Jan Roscoe Publications

1
Jan Roscoe Publications

AQA ExaminationsAS Level Sport and Physical
Education 2580 AS Module Unit 1
PHED1 Opportunities for and the effects of
leading a healthy and active lifestyle Section
A Applied Exercise Physiology Part 2 Nutrition
2
INDEX

• 3 - METABOLISM
• BASAL METABOLIC RATE (BMR) / TOTAL METABOLIC
  RATE
• 4 - A BALANCED DIET
• BALANCED DIET / CARBOHYDRATE / FATS / PROTEIN
• 5 - THE NEED FOR A BALANCED DIET
• 6 - A FOOD PYRAMID
• 7 - STORAGE AND RELEASE OF ENERGY / FOOD FUELS
• 8 - COMPARISON OF DAILY ENERGY INTAKE
• 9 - DIFFERENT DIETS FOR DIFFERENT ATHLETES
• 10 - PROTEIN REQUIREMENTS FOR DIFFERENT ATHLETES
• 11 - VITAMINS / MINERALS / SUPPLEMENTS / WATER
  REQUIREMENTS
• 12 - NUTRITION AND EXERCISE
• PRE / DURING / POST COMPETITION
• 13 - NUTRITION AND EXERCISE
• DIETARY MANIPULATION / DURING-POST EXERCISE
• 14 - WATER BALANCE
• 15 - OBESITY
• 17 - OBESITY AND ENERGY BALANCE
• 19 - WEIGHT LOSS PLAN

3
METABOLISM

• ENERGY METABOLISM
• total intake of food sufficient to supply enough
  energy to
• keep cells alive
• keep systems working
• meet demands of life
• BASAL METABOLIC RATE (BMR)
• this is the least rate of energy usage needed to
  carry out basic body functions
• measured after lying down after 8 hours sleep /
  12 hours fasting
• TOTAL METABOLIC RATE
• sum of BMR energy required for all daily
  activities
• total average energy usage for 18 year olds in
  the USA is
• females 8,000 kj per day males 12,000 kJ per
  day.

4
A BALANCED DIET

• A BALANCED DIET
• contains proportions of
• carbohydrates, fats and proteins
• minerals, vitamins, water and roughage (fibre)
• needed to maintain good health
• CARBOHYDRATE - 60
• principal energy giver
• FATS - 20-25
• storage of energy
• another source of energy
• carrier of fat soluble vitamins
• PROTEIN - 10-15
• essential for growth, body building and repair

5
THE NEED FOR A BALANCED DIET

• ENERGY BALANCE
• when energy input (via food) is equal to energy
  output (via metabolism including exercise)
• a neutral energy balance is achieved
• ENERGY INTAKE ENERGY OUTPUT
• as a result of this body weight will remain
  constant
• ACHIEVING A BALANCED DIET
• decrease dietary fat, especially saturated fats
• decrease the amount of salt (sodium)
• increase complex carbohydrates
• increase minerals such as calcium and iron
• iron is especially important for females

6
A FOOD PYRAMID
fat, butter, margarine, cooking oil
fats
milk, cheese, yoghurt, eggs, red meat, chicken,
fish
protein and some fat
vegetables and fruit - 5 per day
fibre, vitamins minerals
carbohydrate and fibre, the bulk of food eaten
cereal, pasta, bread, biscuits, cake,
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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 Krebs cycle in aerobic respiration

8
COMPARISON OF DAILY ENERGY INTAKE

• Activity daily energy daily energy
• intake kJ intake kJ
• females males
• Tour de France 25000
• Triathlon 23000
• Rowing 13000 14900
• Swimming 8800 15300
• Hockey 9000 13800
• Soccer 14600
• Running 8800 13200
• Gymnastics 7100
• body building 7000 13800
• average USA
• 18 year olds 8000 12000

• figures are approximate and for elite athletes
• Int.J Sports Med 19891053

• MALE FEMALE DIFFERENCES
• note that these differences can be mostly
  accounted for by differences in body mass, with
  the values of energy expenditure per day per
  kilogramme of body mass would be similar

9
DIFFERENT DIETS FOR DIFFERENT ATHLETES

• BALANCED DIET
• a balanced diet from a regular food intake will
  provide the nutrient requirements for all
  sportspeople
• CHO REQUIREMENT
• a high CHO diet significantly improves
  performance
• immediate post-exercise CHO supplements, and high
  glycemic index (GI) foods such as bananas and
  raisins
• will start reloading depleted muscle glycogen
  stores
• CARBOLOADING
• carboloading can augment endurance performance in
  events lasting longer than 90 minutes by
  increasing muscle glycogen stores above normal
  levels
• FAT REQUIREMENTS
• fat intake should be restricted for both power
  and endurance athletes
• except for power events such as sumo wrestling

