NUTRITION Flashcards
What is catabolism
breaking down
what is anabolism
building up/together
opposite of breaking down
when is net muscle protein balance the greatest (most positive)
after exercise and protein ingestion
approximately what rate does protein turn over per day (%)
1-2% per day
In the post exercise period, the MPS response to protein ingestion is enhanced, how long do the effects last
24-48hrs
what does MPS stand for
muscle protein synthesis
to maximise training adaptations, what protein intake per day is recommended?
1.6-2kg per day
which amino acid is important in initiating muscle protein synthesis
Leucine
during a diet what happens to protein synthesis
its reduced
What is sports nutrition
The study and practice of nutrition and diet as it related to athletics performance.
concerned with the type and quantity of fluid and food taken in by the athlete and deals with nutrients such as vitamins, minerals, supplements and organic substances.
why do we communicate nutrition science?
- helps people know about a balanced diet
- reduce obesity therefore reduce strain on NHS
- More people can work if healthier
- food underpins cultures
- food banks/ free school dinners
- promote yourself as an expert
what is the deficit model of science communication
experts speak at society and they don’t understand
what is the dialogue model of science communication
there is communication between experts, governments, society, trade and industry
what is the gradient model of science communication
science communication links science and the public
what is the rhetoric of science
links these 3:
ethos- trusthworthyness, tone style
logos- facts, stats, case studies, scientific evidence
pathos- emotional impact, personal connection
where does science communication go wrong
innacurate bias boring overcomplicated oversimplified
what is ATP hydrolysis
the breakdown of ATP using water
ATP + h20 –> energy + ADP + H+
what is ATP resynthesis
creating ATP
ADP + Pi –> ATP
Where is ATP stored
in the muscle
what processes aid the resynthesis of ATP
Creatine phosphate system
Glycolysis
Oxidative phosphorylation
where is glycogen stored
in the liver
where are triglycerides stored
in the adipose tissue
what processes are part of substrate level phosphorylation
PCr breakdown
Glycolysis
what energy systems are working at intense exercise
PCr, glycolitic and oxidative phosphorylation
what fuels are being used at steady state exercise
other fat sources
Plamsa free fatty acids
plasma glucose
muscle glycogen
what fuel is used first carbohydrate or fats
carbohydrates are used first and then fats take over as the main energy source
what is ATP resynthesis supported by
substrate level phosphorylation and oxidative phosphorylation
what determines what fuels are used
the exercise intensity and duration
what are the functions of nutrients
- provision of energy
- regulation of metabolism
- promotion of growth development
what are macronutrients and examples
required in the diet in large amounts
Carbohydrates
Fat
Protein
Water
what are micronutrients
Vitamins
Minerals
Trace elements (zinc, iron, copper etc)
what is the gastrointestinal (GI) tract made up of
Mouth
Stomach
Small intestine
Large intestine
what is the function of carbs
energy
physical activity
central nervous system
fibre; health benefits
what are the functions of fats
- energy source
- protection of vital organs
- cell membrane consituents
- precursors of bile, hormones and steroids
- fat soluble vitamin intake
- palatability
what are the functions of proteins
- provide structure to all cells in body
- are enzymes that increase the rate of metabolic reactions
- amino acids have central roles in the metabolism of many organs and tissues
- amino acids are precursors for the synthesis of body proteins
- amino acids are precurosirs and regulators of the synthesis of neurotransmitters, hormones, DNA and RNA
what are the functions of water
- Functions; nutrient transport, protection, temperature regulation, biochemical reactions, medium for reactions
- Adult body = 60% water
- 2/3 of water found in cells
- 1/3 extracellular
what are the functions of nutrients
energy
growth
regulation of metabolism
what is a negative energy balance
when the total energy expenditure is LARGER than the energy intake
what is energy Intake
the metabolised energy content of food (kcal/g)
what is energy expenditure
energy used for resting metabolic rate, thermic effect of food, movement and exercise or physical activity
