • sprinters, rugy players, endurance performers 
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Beta blockers

a drug that blocks the release of chemicals such as adrenaline, helping a performer to calm down

  • decrease anxiety, steady nerves, imrpove accuracy 
  • tiredness due to low blood pressure and slower heart rate - affects aerobic capacity 
  • golf players, dart player, snooker players 
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SPORTS INJURIES

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Preventing sports injuries

  • clothing 
  • protective equipment
  • taping, straping and bracing 
  • footwear
  • warm up and cool downs
  • training programme with rest days - no over training
  • modify techniques
  • strength and conditioning programme
  • correct diet
  • ice baths 
  • massages 
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Causes of sports injuries

intrinsic 

  • gender 
  • age 
  • body mass and composition
  • muscle strengths and weakness (general fitness)
  • lack of flexibility 
  • skeletal features

extrinsic 

  • training colume 
  • techniqiue 
  • playing surfaces
  • wrong clothing or footwear
  • environmental conditions 
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RICE

rest/ice/compression/elevation

  • rest as soon as injury occurs
  • ice: 10-15 mins with ice, 20 mins off and repeat - vasoconstriction reduces internal bleeding and the flow of fluids from damaged cells (controlling swelling) - wrap ice in towel to avoid frostbite
  • compression: taping or strapping the area - reduces of helps control swelling, swelling delays healing - fluid leaks from an injury into surrounding tissue
  • elevation - raise the injured part (if possible above the heart) - gravity sends fluids back towards the body core, thus reducing damage caused by swelling 
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DOMS

  • delayed onset muscle soreness, felt as tenderness and pain within a muscle

caused by:

  • excess lactic acid (mainly from eccentric muscle activity)
  • micro-tears and the resuling inflammation in muscle tisude

reduce DOMS:

  • active warm up and cool down 
  • graduallly increase intensity of workload
  • put eccentric contractions later on in the session 
  • massage 
  • ice baths 
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Hyperbaric chambers

  • reduce recovery time for an injury 
  • chamber is pressurised 
  • delivers oxygen at a high pressure
  • pressure increases the amount of oxygen breathed in - more oxygen can diffuse into the injured area
  • dissolved oxygen reduces swelling and stimulates the body's cells to repair
  • approx 2.5 more oxygen than normal
  • haemoglobin is fully saturated 
  • excess ozygen dissolved in plasma
  • reaches parts of the body not normally saturated 
  • increased white blood cell activity at injured site
  • increased blood supply 
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Oxygen tents

  • hypoxic tents
  • elite athletes may sleep in them overnight
  • tents stimulate effects of high altitude by providing a low oxygen environment. oxygen depletion causes production of higher heamoglobin levels - improves the oxygen carrying capactiy of the body - improves VO2 max
  • does not make a difference to the speed of the healing process, just means that individual performers retain fitness after recovering from injury 
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Ice baths

  • 5-10 minutes
  • cold water causes vasoconstriction - blood vessels tighten- drains blood out of legs 
  • when the athletes leaves the bath vasodilation occurs, blood vessels relax, legs fill up with fresh blood, the blood that leaves the legs takes away the lactic acid 
  • fresh blood invigorates the muscles with oxygen to help the cells function better
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