Edexcel Examinations A Level Physical Education A 9536 Unit 6 : Section A part 2 Scientific Principles of Exercise and Performance

INDEX Index 3 - MUSCLE FATIGUE DEPLETION OF ENERGY STORES / FIBRE TYPE / METABOLIC ACCUMULATION 4 - MUSCLE FATIGUE INTERRUPTION OF NEUROMUSCULAR EVENTS ANTICIPATED FATIGUE / BODY FLUID BALANCE 5 - MUSCLE FATIGUE - FLUID INTAKE 6 - EXCESS POST-EXERCISE OXYGEN CONSUMPTION (EPOC) FACTORS CONTRIBUTING TO EPOC 7 - THE RECOVERY PROCESS EPOC / AIM OF RECOVERY PROCESS OXYGEN DEFICIT / DEBT 8 - THE RECOVERY PROCESS THE ALACTACID COMPONENT 9 - THE RECOVERY PROCESS IMPLICATIONS FOR INTERVAL TRAINING / EFFECTS OF TRAINING 10 - THE RECOVERY PROCESS LACTACID OXYGEN RECOVERY / RECOVERY 11 - THE RECOVERY PROCESS - FATE OF LACTIC ACID / THE LACTATE SHUTTLE / BUFFERING 12 - EFFECT OF COOL-DOWN ON LACTIC ACID REMOVAL REMOVAL OF LACTIC ACID FOLLOWING EXERCISE 13 - RECOVERY OF BODY STORES RESTORATION OF MUSCLE GLYCOGEN / MYGLOBIN STORES 14 - IMPLICATIONS FOR INTERVAL TRAINING OF LACTACID RECOVERY 15 - FUEL FOR EXERCISE A BALANCED DIET / CARBOHYDRATE / FATS / PROTEIN 16 - STORAGE AND RELEASE OF FOOD FUELS CARBOHYDRATES / GLUCOSE / FATS / FATTY ACIDS 17 - FOOD FUEL USAGE DURING EXERCISE DURING HIGH INTENSITY EXERCISE / AT REST 18 - EXERCISE AND FOOD FUEL USAGE FOOD FUEL USAGE AT REST AND DIFFERNET INTENSITY AND DURATION 19 - FOOD FUEL UTILISATION DURING EXERCISE 20 - FOOD FUEL USAGE FOR AEROBIC ACTIVITY FOOD FUEL USAGE / EXERCISE INTENSITY / DURATION 21 - FOOD FUEL USAGE FOR AEROBIC ACTIVITY SOURCES OF FUELS 22 - NUTRITION AND EXERCISE - CARBOLOADING 23 - NUTRITION AND EXERCISE - CARBOLOADING IMPORTANCE OF HIGH GLYCOGEN CONTENT 24 - NUTRITION AND EXERCISE PRE / POST / DURING COMPETITION NUTRITION 25 - WATER BALANCE 26 - NUTRITION AND EXERCISE - FLUID INTAKE 27 - NUTRITION AND EXERCISE - DIETARY MANIPULATION 28 - FOOD FUEL UTILISATION DURING ANAEROBIC ACTIVITY HIGH INTENSITY 8 seconds / 60 seconds 29 - RESPONSE TO EXERCISE and TRAINING on the ENERGY SYSTEMS - and your IPP

MUSCLE FATIGUE MUSCLE FATIGUE a reduction of muscular performance Fatigue and the Recovery Process MUSCLE FATIGUE MUSCLE FATIGUE a reduction of muscular performance an inability to maintain expected power output DEPLETION OF ENERGY STORES depletion of PC and muscle / liver glycogen stores fatigue in marathon runners is due to depletion of muscle glycogen in both ST and FT fibres FIBRE TYPE FT muscle fibres have low aerobic capacity therefore quickly fatigue during maximal activity METABOLIC ACCUMULATION accumulation of lactic acid and CO2 in muscle cells hence increase in H+ ions (decrease in pH) inhibits enzyme action (both aerobic and anaerobic) required for ATP regeneration

MUSCLE FATIGUE MUSCLE FATIGUE is caused by : Fatigue and the Recovery Process MUSCLE FATIGUE MUSCLE FATIGUE is caused by : depletion of energy stores accumulation of metabolites (lactic acid / CO2) low energy stores in certain fibre types which in turn cause : INTERRUPTION OF NEUROMUSCULAR EVENTS decrease in Calcium ion (Ca++) availability at motor end-plate and failure of Acetylcholine generation mechanism which delay release and synthesis of Acetylcholine which reduces transmission of action potential to skeletal muscle fibre OTHER CAUSES : ANTICIPATED FATIGUE the CNS might perceive fatigue prior to physiological fatigue BODY FLUID BALANCE fluid loss decreases plasma volume which reduces blood pressure hence a reduction in blood flow to skin and muscles hence the heart has to work harder, body temperature rises, hence fatigue occurs hence fluid intake is important during endurance activities