what is energy availability
energy available to support an individuals body functions
once the energy expenditure of exercise is deducted from energy intake
how do you calculate energy availability
(energy intake - exercise energy expenditure)/ fat free mass
how do you calculate FFM
look at how much of bodyweight is body fat in kg
the remainder is FFM
what energy availability is required for growth
energy availability > 45kcal/kg FFM per day
what energy availability is required for stable body mass
energy availability approximately 45kcal/kg FFM per day
what energy availability is required for weight loss
EA 30-45 kcal/kg FFM per day
what are the causes of low energy availability
- Energy intake too low
Poor dietary practices
Reduced available eating time
Eating disorders - Exercise energy expenditure too high
Endurance athletes
High training volumes/ schedules
Additional physical activity to reduce or maintain bodyweight
what does RMR stand for
resting metabolic rate
what does REDS stand for
relative energy deficiency in sport
name some consequences of REDS
- inhibited immunoglocigal functions
- inhibited menstrual function
- inhibited bone health
- inhibited endocrine & metabolic functions
- inhibited growth and development
- inhibited cardiovascular responses
- inhibited psychological responses
- inhibited gastrointestinal responses
what sports are risky in athletes with REDS
- weight catageory sports eg boxing and rowing
- aesthetic sports eg diving, gymnastics & dance
describe carbohydrate utilisation during exercise
- Exercise increases carbohydrate oxidation in an intensity dependent manner
- Increased liver (hepatic, endogenous) glucose output
- Increased muscle glucose uptake
- Increased muscle glycogen breakdown
describe fatigue during prolonged strenuous exercise
- Strongly correlated with carbohydrate depletion & Muscle glycogen depletion
- And hypoglycemia reflecting liver glycogen depletion
- Evidence diet can affect these processes
what is daily carb recommendations based on
based on body weight (not % of energy intake)
can be altered due to training and competition needs (periodisation)
what % of total daily energy intake is fats
20-35%
with saturated fats being less than 10%
what benefits does ketogenic adaption have
- elevated blood levels of ketones and tissue adaptions to enhance their use as fuel
- increase use of fat as muscle fuel
after how many weeks does ketogenic adaptation occur
after 2-3 weeks
what does a positive energy balance result in for body mass
body mass gain
what does a negative energy balance result in for body mass
body mass loss
give some examples of fast carbohydrates
glucose maltose sucrose malodextrins starches rich in amylopectin
give some examples of slow carbohydrates
fructose alone
galactose
isomaltulose
starches rich in amylose
when talking about fast and slow carbs - what does the fast and slow refer to
the speed at which they’re digested, absorbed and made available to the body for energy provision
is it beneficial to eat carbs during exercise
YES- carbohydrate feeding during exercise of about 45 mins or longer can improve endurance capacity and performance
what are the metabolic effects of carbohydrate feeding during exercise
- Maintains or elevates plasma glucose, helps to sustain carbohydrate oxidation
- Spares liver glycogen (again helping to sustain plasma glucose and carbohydrate oxidation)
- May spare muscle glycogen
What are the non-metabolic (central) roles of carbohydrate feeding during exercise
- Carbohydrate mouth rinsing appears to improve short term high intensity exercise performance
- More consistently when subjects perform in overnight fasted state
- May be related to central fatigue mechanisms linking oral carbohydrate sensing to motor output
describe multiple transportable carbohydrates
sugars that are transported across the intestine by stimulating more than 1 protein transporter
- This can increase exogenous carbohydrate oxidation by 20-50% above single transported carbohydrates and improve gut comfort
- Recommended for sustained intense exercise (2.5-3hrs +)
what mechanisms help glycogen repletion post exercise SHORT TERM
More specific strategies may help ensure rapid glycogen repletion
what happens to glycogen repletion post exercise LONG TERM
adoption of general daily CHO intake should ensure repletion on day to day basis
what are the general daily carb intake guidelines for athletes performing LIGHT exercise
3-5g/kg/d
