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SPORT NUTRITIONWeek 12
What you need to know…
• When and why are CHO and protein important?
• How does a diet need to change for different sports?
• What should be eaten before, during and after exercise?
• What are the benefits of dietary strategies?– CHO loading, creatine, caffeine,
hydration, minerals
Carbohydrate (CHO)
• Major fuel source– Extended, high intensity– Prolonged, sub-maximal
• Limited capacity to store
• Important to eat before, during and after exercise
• The more physical activity the more CHO required to be consumed
Protein
• Recovery and __________ of body tissue damaged during exercise
• Athletes __________ need extra protein in diet
• Normal diet provides sufficient protein
Preparing for Competition
• Specific nutritional strategies will help the athlete to reach optimal performance
• The athlete needs to avoid nutrition related fatigue– Depletion of __________– Hypoglycemia (low blood
glucose)– _____________– Low blood sodium levels
Short Duration Sports
• Glycogen depletion does not normally occur
• Little need to increase __________ intake
• Important to restore glycogen levels in __________
Team Sports
• Slight increase in CHO intake in 24-36 hours before competition can be beneficial
Prolonged, Sub-Maximal Events
• Examples:
• Increasing CHO intake is important to increase glycogen stores
• Should be done 36-72 hours before competition
The Pre-Event Meal
• Goals of a pre-event meal– Finish topping up glycogen
stores– Top up fluid levels– Prevent hunger
• Timing– __________ hours before
event
The Pre-Event Meal
• What to eat– __________ GI foods• Why?
– Low in __________
• Fluid– 300-400ml prior to event
During Exercise
• Events <60 mins– No intake needed, stored CHO and
fat is adequate
• Team sports 60-90 mins– CHO intake helps maintain blood
glucose levels
• Endurance events >90 mins– Very important; 500-1000ml of
sports drink per hour
• Ultra endurance events >4 hrs– Solid food high in CHO– Small amounts of fat and protein
Recovery
• Restore __________ and liver glycogen levels quickly
• High GI foods within __________ mins of activity
Dietary Strategies
• Carbohydrate loading
• Creatine supplementation
• Caffeine
• Hydration considerations
• Minerals
Carbohydrate Loading
• Benefit for athletes exercising for 90+ mins
• Increases muscle glycogen levels– Exercise at optimal pace for
longer• Exercise tapers off and
carbohydrates are increased• Prolongs CHO as main fuel
and delays reliance on fats• May increase in __________
due to extra muscle glycogen and water
Creatine Supplementation
• Hope to increase power, strength and anaerobic performances
• Powder ingested daily for 5-7 days
• Increase in rate of PC resynthesis during recovery between bouts of high intensity activity– Eg: interval sprint training– Better able to use __________
system to provide energy before using lactic acid system
Creatine Supplementation
• Possible side effects–Weight gain due to
increase in water retention–Muscle cramps,
dehydration– Seizures, diarrhoea,
anxiety
• Only to be considered after consulting a dietitian or nutrionist
Caffeine
• Benefits– Glycogen sparing for
endurance athletes– Stimulates CNS, which can
alter perception of fatigue and effort
– Stimulates release and action of adrenaline
– Diuretic (promotes fluid loss)
• Who would use it?
Caffeine
• Side effects– Diuretic: fluid loss =
dehydration and impact on temperature regulation
– Insomnia– Elevated blood pressure
• Where from?
• Doping controls?– Yes, allows normal ‘social’
consumption
Hydration Considerations
• Water alone is not the most efficient way to rehydrate– It causes bloating, reduces thirst,
increase urine output
• Fluid lost when exercising contains mineral salts (__________) that need to be replaced
• Sports drinks are used because they contain electrolytes and carbohydrates
Hydration Considerations• Hypotonic
• Low electrolytes and CHO levels• Absorbed quickly• Suitable for athletes who need fluid,
without CHO
• Isotonic• Similar amounts of electrolytes and
CHO that the body requires• Absorbed quickly• Preferred by athlete for refuelling and
rehydrating
• Hypertonic• Very concentrated with CHO• Slower absorption• Usually after exercise to replace
glycogen
Minerals
• Often minerals supplements are taken– Iron, calcium, magnesium,
potassium, sodium, zinc, phosphorus
• However, a healthy balanced diet contains enough minerals
• Eg: Iron– Increases oxygen carrying
capacity of RBC– Hence, improved __________
capacity
Activities
• Read p.117-118 and complete activity 9 (p.119)
• Go to http://www.ausport.gov.au/ais/nutrition– Read tennis fact sheet
• Complete review questions (p.355)– 3, 4, 6, 7, 8, 9, 10