9 - Sports nutrition Flashcards
How much ATP can be produced per mol of:
Glycogen (anaerobic glycolysis)
Glycogen (aerobic glycolysis)
Fat (Aerobic beta oxidation)
Glycogen (anaerobic glycolysis) = 3 ATP
Glycogen (aerobic glycolysis) = 39 ATP
Fat (Aerobic beta oxidation) = 129 ATP
Which is faster, aerobic or anaerobic glycolysis of glycogen?
Anaerobic but it yields less ATP
Muscle fatigue while running a marathon is most likely due to a lack of…?
Muscle glycogen
What happens to Pyruvic acid in:
a) Anaerobic glycolysis
b) Aerobic glycolysis
Anaerobic: Pyruvic -> Lactic acid
Aerobic: Pyruvic -> KREBS/ETS cycle
What is the harris benedict formula?
Measures your energy needs (BMR + energy expenditure)
What are the types of carbohydrates?
Monosaccharides - eg glucose, fructose, galactose
Disaccharides e.g. sucrose, lactose, maltose
Polysaccharides e.g. starch, glycogen, cellulose
Fibre e.g. resistant starches
What % energy needs come from carbohydrates?
58%
or 60% at 75% VO2 max
How do athletes taper for an event (in terms of carb requirements)
a) 3-4 days prior to event
b) Day before
c) On the day
d) After the event
*3-4 days prior: lower muscle glycogen and train with moderate carbohydrate input
*Day before: Carb load - consume 10g/kg
*On the day: Meal 90 mins to 4hrs before - low in fat and fibre and high in carbs. Moderate in protein.
+ Consume Maltodextrin and glucose every 20 mins
*After: 1.5g per kg carb
What are the physiological events in the postprandial period?
a) 0-2 hours
b) 2-4 hours
c) 4-6 hours
a) 0-2 hours: hyperglycaemia, hyperinsulinemia, hypoglucagonemia
b) 2-4 hours: Reactive hypoglycaemia, decreased free fatty acid oxidation, increased appetite
c) 4-6 hours: Counter reg hormone response to euglycaemic and FFA conc
Protein / Amino acid:
a) % energy needs =
b) Daily requirement/kg =
c) Endurance athlete req/kg =
d) Resistance athlete req/kg =
a) % energy needs = 2%-15%
b) Daily requirement/kg = 0.8g
c) Endurance athlete req/kg = 1.2-1.4g
d) Resistance athlete req/kg =1.2 - 1.7g
What are the energy needs per day for fat?
25-30%
or 66% at 50% VO2 max
What are the electrolytes?
Where are they found?
What is their biochemical function?
Sodium and chloride, potassium, phosphorus
Found in water-based body fluid
Na+, K+ extracellular nerve conduction
Cl- and HPO42- intracellular. Maintain osmosis.
How much sodium, chloride, potassium and phosphorus do we need per day?
1.5g sodium, 2.3g chloride, 4.7g potassium, 0.7g phosphorus
1g salt = __g sodium?
1.g sodium = __g salt?
1g salt = 0.4 g sodium
1.g sodium = 2.5 g salt
What are nutraceuticals?
What are Ergogenic acids?
Nutrition or pharmaceuticals that provide benefits
Ergogenics = specific compounds of foods that enhance performance. They affect energy metabolism, the CNS, and muscle mass.
Give some ergogenic acids that actually work?
Protein, creatine, sodium bicarbonate, caffeine, beta-alanine, carnosine.
What is the role of CP in muscle fatigue?
Increases intramuscular buffering capacity -> delays fall in PH -> delays fatigue
What is the step-by-step creation of creatine from Arginine and glycine->muscle fibre
Arginine + Gycine -> Kidney -> Guanidino acetate -> liver -> creatine phosphorylcreatine (in muscle fibre)
What is the main role of Creatine?
Where is is synthesized and where is it then found?
Effects energy metabolism and maintains ATP levels
Synthesized in kidney, liver and pancreas
Found in skeletal muscle and excitable tissues
What is the recommended dose of creatine for sport performance?
20g per day for 4-5 days (loading)
then 1-2g per day (maintenance)
What is the role of Bicarbonate / Citrate in anaerobic processes?
Acts as a buffer for acidosis, lowering PH, inhibiting muscle contraction and fatigue.
How does caffeine improve performance? (3)
1) Lowers the perception of effort and fatigue, increases alertness.
2) Stimulates fatty acid mobilization from adipose tissue, increasing supply of fat for muscle, sparing limited glycogen and therefore extending performance time.
3) Affects electrolytes within muscle and promotes cycling of AMP
What is the ergogenic caffeine dose?
What is the legal limit?
3-6mg per kg 20-60 mins before exercise
Legal limit is up to 12mg.L urine (500mg in total)
Dependent on individual sensitivity.
Caffeine studies show no effect in ____ exercise
but around 20% in _____ exercise
Caffeine studies show no effect in aerobic exercise but around 20% in high intensity exercise
Explain how you would carry out a loughborough intermittent shuttle test to find the effect of caffeine vs placebo
Warm up followed by 5 blocks of 15 minutes sprinting, with 3 mins rest between each block. Total exercise time 75 mins total time 90 mins
Then fatigue test
Beta alanine:
_____ amino acid.
Binds with _____ to make _____, which prevents __ build up in muscle, delaying fatigue.
Beta alanine:
Essential amino acid.
Binds with L-histidine to make carnosine, which prevents H+ build up in muscle, delaying fatigue.
Why not take carnosine instead of beta alanine? (3)
Beta alanine is also a transmitter, acting like caffeine
Limits max carnosine produced - therefore safer
Greater capacity for storage
What food is beta alanine found in?
What is the recommended supplementation for athletes?
What intensity is beta alanine most useful for?
What is the side effect?
Food - Beef/pork (vegetarians have low levels)
Supp - 800mg 4-5X daily over 10 weeks
Intensity - high + short, e.g. football, wrestling, boxing
Side effect - paresthesia (pins and needles) above 10mg.kg body weight
What are the 3 forms of sports drink?
What do they claim to replace in the body?
Hypotonic, hypertonic, isotonic
replace salt, sugar, electrolytes and fluid
What does a good quality sports drink contain, that bad quality does not?
Citric acid, stabilisers, ascorbic acid, vitamins.