what are the general daily carb intake guidelines for athletes performing MODERATE exercise
5-7g/kg/d
what are the general daily carb intake guidelines for athletes performing HIGH exercise
6-10g/kg/d
what are the general daily carb intake guidelines for athletes performing VERY HIGH exercise
8-12g/kg/d
where does glycogen synthesis occur
in skeletal muscle
how many phases does glycogen resynthesis have
2 phases
What are the 2 phases of glycogen resynthesis
- Insulin Independant (rapid phase)
- Insulin Dependant (slow phase)
describe the events leading to glycogen synthesis
- exercise induced GLUT-4 translocation
- Increased blood glucose conc will increase glucose uptake by mass action (if carbs consumed)
- insulin increases glucose transport (if carbs consume)
- insulin stimulates glycogen synthase
is there more or less glycogen synthesis if you consume carbs immediately after exercise or 2 hours after
More glycogen synthesis when you consume carbs IMMEDIATELY post exercise
which glycemic index is best in carbs for glycogen synthesis
carbs with a moderate to high glycemic index
when does protein co-ingestion help with glycogen synthesis
protein co ingestion can help increase muscle glycogen synthesis when carb intake is SUB-OPTIMAL <1.2g/kg/h
what is a benefit of post exercise fructose co ingestion with glucose
accelerated glycogen stores replenishment
enhance subsequent time to fatigue
what are the essential nutrients for humans
water amino acids fatty acids minerals trace minerals electrolytes vitamins ultra trace elements
give some examples of conditionally non-essential amino acids
arginine cystine glutamine glycine proline tyrosine
give some examples of essential amino acids
histidine isoleucine leucine lysine methionine phenylalanine threonine tryptophan valine
give some examples of non-essential amino acids
alanine asparagine aspartate glutamate serine
role of amino acids?
- Amino acids have central roles in the metabolism of many organs and tissues
- Amino acids are precursors for the synthesis of body proteins
- Amino acids are precursors and regulators of the synthesis of neurotransmitters, hormones, DNA and RNA.
what compound does the body get some of its nitrogen from
amino acids
what are the 3 sections to an Amino acid
amino group
carboxyl group
R- side chain
what is an amino group
NH2
what is a carboxyl group
COOH
what does the nitrogen protein balance state
what goes in must come out
goes in as protein, comes out as urine, faeces or sweat
how do you calculate the nitrogen balance
- determine nitrogen excretion (eg urine etc in grams per 24hr period)
- determine nitrogen intake (protein intake in grams per day divided by 6.25)
- subtract them
what does RNI stand for
reference nutrient intake
what are the limitations of nitrogen balance
- No information of tissues
- Lack of sensitivity
Only gross measures of intake and excretion - Zero balance on low intake may reflect accommodation (similar to low EA concept)
- Positive balance may not relate to lean body mass
what does MPS stand for
muscle protein synthesis
what does MPB stand for
muscle protein breakdown
how to work out net protein balance
MPS - MPB
What happens to MPS when you eat
upon eating MPS increases
how is the NET UPTAKE of protein calculated
the area UNDER the curve of net balance
what type of training do you need to do to increase variations in protein synthesis
with RESISTANCE EXERCISE, variations in protein synthesis are greater in the fed state
what type of proteins does resistance training help with the synthesis of
increases the synthesis of FORCE producing proteins
what type of proteins does endurance training help with the synthesis of
increases the synthesis of ENERGY producing proteins
What does EAR stand for
estimated average requirement
what does RDA stand for
recommended dietary allowance
what are EAR and RDA based on
nitrogen balance studies
what does EAA stand for
essential amino acids
what does MAA stand for
mixed amino acids
what is required to increase MPS after resistance exercise
EAAs
is milk consumption beneficial after exercise
YES
Post exercise milk consumption promotes greater MPS than Soy protein
Greater MPS after exercise means what
Greater recovery
what makes up milk protein
Whey protein (20%) Casein (80%)
is whey a fast or slow protein
FAST
is casein a fast or slow protein
SLOW
What is leucinemia
a rapid rise in EAAs after eating a meal (post-prandial)
what is post prandial
after eating a meal
why would we eat before we sleep?