10
PROTEIN REQUIREMENTS FOR DIFFERENT ATHLETES

• ENDURANCE ATHLETES
• the recommended protein intake is 1.2 - 1.4 grams
  per kilogram of body mass per day
• STRENGTH AND POWER ATHLETES
• need additional protein
• 1.4 - 1.8 grams per kilogram of body mass per day
• this need for extra protein is because after
  heavy resistance training the rate of protein
  breakdown and resynthesis is greater
• because of muscle hypertrophy

11
VITAMINS / MINERALS/ SUPPLEMENTS / WATER
REQUIREMENTS

• VITAMINS AND MINERALS
• a regular intake of vitamins and minerals is
  required for all performers
• research has shown that a normal well balanced
  diet provides all necessary vitamins and minerals
  to support elite performances
• dietary fibre is also needed at a balanced level
  and must not be neglected for the elite performer
• SUPPLEMENTS
• glutamine has been shown to help immune systems
  after exercise
• creatine has been shown to increase muscle
  creatine levels to help sustain power output in
  power events
• a balanced normal diet will contain sufficient
  glutamine and creatine for this
• amino acid / CHO supplementation is often taken
  in liquid form following exercise - see next
  slide
• WATER
• exercise is thirsty work, see the following later
  slides for details

12
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
• FOOD / FLUID INTAKE DURING OR IN BETWEEN EXERCISE
• water loss of as little as 2 to 3 can reduce
  performance
• hence an isotonic sports drink including very
  diluted sodium and glucose content
• prevents dehydration and supplements energy
  reserves
• or just take water
• 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

13
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

14
WATER BALANCE

• WATER BALANCE
• (water is 60 of total body mass)
• water balance at rest
• water loss occurs via evaporation excretion,
  with the majority lost as urine
• water intake depends on climate and body mass
• water balance during exercise
• more water produced during tissue respiration
• water loss mainly as sweat determined by external
  temperature, body mass and metabolic rate and
  intensity of exercise
• this also includes mineral loss which must be
  replaced
• increased water loss via expired air due to
  increased breathing
• age and fitness / acclimatisation levels also
  affect water loss
• kidneys decrease urine flow in an attempt to
  decrease dehydration
• during a marathon 6-10 of body water content is
  lost, hence the need for water intake during
  exercise
• this means that during 1 hours exercise an
  average person could expect to lose around 1
  litre of fluid
• and even more in hot conditions
• this could represent as much as 2 litres an hour
  in warm / humid conditions

15
OBESITY

• OVERWEIGHT
• a body weight that exceeds the norm or standard
  weight for a particular
• height
• frame size
• gender
• OBESITY
• a surplus of adipose tissue resulting from
  excessive energy intake relative to energy
  expenditure
• males - body fat greater than 25
• females - body fat greater than 35

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OBESITY
17
OBESITY AND ENERGY BALANCE

• CAUSE OF OBESITY
• the main cause of obesity is a positive energy
  balance
• ENERGY INTAKE gt ENERGY OUTPUT
• or more food than exercise
• excess carbohydrate (CHO) is stored as glycogen
• when glycogen stores are filled, CHO together
  with excess fat intake, is converted to fatty
  acids and glycerol, and then is stored as
  triglycerides or fat in adipose tissue
• adipose tissue is situated around major organs
  such as the heart and stomach, underneath the
  skin, and in skeletal muscle
• upper body obesity poses a significantly greater
  risk to disease
• health conditions such as coronary heart disease
  and hypertension
• with an increased risk of mortality and morbidity

18
OBESITY AND ENERGY BALANCE

• CONTROLLING OBESITY
• the only method of controlling obesity is to
  shift the energy relationship so that energy
  output exceeds energy intake known as a
  negative energy balance and expressed as
• ENERGY OUTPUT gt ENERGY INTAKE
• a negative energy balance can be achieved with
  the help of a Weight Loss Plan
• WHAT IS A GOOD LEVEL OF FAT?
• An minimum requirement which would allow full
  body functions body fat percentage for men is
  between 2 and 3 and for women between 8 and
  12
• normally only healthy elite athletes attain these
  percentages
• relative body fat is a major concern of
  sportspeople
• achieving a desired weight goal can lead to
  clinical eating disorders such as anorexia
  nervosa
• caused by a person restricting food intake to
  levels well below energy expenditure
• it is important to have a diet that maintains
  appropriate weight and body composition to
  maximise physical performance

19
WEIGHT LOSS PLAN
20
ASSESSING OBESITY

• BODY COMPOSITION
• relative percentage of muscle, fat and bone
• measured using
• skinfold measurements using the J-P nomogram
• body composition scales using bioelectrical
  impedance analysis
• underwater weighing

• BODY MASS INDEX (BMI)
• measures the relationship between weight and
  height
• measured using
• BMI weight in kilogrammes
• square of body height in metres
• a person 1.83m tall weighing 110 kg has
• BMI 110 110 32.8
• 1.832 3.35