Challenging decks Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the typical blood glucose, liver glycogen and muscle glycogen values (grams) of a 70kg man?

A

Blood glucose: 3-5g / 4-6g
Liver glycogen: 80-100g / 80-110g
Muscle glycogen: 300-400g / 300-600g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the typical adipose tissue and muscle triglyceride values for a 70kg man?

A

Adipose tissue: 3.5-14kg
Muscle triglyceride: 200-500g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 physiological and biomechanical functions of nutrients in the body?

A

1) Provision of energy
2) Regulation of metabolism
3) Promotion of growth and development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

3 types of carb-rich foods

A

1) Sugars: fruit juices, fruits, sports drinks, sweets, honey, sweetended cereals
2) Starches: cereal, potatoes, rice, bread
3) Fibre: whole-grain cereals and bread, oats, fruits and vegetables

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Roles of fats

A
  • Energy source
  • Protection of vital organs
  • Cell membrane constituents
  • Precursors of bile, hormones, and steroids
  • Essential fatty acids and fat-soluble vitamin intake (vitamins most abundant in fat foods such as vitamin A, D, E, K)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Protein (amino acids) roles

A
  • Provide structure to all cells in the human body
  • Central roles in the metabolism of many organs and tissues
  • Precursors for the synthesis of body proteins
  • Regulators of the synthesis of neurotransmitters, hormones, DNA and RNA
  • Enzymes that increase the rate of metabolic reactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Functions of water

A
  • Nutrient transport
  • Protection
  • Temperature regulation
  • Biochemical reactions + medium for reactions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the two ways that exercise increases CHO oxidation as intensity increases?

A

1) Increased liver glycogen breakdown (liver glucose output equal to muscle glucose uptake)

2) Increased muscle glycogen breakdown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does carbohydrate loading and carb intake during exercise affect fatigue?

A

Carb loading increases muscle glycogen and carb intake during exercise maintains blood glucose –> more able to match demands of ATP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can explain fatigue during prolonged strenuous exercise?

A

Fatigue strongly correlated with CHO depletion.
- Muscle glycogen depletion
- Hypoglycaemia (low blood glucose) reflecting liver glycogen depletion

This means we cannot produce ATP at an adequate rate to meet ATP demand.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the adaptations of high fat diet (fat adaptation)? Is this diet beneficial?

A
  • Increased fat oxidation
  • Decreased carbohydrate oxidation
  • Spared muscle glycogen

Evidence suggests that fat adaptation impairs high-intensity exercise performance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the adaptations of a ketogenic diet (Keto-adaptation). What is the logic/benefit of this type of diet?

A
  • Takes at least 2-3 weeks.
  • We get elevated blood levels of ketones (known as ketosis) and tissue adaptations to enhance their use as fuel.
  • This increase use of fat as muscle fuels.

Fatigue is due to reduced CHO availability and inability to use alternative lipid sources. Keto-adaptation ensures stable fuel source for exercising muscle (and brain) in the face of low CHO availability.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the “Periodised approach” to carb intake refer to?

A

refers to daily carb intake being flexible to the demands of training and competition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why would a low-fat, low fibre nutritional strategy be recommended for a pre-exercise meal?

A

to reduce the risk of gastro-intestinal (GI) problems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why should athletes try to avoid restricting fat intake below 20% of total energy intake for sustained periods of time?

A

It may reduce fat soluble vitamin and essential fatty acid uptake.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give examples of slow and fast carbohydrates.

A

Fast carbs
- Glucose
- Maltose
- Sucrose
- Maltodextrins
- Starches rich in amylopectin

Slow carbs
- Fructose
- Galactose
- Isomaltulose
- Starches rich in amylose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the effect of carbohydrate feeding during exercise on performance?

A
  • Improve endurance capacity and performance
  • Effects of carb feeding during exercise increase with exercise duration
  • May also benefit other aspects of sport performance such as motor skills during prolonged sports events (pen)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the metabolic effects (benefits) of carb feeding during exercise?

A
  • Maintains plasma glucose concentration and helps to sustain high rates of carbohydrate oxidation
  • Spares liver glycogen stores which can be used during later stages of exercise
  • May spare muscle glycogen in certain situations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is using multiple transporters carbohydrates beneficial for prolonged exercise?