So slow proteins can act over night
what factors help lean mass preservation/ gain during energy restriction
- exercise training (particularly resistance)
- High dairy protein consumption
- High protein diet
- Slow rate of weight loss
- Early post exercise protein intake
- Balanced distribution of daily protein intake
what % of adult body is water
50-70%
what % of fat mass is water
5-10% water
what % of lean body mass is water
73%
what are the functions of water
- nutrient transport
- protection
- temp regulation
- biochemical reactions
- medium for reactions
what is the approximate daily water loss in mL/d
-1300 to -3450
what is the approximate daily water production in mL/d
+250 to +350
are sweat losses >1L/h common
YES
Why do we sweat
- Sweating is the bodys principle means of preventing excessive rises in body temp during exercise (hyperthermia)
- Normal body temp = 36-38 degrees
- During exercise this increases to 38-40 degrees
- Evaporative cooling
1L of sweat evaporated will remove 573kcal of heat from the body
what is net body water balance
the difference between fluid water (intake + production) - (fluid loss)
when is net body water balance challenged
during periods of high/ increased sweating
what is ‘Ad libitum drinking’
the consumption of fluid whenever, and in whatever volume, is desired
during high sweat periods what does ad libitum drinking lead to
a body water deficit (dehydration)
describe dehydration
defined as a body water deficit greater than normal daily fluctuation
(Sometimes referred to as hypohydration)
- Change in body mass provides the most sensitive and simplest measure to determine acute changes in body water
- Acutely >2% body mass reduction = 90% chance that body water defecits are sufficient to be classed as dehydration
how does sweating effect blood plasma and blood volume
sweating decreases both blood plasma and blood volume
when sweating why does the plasma osmolality increase
the sweat is hypotonic (lower conc of fluid than blood plasma)
how does sweat loss/ hypohydration effect cardiovascular strain
sweat loss which reduces plasma volume, increases cardiovascular strain
how does the redistribution of blood effect cardiovascular strain
redistribution of blood flow to skin to aid thermoregulation, further increases cardiovascular strain
as the environmental temp increases what happens to skin temp
skin temp also increases
if an athlete is dehydrated - what is the threshold temp value after which performance decreases
27 degrees
every 1 degree warmer performance reduces by 1.5%
why do we need to drink during exercise
to counter sweat losses that occur to assist thermoregulation
how do you statically measure hydration index
through measuring plasma osmolality
a measure of the total dissolved particle conc
typically 275-295mOsm/kg
how do you dynamically measure hydration index
- track body mass change (in energy balance)
- plasma osmoality
- urine specific gravity
what does RCV stand for
reference change value
what are drinking guidelines 2-4hrs pre exercise
5-10ml fluid per kg body weight
(sodium, salt snacks or small meals may help)
more fluid if dark urine
what are drinking guidelines during exercise
sufficient fluid to limit body mass losses to <2%
what are drinking guidelines post exercise
rapid recovery before 12 hours
consume 1.25-1.5L for each kg of body mass lost + sodium
why drink sodium pre exercise
fluid retention
why drink sodium during exercise
limit electrolyte losses (risk of hyponatremia)
Stimulate thirst
why drink sodium post exercise
restoration of sodium and fluid balance
what is hyponatremia
sodium level in blood is below normal
what is a dietary supplement
A product taken by mouth that contains a ‘dietary ingredient’ intended to supplement the diet
what are some reasons for using supplements
- Aid recovery
- For health
- Improve performance
- Prevent/ treat illness
- Compensate for poor diet
- Financial gain (sponsorship)
- Believe that other athletes are using them
What are the costs of supplementation
financial
health
performance
drug test failure
What are the benefits of supplementation
performance
health
free samples
what is WADA
World antidoping agency
Why were doping rules created
to promote fairness in sport and to protect the health of the athlete
What are the risks of supplement use
- Contamination
