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

2. 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

3. 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

4. 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

5. 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

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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

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

18. 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

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

20. 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

21. 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

22. 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 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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