A

It increases rates of exogenous carbohydrate oxidation by 20-50% above single transported carbohydrates.
It does this by reducing competition for SGLT1 transport (glucose) in the intestines due to stimulating other protein transporters (GLUT5 for fructose).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are multiple transportable carbohydrates?

A

Refer to sugars that are transported across the intestine and into the blood by stimulating more than one protein transporter (e.g. glucose {via SGLT1} and fructose {via GLUT5}).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Difference between short-term and long-term post-exercise recovery.

A

Short-term recovery is from 0-8 hours after exercise has stopped to the next session/bout. Involves strategies to ensure rapid glycogen repletion.

Long-term recovery is from 8-24hours after exercise. Adoption of general daily CHO intake should ensure repletion on a day-to-day basis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does carb intake immediately post-exercise compare with carb intake 2hours post-exercise?

A

When we consume carbs immediately post-exercise we have very high rates of glycogen synthesis. If we consume carbs 2hours post-exercise, glycogen synthesis rates aren’t so high.

Essential for short recovery window (0-4hrs from one exercise to another)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why do we get high rates of glycogen synthesis 1-2hrs after exercise?

A

some GLUT4 remains on the cell membrane which increases uptake of glucose into the cell and as exercise has finished we no longer get calcium release, AMPK, free adenosine… therefore glycogen synthesis is favoured over glycolysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the 2 phases of glycogen re-synthesis?

A

Insulin independent (rapid phase)
- 1-2hours post-exercise
- Glut4 remains on cell membrane so glucose used for glycogen resynthesis

Insulin dependent (slow phase)
- 3-4hours post-exercise
- Feeding results in pancreas releasing insulin into bloodstream which enhanced glut4 translocation and glycogen synthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Describe the regulation of muscle glycogen synthesis during exercise and post-exercise.

A

During exercise, glycogen synthesis is inhibited by Ca2+, vasodilator agents NO, free adenosine and AMPK. These factors enhance glycolysis.

When exercise finished, these chemical signals are no longer produced therefore glycogen synthase is no longer inhibited. Furthermore, glut4 remains on the cell membrane so entering glucose is used for glycogen synthesis. Additionally, when we consume food, insulin is released, and this positively regulates glycogen synthase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does the addition of protein to post-exercise carbohydrate intake increase muscle glycogen resynthesis?

A

the extra protein stimulates insulin secretion when carbohydrate intake is sub-optimal –> greater uptake of glucose that can be used for muscle glycogen resynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How may fructose-glucose ingestion post-exercise be beneficial?

A

When fructose is co-ingested alongside glucose-based carbs it accelerates the replenishment of glycogen stores (mainly liver glycogen stores).

Fructose co-ingested with glucose in recovery from exercise can also enhance subsequent time-to-fatigue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the % of water in…
a) the adult body
b) lean body tissue
c) fat mass

A

a) 50-60%
b) 75%
c) 5-10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where is most of the total body water stored?

A

Intracellular fluid (62.5% of total body water) and extracellular fluid (37.5% of total body water - interstitial fluid and blood plasma)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Define dehydration (hypohydration) and how this can be indicated.

A

Dehydration is defined as a body water deficit greater than normal daily fluctuation. This can be indicated by a body mass loss >2%.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the best static physiological index of hydration status?

A

the measurement of plasma osmolality (a measure of the total dissolved particle concentration)
- Typically 275-395 mOsm/kg
- Increase in this suggests dehydration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Examples of dynamic assessments of hydration status before and after an exercise bout.

A
  • Body mass change (in energy balance)
  • Plasma osmolality (>5mmol/kg)
  • Urine specific gravity (urine density relative to water (1.00), euhydrated at 1.003-1.035U)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How is the sweating response initiated during exercise in hot temperatures?

A

For every L of oxygen consumed 4kcal of heat is produced and most of this heat is passed to the body core.

Thermoreceptors senses increased in body and skin temperature (from 36-38 to 38-40 degrees C) and sends this to the hypothalamus.

This responds by increasing blood flow to the skin (vasodilation) and initiates sweating response. This cools body temperature and prevents hyperthermia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is evaporative cooling? For every 1L of sweat evaporated, how many kcal of heat is removed from the body?