- Absence or lower than declared levels of “actives” (supplements may not contain the actual amount of the ingredient stated)
- presence of undeclared doping agents (links to 1)
- Harmful to health/ performance
describe contamination
Supplements may contain undeclared prohibited substances
for example, due to poor manufacturing practices resulting in contamination of the raw ingredient or deliberate inclusion of ingredients not listed on the label (or labelled under a different name)
Whats a website/ company where you can get approval on your supplements
informed sport
what vitamin supplement would be appropriate for vegans/ veggies
Vitamin B12
Timing wise why would athletes sometimes supplement
if an athlete cannot consume their everyday or normal diet due to training schedules etc they may need to supplement so that they can still get their nutritional needs
what are some examples of evidence based ergogenic aids
caffeine creatine nitrate beta-alanine sodium bicarbonate
what is the catchphrase about food
food first, but not always food only
what is caffeine (structure)
1,3,7- trimethylxanthine
where is caffeine metabolised
in the liver
when does peak blood caffeine occur in relation to exercise
60 min after ingestion
what is the half life of caffeine
5 hours
can caffeine cross the blood brain barrier
YES
what are the effects of caffeine
- improved vigilance and alertness
- reduced perception of effort
- reduced fatigue and pain
- IMPROVED PERFORMANCE
how does caffeine work (3 ways)
- When adenosine binds to its receptor, this causes fatigue. Caffeine prevents adenosine binding and therefore delays fatigue
- Caffeine stimulates lipolysis (breakdown of triglycerides) both directly and indirectly via an increase in adrenaline/ epinephrine. This may spare muscle glycogen but not likely.
- Caffeine stimulates calcium release which is important for muscle contraction
what dose of caffeine is needed to increase CHO absorption
High doses of caffeine
however this is NOT recommended, due to increased side effects
can caffeine improve a variety of sports??
Yes, endurance, power, high intensity
give some examples of caffeine containing things
LOW TO HIGH
Decaf coffee Coke/ pepsi Red Bull Cappuccino Double expresso Latte Energy shot Energy drink
What is an advantage of using caffeinated gum
The majority of caffeine bypasses the gut
Increased absorption, decreased gut distress
Do both caffeine as a supplement and in coffee improve performance
YES
What is the optimal dose of caffeine for enhancing athletic performance
~3mg/kg per body mass
What do large amounts of caffeine do
Cause bad side effects
Is it good to take caffeine during the event
Can take lower doses throughout
~1.5mg/Kg
what is co ingestion of caffeine
caffeine taken with CHO
how can caffeine be consumed
coffee capsules gum gels sports drinks
does caffeine habitual consumption have ergogenic effects??
NO
does caffeine co-ingestion with CHO have ergogenic effects??
YES
What is also good about caffeinated drinks
They also contribute to hydration
Give some reasons caffeine can have different effects on individuals
Genetics Age Training status Diet Smoking Menstrual cycle
what are the risks of caffeine consumption
SLEEP
- Can affect sleep onset and quality, interfering with athletes recovery
HYDRATION
- Small to moderate doses of caffeine have minimal effects on urine losses or overall hydration
Caffeine containing drinks contribute to fluid intake
what are some side effects of of caffeine
anxiety jitters insomnia inability to focus Gut unrest Irritability
Withdrawls (addictive)
is caffeine in WADAS prohibited list
NO
what is creatine synthesised from
from Amino Acids (arginine, glycine and methionine)
where is creatine synthesised
liver
pancreas
kidneys
where is the majority of creatine stored
skeletal muscles
>95%
what are the 2 ways creatine can be stored
phosphocreatine
free creatine
what happens to PCR when exercising at max
pCR increases but then rapidly depleted (within 10s)
how long does it take for pCR resynthesis
4 min
how much creatine is synthesised a day
2g per day
how much creatine is excreted a day
2g per day
what are the effects of taking creatine
- Increased PCr synthesis
- Increased Cr in muscle
- Ability to perform short term high intensity repeated bouts of exercise
- Decreased muscle damage
- Increased muscle glycogen