MUSCLE FATIGUE FLUID INTAKE Fatigue and the Recovery Process MUSCLE FATIGUE FLUID INTAKE water loss of as little as 2% to 3% can reduce performance the graph shows how heart rate is affected by fluid intake during prolonged exercise hence an isotonic sports drink including glucose and essential electrolytes prevents dehydration and supplements energy and electrolytes lost through sweating or just take water hypertonic sports drink immediately after exercise has finished begins replenishment of blood glucose, glycogen store and essential electrolytes

EXCESS POST-EXERCISE OXYGEN CONSUMPTION (EPOC) Fatigue and the Recovery Process EXCESS POST-EXERCISE OXYGEN CONSUMPTION (EPOC) FACTORS CONTRIBUTING TO EPOC

THE RECOVERY PROCESS EXCESS POST-EXERCISE OXYGEN CONSUMPTION (EPOC) Fatigue and the Recovery Process THE RECOVERY PROCESS EXCESS POST-EXERCISE OXYGEN CONSUMPTION (EPOC) this is the excess O2 consumed following exercise needed to provide the energy needed to resynthesise ATP used and remove lactic acid created during previous exercise EPOC has two components : ALACTIC LACTIC AIM OF RECOVERY PROCESS to replace ATP and glycogen stores as soon as possible OXYGEN DEFICIT the difference between the O2 required during exercise and the O2 actually consumed during the activity OXYGEN DEBT the graph shows the relationship between O2 consumption and the time before, during and after exercise

THE RECOVERY PROCESS THE ALACTACID COMPONENT Fatigue and the Recovery Process THE RECOVERY PROCESS THE ALACTACID COMPONENT involves the conversion of ADP back into PC and ATP this is known as restoration of muscle phosphagen and is a very rapid process (120 seconds to full restoration) size 2 to 3.5 litres of O2 this is achieved via THREE MECHANISMS : aerobic conversion of carbohydrates into CO2 and H2O to resynthesise ATP from ADP and Pi some of the ATP is immediately utilised to create PC using the coupled reaction : ATP + C ---> ADP + PC small amount of ATP is resynthesised via glycogen producing small amounts of lactic acid

THE RECOVERY PROCESS IMPLICATIONS FOR INTERVAL TRAINING Fatigue and the Recovery Process THE RECOVERY PROCESS IMPLICATIONS FOR INTERVAL TRAINING if there is only a short interval between bouts of exercise level of phosphagen stores gradually reduces EFFECTS OF TRAINING ON THE ALACTACID COMPONENT increase ATP and PC stores in muscle cells improved ability to provide O2 therefore increase in possible size of alactic component

THE RECOVERY PROCESS LACTACID OXYGEN RECOVERY Fatigue and the Recovery Process THE RECOVERY PROCESS LACTACID OXYGEN RECOVERY high intensity exercise up to 60 seconds creates lactic acid oxygen is needed to remove this lactic acid the process begins to restore muscle and liver glycogen RECOVERY the process is relatively slow full recovery takes up to 1 hour relatively large amounts of lactic acid (15 to 20 times the resting value of 1 to 2 mmol litre-1) are produced during high intensity exercise

THE RECOVERY PROCESS FATE OF THE LACTIC ACID Fatigue and the Recovery Process THE RECOVERY PROCESS FATE OF THE LACTIC ACID oxidation into CO2 + H2O 65% conversion into glycogen 20% then stored in muscle and liver (Cori cycle) conversion into protein 10% conversion into glucose 5% THE LACTATE SHUTTLE during the recovery process after intense execise a small proportion of the lactic acid produced is recycled back into glucose in the muscle cell this is the reverse process to glycolysis requiring energy from ATP breakdown BUFFERING A blood buffer is a chemical substance which resists abrupt changes in hydrogen ion (H+) concentration example : when H+ concentration increases as a result of intense exercise H+ reacts with oxyhaemoglobin (buffer) to form haemoglobinic acid these ions are released when H+ concentration falls

EFFECT OF COOL-DOWN ON LACTIC ACID REMOVAL Fatigue and the Recovery Process EFFECT OF COOL-DOWN ON LACTIC ACID REMOVAL REMOVAL OF LACTIC ACID FOLLOWING EXERCISE cool-down continues to provide oxygen to skeletal muscle which therefore enhances oxidation of lactic acid and ensures that less lactic acid remains in tissue and there is less muscle soreness