A

Evaporative cooling is where we remove heat from the body via sweat evaporation.

573kcal of heat from the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How does sweat influence plasma osmolality?

A

it increases plasma osmolality - This is because sweat is hypotonic compared to plasma. When you sweat you lose more water but concentrations of sodium, glucose… remain high which increases plasma osmolality.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How may hypohydration impair performance when we have a BM loss of >2%?

A

1-2%: Minimal impact

2-3%
- Degrade aerobic performance
- Deterioration of sport-specific skills
- Minimal cognitive function impact (without heat stress) and reduced cognitive function (with heat stress)

> 3%: Impaired cognitive function

3-4%: Minimal impact on muscle strength and power.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the threshold for the temperature that inhibits performance?

A

29-degree threshold, after which every 1 degree warmer, performance reduced by further 1.6%.

38
Q

What is the main mechanism by which hypohydration affects aerobic performance in warm/hot conditions? What other mechanisms are there?

A

Cardiovascular strain
- High skin blood flow
- Reduced blood volume
- Reduced oxygen delivery
- Reduced metabolite removal

CNS: brain metabolism and brain temp.
Peripheral muscle factors: temperature, metabolic and afferent feedback.
Psychological: thermal comfort, perceived exertion.

39
Q

Why is sodium beneficial…
a) pre-exercise
b) during exercise
c) post-exercise

A

a) Fluid retention
b) Limit electrolyte losses (risk of hyponatremia) and stimulate thirst
c) restoration of sodium and fluid balance

40
Q

Why may adding sodium to a drink help with fluid retention?

A

it helps to maintain osmolality and reabsorption of water from kidney

41
Q

How do you calculate sweat rate (liters per hour)?

A

Weight loss + volume consumed - urine loss / duration of exercise (hrs)

Weight loss = weight before - weight after
Volume consumed = bottle weight before - after

42
Q

Hyponatremia
- What is it?
- What can it arise from?
- Who are at a greater risk?

A
  • Low blood sodium - < 135mmol/L
  • Can arise from over drinking fluids more than fluid losses (exacerbated with high sweat
    sodium losses + low sodium
    beverages)
  • Recreational athletes and women at greater risk.
43
Q

Essential proteins

A

those that the body cannot synthesize endogenously and must be consumed through dietary sources (exogenous)

44
Q

What does whole-body protein balance inform us?

A

whether an individual is consuming sufficient dietary protein levels required to support human health

45
Q

What are the 3 ways we can measure protein leaving the body?

A
  1. Feaces
  2. Urine (majority)
  3. Sweat, skin, hair losses
46
Q

What factors contribute to overall protein balance (in)?

A

1) Protein consumed
2) Protein secreted across different components of the GI system

47
Q

What happens to excess amino acids in the liver?

A

they are released into the bloodstream and used in peripheral tissues such as skeletal muscle.

48
Q

Amino acids are a source of …. in the body. What % of protein is made up of…?

A

Nitrogen
16% of protein is nitrogen

49
Q

How to calculate nitrogen (protein) balance?

A

1) Determine nitrogen excretion (e.g. urine, feces, sweat) in grams per 24h period.
2) Determine nitrogen intake: protein intake (grams per day) divided by 6.25
3) N balance = Intake minus excretion

50
Q

What can calculating nitrogen balance estimate?

A

the protein intake required to maintain protein balance

51
Q

Limitations of nitrogen balance method.

A
  • No information of tissues (only whole body)
  • Lacks sensitivity (only gross measures of intake and excretion)
  • Zero balance on low intake may reflect accommodation
  • Positive balance may not relate to lean body mass
52
Q

What is the major determinant of muscle mass regulation?

A

Muscle protein synthesis
- Protein synthesis rates fluctuate a lot more whereas protein breakdown is more robust.

53
Q

How does exercise/training influence protein synthesis variation in a fed state and a fasted state?

A

With exercise, variations in protein synthesis are greater in the fed state and decline less in the fasted state.
Therefore, muscle protein synthesis > muscle protein breakdown and we are in a positive net protein balance.

54
Q

Why is the protein synthesis response to the first meal after exercise increased?