what are some examples of natural creatine
meat and fish
what is an example of natural supplementary creatine
CM (creatine monohydrate)
- white poweder
- consume with carb containing liquid or food
does creatine have an acute effect
NO
what is the washout period for creatine
4-6 weeks
should creatine be co-ingested
YES
co-ingestion with a mixed meal results in enhanced muscle creatine uptake
what type of exercise does creatine have the largest effect on
<30s tasks
-repeated high intensity exercise and chronic resistance and interval training leading to greater gains in lean mass and muscular strength/ power
is there individual variability in regards to creatine
BASELINE CREATINE LEVELS
Individuals that have high muscle creatine levels will experience low creatine uptake from supplements
Individuals that have low muscle creatine levels will experience high creatine uptake from supplements
does creatine supplementation depend on sport type
In sports where performance is not determined by PCr availability, creatine supplementation will likely not have any effects (eg ultra endurance events/ skill based events)
what does creatine do to body mass
increases body mass by 1-2kg
what are some myths about creatine
that creatine can cause kidney damage, muscle cramps, strains, damage/ injury, affects fluid balance
what is a potential side effect of creatine
gut upset
describe the ways of Creatine monohydrate loading
SHORT
(20g per day for 5 days)
LONG
(3-5g per day for 20-30 days)
is creatine supplementation safe
generally yes
just watch for contamination (like other supplements)
what types of food contain high nitrate
leafy green vegetables root vegetables (BEETROOT)
what does the ingestion of nitrates lead to
-enhanced NO bioavailability (nitric oxide) -Increased blood flow to muscles -Increased function of type2 fibres -Increased efficiency of mitochondrial respiration -Increased contractile function
what does NO (nitric oxide) do
modulates skeletal muscle function
what are the 2 ways to supplement with nitrates
ACUTE
(2-3hrs pre exercise)
CHRONIC
(3-15 days pre event)
what not to consume with beetroot juice
mouthwash or chewing gum
When would nitrate supplementation be useful
- Prolonged submaximal exercise (endurance events)
- Training aerobic fitness
- HIIE events with short duration and sprint efforts
what fibres does nitric oxide effect
type 2 fibres
what individual variability is seen with nitrate supplementation
Gender
Training status of athlete (Elite athletes need larger amounts of nitrate to see effect)
what are the concerns with nitrate supplementation
- Beetroot juice (especially concentrated) can cause mild gut discomfort
- Beetroot juice can also cause pink wee
- Long term effects are unknown
what does nitrate do to exercise capacity
Increase exercise capacity by reducing the oxygen cost of exercise (increased exercise economy)
what is carnosine
DIPEPTIDE
an intracellular pH buffer
what is beta alanine
a beta amino acid precursor of carnosine
what is carnosine made up of
2 amino acids
beta alanine & histidine
where is carnosine found in body
human skeletal muscle
what food can you get carnosine from
red meat
chicken
fish
seafood
what is the rate limiting factor to carnosine synthesis
beta alanine
what are the effects of carnosine
- decreased muscle acidosis
- decreased fatigue
- increased exercise capacity
what performance benefits does carnosine have
small benefits during both continuous and HIIE (30s-10min)
specifically how does beta alanine supplementation work
- CHRONIC beta alanine supplementation increases muscle carnosine levels
- Higher levels of muscle carnosine enhance intracellular buffering of H+ ions produced during anaerobic glycolysis
- Greater muscle buffering capacity can limit/ delay fatigue and improve exercise performance when exercise is limited by acidosis
how often is beta alanine supplementation required
multiple times a day for at least 4 weeks to achieve meaningful increases in muscle carnosine levels
how can you take beta alanine
available in powder or tablet / capsule form
slow release capsules help improve retention
what is the washout period of beta alanine
2 weeks
how can you load with beta alanine
- 2g per day for 8-12 weeks
6. 4g per dat for 4-8 weeks
when would beta alanine supplementation be beneficial