RECOVERY OF BODY STORES Fatigue and the Recovery Process RECOVERY OF BODY STORES RESTORATION OF MUSCLE GLYCOGEN STORES short duration high intensity exercise, restoration of glycogen takes up to 2 hours prolonged low intensity aerobic exercise, restoration can take days a high carbohydrate diet speeds up the glycogen recovery process there is a need for the athlete to restore stores as soon as possible after activity example : a high CHO loaded drink immediately following exercise MUSCLE MYOGLOBIN an iron protein molecule located in skeletal muscle (similar to haemoglobin) serves as a storage site for O2 has a temporary but greater affinity for O2 acts as a carrier of O2 from HbO2 (in blood) to mitochondria (in muscle cell) important in high intensity exercise RESTORATION OF MYOGLOBIN myoglobin is reoxygenated within 2 minutes

IMPLICATIONS FOR INTERVAL TRAINING OF LACTACID RECOVERY Fatigue and the Recovery Process IMPLICATIONS FOR INTERVAL TRAINING OF LACTACID RECOVERY INTERVAL TRAINING when planning training sessions, rates of recovery must be take into account recovery between bouts of exercise is dependent on heart rate values as heart rate (HR) falls during recovery, its value is a measure of lactacid recovery therefore repeating an exercise bout may not be possible until HR has fallen by a certain amount active recovery / cool-down speeds up removal of lactic acid variance in intensity of workload in sessions doesn’t always stress the lactic acid system

FUEL FOR EXERCISE A BALANCED DIET contains proportions of : Fatigue and the Recovery Process FUEL FOR EXERCISE A BALANCED DIET contains proportions of : carbohydrates, fats and proteins minerals, vitamins, water and roughage (fibre) needed to maintain good health CARBOHYDRATE - 55% principal energy giver FATS - 30% storage of energy another cource of energy carrier of fat soluble vitamins PROTEIN - 15% essential for growth, body building and repair

STORAGE AND RELEASE OF FOOD FUELS Fatigue and the Recovery Process STORAGE AND RELEASE OF FOOD FUELS CARBOHYDRATES glucose is absorbed in the small intestine GLUCOSE is utilised as fuel in the liver then stored as liver glycogen transported as glucose in the blood to other tissues (for example skeletal muscle) used as an immediate source of energy or converted and stored as muscle glycogen FATS absorbed as fatty acids or glycerol in the small intestine FATTY ACIDS utilised as fuel in the liver stored as triglycerides in adipose tissue or skeletal muscle recalled from fat deposits to the liver converted to glucose (this is a slow process) enters the Kreb’s cycle in aerobic respiration

FOOD FUEL USAGE DURING EXERCISE Fatigue and the Recovery Process FOOD FUEL USAGE DURING EXERCISE DURING HIGH INTENSITY EXERCISE AT REST

EXERCISE AND FOOD FUEL USAGE Fatigue and the Recovery Process EXERCISE AND FOOD FUEL USAGE FOOD FUEL USAGE dependent on exercise intensity and duration AT REST ATP utilisation slow a mixture of fats and carbohydrates INTENSITY HIGH / DURATION SHORT rapid and immediate increase in ATP usage PC provides ATP resynthesis muscle and liver glycogen stores used lactic acid produced INTENSITY LOW / DURATION LONG oxidation of a mixture of carbohydrates and fats the longer the exercise the bigger the proportion of ATP regenerated from fats

FOOD FUEL UTILISATION DURING EXERCISE Fatigue and the Recovery Process FOOD FUEL UTILISATION DURING EXERCISE

FOOD FUEL USAGE FOR AEROBIC ACTIVITY Fatigue and the Recovery Process FOOD FUEL USAGE FOR AEROBIC ACTIVITY FOOD FUEL USAGE this depends on : EXERCISE INTENSITY EXERCISE DURATION AT REST ATP utilisation is slow a mixture of fats and carbohydrates is used to resynthesise ATP FOR LOW INTENSITY LONG DURATION AEROBIC ACTIVITY usage of a variety of fuels but mainly the oxidation of a mixture of CHO and fats the longer the exercise the bigger the proportion of ATP resynthesis provided by fats

