Nutrition and Physical Performance

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Unit 27

• Nutrition and Physical Performance

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True or False

• The diet an athlete consumes affects energy
  substrate availability to muscles during
  exercise.
• True. Carbohydrate and fat availability to
  muscles during exercise varies based on usual
  diet.
• Carbohydrate loading is a waste of time.
• False. Carbohydrate loading can work for
  endurance events if combined with the right
  training program.

3
True or False

• Commercially available protein powders and bars
  build muscle if consumed while training.
• False. Protein powders or bars have not been
  found to increase muscle mass whether consumed
  during training or not.
• Scientists cant explain why, but bee pollen
  actually improves physical performance.
• False. In bees, maybe- in humans, absolutely not.

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Factors affecting physical performance

• Genetics
• Cannot be controlled or changed by the athlete
• Training
• Is a basic truth, recognized by all athletes
• Nutrition
• Often ignored or misunderstood
• Only 1 in 10 coaches have had basic nutrition
  class but nearly all regularly dispense nutrition
  information

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Components of energy formation during exercise

• Glucose from the muscle and liver glycogen
• Fatty acids released from fat stores
• How much of each is used depends on intensity and
  duration of exercise and how well body can
  deliver each with oxygen to the muscles.
• Muscles form ATP from ADP ATP energy

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Anaerobic energy formation

• Glucose and glycogen form ATP without oxygen
• Anaerobic without oxygen
• Fuels intense muscular work
• Creatine phosphate converts ADP to ATP
• Creatine stores are limited decrease rapidly
  during intense exercise
• Glucose to pyruvate to lactate
• Back to pyruvate if oxygen becomes available
• Pyruvate oxygen energy

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How ATP is formed for muscular movement
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Aerobic energy formation

• Pyruvate and fatty acids to ATP requires oxygen
• More ATP delivered by breakdown of fat than by
  glucose
• Rate of energy formation from fatty acids is four
  times slower
• Muscle cells can continue to produce energy from
  fatty acids as long as delivery of oxygen from
  lungs and circulation is sufficient

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Glycogen

• Fat for low to moderate intensity activities
• Glucose for high intensity activities
• Glycogen necessary for endurance activities
• Glycogen stored in the muscles and liver
• Less abundant than fat
• Intense physical activity limited by amount of
  glycogen. When its gone, you hit the wall. If
  you continue, you bonk or become dizzy
  or shaky or pass out

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Increasing Glycogen

• Athletes consuming the typical U.S. diet have
  enough glycogen stores to fuel continuous,
  intense exercise for one to two hours.
• This can be increased by loading muscles with
  glycogen.

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Carbohydrate loading

• Increase carbohydrate intake to 60-70 of total
  calories for three days prior to the event
• Increase exercise, then rest the day before the
  event
• Carbohydrate loading is limited- muscles can only
  hold so much glycogen
• Not all athletes can tolerate carbohydrate
  loading- may cause stiff, heavy feeling from
  extra glycogen

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Protein needs

• Most athletes require only their RDA for protein
• Strength training may need up to 15 gm extra
  protein daily however, most Americans already
  consume extra protein.

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Pre-event food choices

• Carbohydrates
• Digested faster than proteins or fats
• Enter the blood stream primarily as glucose
• Fluids
• Athletes should snack between events

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Hydration

• Muscular activity produces heat
• Heat is collected from the muscles and released
  through the blood and sweat
• Hot, humid conditions require more fluids
• 2 cups water 15-20 minutes before events will
  keep you hydrated for short events
• Replace ½ to 1 cup water every 15-20 minutes of
  exercise, up to one hour of activity
• Events longer than one hour require additional
  carbohydrate, electrolytes

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Dehydration

• Any amount of dehydration impairs physical
  performance
• Dehydration can lead to heat exhaustion or heat
  stroke
• Heat exhaustion- replace fluids
• Heat stroke- requires emergency medical care
• Hyponatremia- loss of sodium during very long
  events
• Replace sodium during very long events

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Sports Drinks

• Sports drinks that contain 4-8 carbohydrate and
  50 mg sodium/8 oz and other electrolytes improve
  endurance and hydration status during prolonged,
  intense events that last over an hour.
• Drink in addition to water
• High sugar drinks dont help. Neither does
  alcohol or coffee or tea

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Body fat and weight

• Athletes tend to be concerned about their weight
  and are generally leaner than the general
  population.
• If body fat is too low, it can cause serious
  health problems.
• Women- loss of menstrual cycle, low bone density
  and osteoporosis later in life
• Men- loss of testosterone, which may lead to loss
  of muscle, other health problems

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Wrestling and weight cycling

• Making weight is important to wrestlers
• Most wrestlers will cut 1-20 lbs in a few days,
  50-100 times during a high school or college
  career
• Fasting, sweating in saunas or rubber suits,
  vomiting after meals are used to lose weight
  before weigh-in
• After the match, wrestlers may binge and regain
  the weight

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Wrestling

• Fasting before weigh-in dramatically reduces
  glycogen stores
• Withholding fluids or losing water through
  sweating puts the wrestler at risk of dehydration
• AMA recommends that weight should be determined
  after 6 weeks of training and eating a normal diet

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Iron status

• Iron-deficiency anemia decreases endurance
• Less iron less hemoglobin less oxygen to the
  cells
• Reduced oxygen lowers the amount of energy
  muscles can produce
• May be other reasons besides oxygen delivery
• Women at greater risk than men

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Ergogenic aids

• Athletes have always been looking for a
  competitive edge
• Relatively few of the products work
• Being sold as dietary supplements means they
  dont have to be tested
• Some aids pose serious health risks

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Ergogenic aids

• Amphetamines
• Androgenic anabolic steroids
• Bee pollen
• Boron
• Branched chain amino acids
• Caffeine
• Carnitine
• Cocaine
• Creatine

• DHEA, AD
• Ephedra (ma huang)
• EPO
• GBL
• Ginseng, Siberian
• HGH
• Insulin
• Protein powders
• Vitamin and mineral supplements

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Genetics, Training, and Nutrition are the real
keys to physical performance