short sustained high intensity sports (30s-10min)
eg rowing, track cycling, swimming, middle distance running
when training intensity is prioritied/ pre comp
what ar the individual variations with beta alanine
Baseline carnosine levels (athletes with plant based diet may have lower levels of carnosine, therefore further room for improvement)
Training status (trained athletes = better at buffering
what are side effects of beta alanine supplementation
Paraesthesia
(tingling sensation like pins and needles on skin can last up to an hour)
skin rashes
what is sodium bicarbonate
an extracellular blood buffer which maintains pH
what are the effects of sodium bicarbonate
- decreased blood and muscle acidosis
- decreased fatigue
- increased metabolic function
- increase exercise capacity
how does sodium bicarbonate specifically work
- Ingestion of sodium bicarbonate increases extracellular pH
- This increases the H+ gradient between intracellular and extracellular environments
- Enhanced activity of H+ and lactate ions as co-trasnporters
- H+ and lactate moved away from active muscles
- They are then buffered or taken up into adjacent or inactive muscle fibres
how do you supplement with sodium bicarbonate
ACUTE
2-2.5hrs before exercise
200-400mg per kg body mass
consume slowly over 30-60min
what are the primary side effects of sodium bicarbonate supplements
gut upset weight gain nausea stomach pain diorrehea vomiting
when would supplementing with sodium bicarbonate be useful
longer duration events
eg 1-7min run, rowing, racket sports
enhance training capacity
what is ketogenic adaptation
the process your body goes through on the diet as it changes from using primarily glucose for energy to using primarily fat.
What is an acute effect
taking it once and it working = acute effect
if you have to take it for 4-6 weeks it does not have an acute effect
what is energy balance
the amount of dietary energy added to or lost from the body’s energy stores after the body’s physiological systems have done all their work for the day.
what are the 3 parts to energy expenditure
Resting or basal metabolic rate
Thermic effect of food or diet-induced thermogenesis
Physical activity
what would be regarded as low energy availability
Less than 30 kcal/kg FFM/d
If you were going to recommend one of the milk protein fractions over the other for stimulating muscle protein synthesis in the immediate post-exercise period, which fraction would it be and why?
Whey (1).
Whey is digested and absorbed more rapidly (1)
Casein forms a clot in stomach and is slowly digested absorbed (1)
Whey has a higher leucine content, particularly important for muscle protein synthesis (1)
How would the carbohydrate feeding guidelines differ for someone involved in 1 hour of intense endurance exercise, as compared to someone performing endurance exercise lasting 2 hours?
60 min, recommendation is small amounts of carbohydrate (1) or mouth rinse
(1)
2 hours, recommendation is 30-60 g per hour (1) of rapidly oxidiseable
carbohydrates (1)
What are the possible mechanisms by which carbohydrate feeding during exercise enhances performance during prolonged endurance exercise?
Maintains blood glucose levels
Maintains carbohydrate oxidation
Spares liver glycogen (or suppresses endogenous glucose production
May spare muscle glycogen
What risks might there be if the athlete tried to obtain the amount of caffeine you specified from consuming coffee from coffee shops?
There is considerable variability within and between retail outlets in terms of caffeine content in coffee so there is a risk of insufficient caffeine to be effective or excessive caffeine that might induce side effects
In the absence of feeding carbohydrate during exercise, which factors related to fuel availability are likely to contribute to fatigue during prolonged strenuous endurance exercise?
- Muscle glycogen depletion (1 point)
- And/or hypoglycaemia (1 point) reflecting liver glycogen depletion (1 point)
Provide two reasons why protein requirements beyond the current RNI/RDA might be optimal for muscle and whole-body health in athletic populations.
Repair replace and remodel damaged proteins (e.g. muscle),
optimize function of metabolic pathways using AA’s
support lean tissue remodelling,
support optimal function of the immune system.
what is ergogenic
reducing the fatigue symptoms
