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