FOOD FUEL USAGE FOR AEROBIC ACTIVITY Fatigue and the Recovery Process FOOD FUEL USAGE FOR AEROBIC ACTIVITY SOURCES OF FUELS main source of CHO for muscular energy during exercise is glucose derived from stored muscle and liver glycogen lack of CHO fuel is the limiting factor for aerobic endurance performance main source of fat for muscular energy during exercise is free fatty acids (FFA) derived from triglycerides stored as adipose tissue under the skin and in muscle tissue triglycerides break down into FFA for entry into the aerobic energy system proteins become a significant source of energy only in extreme conditions when CHO and fats are depleted

NUTRITION AND EXERCISE Fatigue and the Recovery Process NUTRITION AND EXERCISE CARBOLOADING 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 Carbohydrate loading (new technique after Williams 1998) Endurance taper taper taper taper taper taper training training training training training training training day 1 day 2 day 3 day 4 day 5 day 6 day 7 race normal moderate---------------------- high ---------------------------------- diet CHO diet CHO diet this technique omits the glycogen depletion phase associated with earlier methods

NUTRITION AND EXERCISE Fatigue and the Recovery Process NUTRITION AND EXERCISE CARBOLOADING THE IMPORTANCE OF HIGH GLYCOGEN CONTENT IN MUSCLE BEFORE A MARATHON RACE the graph shows that a runner’s time would increase by more than 10 minutes in a 2 hour run if muscle glycogen is at 50% of its maximum possible the effect of reduced muscle glycogen begins to be felt at the 1 hour mark

NUTRITION AND EXERCISE Fatigue and the Recovery Process NUTRITION AND EXERCISE DIETARY MANIPULATION PRECOMPETITION NUTRITION fluids for hydration light complex CHO such as pasta / wholemeal bread at least 3 hours before activity fruit (banana) contains complex CHO and small amounts of glucose effect is to provide the slow release of blood glucose and reduce hunger sensations POST COMPETITION / TRAINING NUTRITION hypertonic sports drink immediately after exercise has finished begins replenishment of blood glucose and glycogen store a high CHO meal within 15 minutes of exercise ending continues glycogen replenishment

WATER BALANCE WATER BALANCE Energy Sources WATER BALANCE WATER BALANCE excessive loss of fluid impairs performance as blood plasma volume decreases and body temperature rises extra strain is placed on the heart, lungs and circulatory system which means that the heart has to work harder to pump blood around the body

NUTRITION AND EXERCISE Fatigue and the Recovery Process NUTRITION AND EXERCISE FLUID INTAKE DURING OR IN BETWEEN EXERCISE water loss of as little as 2% to 3% can reduce performance the graph shows how heart rate is affected by fluid intake during prolonged exercise hence an isotonic sports drink including very diluted sodium and glucose content prevents dehydration and supplements energy reserves or just take water

NUTRITION AND EXERCISE Fatigue and the Recovery Process NUTRITION AND EXERCISE DIETARY MANIPULATION the following graph shows the influence of dietary carbohydrate on muscle glycogen stores repeated daily exercise of 2 hours is followed by a either a high CHO or low CHO diet on a low CHO diet, muscle fatigue would be considerably greater accumulating over a period of days

FOOD FUEL UTILISATION DURING ANAEROBIC ACTIVITY Fatigue and the Recovery Process FOOD FUEL UTILISATION DURING ANAEROBIC ACTIVITY ENERGY SYSTEMS HIGH INTENSITY MAXIMAL WORK FOR LESS THAN 8 seconds the PC alactic energy system provides the majority of ATP resynthesis for this period food fuels used are direct use of PC stored in the muscle cell then those involved in the oxygen recovery phase after exercise which is an aerobic process, and inputs food fuel from mostly CHO and some fats HIGH INTENSITY WORK FOR UP TO 60 seconds (STRENGTH ENDURANCE) the lactic acid energy system provides the bulk of ATP for this period food fuels used directly are muscle glycogen via glycolysis

RESPONSE TO EXERCISE and TRAINING on the ENERGY SYSTEMS - and your IPP Physiological Adaptations RESPONSE TO EXERCISE and TRAINING on the ENERGY SYSTEMS - and your IPP YOUR PEP and TRAINING RESULTS YOUR PEP students are required to plan, perform, report and evaluate their physical activity which will form the basis of their personal exercise plan (PEP) THE RESULTS AND YOUR IPP the PEP and the outcomes of the physical activity are to be recorded in the student’s individual performance portfolio (IPP) students should analyse their performance in terms of : explaining short-term effects of exercise in terms of energy systems explaining physiological adaptations observed in their own activity explain how these adaptations enhance performance this is in addition to the recording of the results of fitness tests integrated into unit 3 which could be a means of assessing whether adaptations have occurred or not