A

the muscle is more responsive to the muscle anabolic properties of protein nutrition in the early phase of post-exercise recovery (muscle anabolic window) - its better able to make us of the amino acids derived from protein ingestion

55
Q

Order the following in terms of the % of muscle protein they contain:
- Muscle Collagen
- Sarcoplasmic
- Myofibrillar
- Mitochondrial

A

Myofibrillar - 50-60%
Sarcoplasmic - 30%
Muscle collagen - 15%
Mitochondrial - 5-10%

56
Q

Order the following in terms of the protein synthesis rates:
- Muscle Collagen
- Sarcoplasmic
- Myofibrillar
- Mitochondrial

A

mitochondrial
sarcoplasmic
muscle collagen
myofibrillar

57
Q

How does myofibrillar and mitochondrial protein synthesis rates respond to:
a) endurance exercise
b) resistance exercise

A

a) Endurance exercise increases the synthesis of energy producing proteins (mitochondria)
b) Resistance exercise increases the synthesis of force producing proteins (myofibrillar)

58
Q

Benefits of taking dietary protein above the RDA of 0.8g/kg/day (recommended dietary allowance)

A
  1. Repair replace and remodel
    damaged proteins (e.g. muscle)
  2. Optimal function of
    metabolic pathways using AA’s
  3. Support lean tissue
    maintenance and/or accretion
  4. Support optimal function of
    the immune system
59
Q

Important amino acids in initiating muscle protein synthesis

A

Leucine, Glutamine, Valine, Isoleucine, Lysine

60
Q

What is in milk that makes it more effective than soy protein?

A

Milk protein is 20% whey protein and 80% casein protein - whey protein and casein have higher amounts of essential amino acids such as leucine compared to soy protein.

61
Q

How does whey protein and casein protein differ?

A
  1. Contain two different proportions of essential amino acids: whey protein has a greater amount of total essential amino acids (leucine) compared to casein.
  2. Different digestion and absorption kinetics: whey protein is fast-acting (its absorbed quickly) whereas casein is slow-acting.
62
Q

Is leucine greater in soy protein, whey protein or casein?

A

Whey protein (12.2) compared to casein (8.9) and soy (8.2)

63
Q

Muscle protein synthesis rates are greatest in rested and exercises muscle with what type of protein ingestion? Explain this.

A

Whey protein ingestion - greater total essential amino acids (49.2) such as leucine + rapid digestion and absorption properties (rapid appearance in circulation)

64
Q

What are potential techniques to make plant-based proteins more effective, in terms of their anabolic properties?

A
  1. Consuming more to meet essential amino acids requirements.
  2. Blend plant-based proteins together to make up for specific amino acid deficiencies (Soy-corn blend).
65
Q

Total EAAs in whey protein, casein protein and soy protein.

A

Whey is 49.2
Casein 40.7
Soy is 36.

66
Q

Evidence suggests that slowly digested proteins, such as casein, can be used to support muscle anabolism and growth in the overnight period. Outline the evidence from acute and chronic studies to support this notion.

A

Acute pre-sleep casein protein intake augments overnight MPS rates and net protein balance is positive.
Chronic pre-sleep casein protein intake during resistance exercise training augments muscle growth, specifically the change in type II fibre CASA is greater.

67
Q

What are the 4 risks of supplement use?

A
  1. Contamination: poor quality control in manufacturing and storage may result in undeclared prohibited substances
  2. Absence or lower than declared levels of substance/supplement (“actives”)
  3. Presence of undeclared doping agents (steroids)
  4. Harmful to health/performance
68
Q

What is the average total creatine pool in muscles?
What about the upper limit of creatine storage?
What is the average IM creatine stored in vegetarians?

A

120 mmol/kg dry muscle mass
160mmol/kg dry muscle mass
90-110mmol/kg dry muscle mass

69
Q

What is the main effect of creatine supplementation?

A

Increases PCr resynthesis
- This increases short-term, high-intensity exercise capacity to perform repeated bouts of high-intensity effort.

70
Q

Describe the mechanism of action of creatine supplementation.

A

Its important in Phosphocreatine resynthesis. It increases levels of creatine in the muscle which means we can take a phosphate from ATP to add to creatine making phosphocreatine (via creatine kinase).

71
Q

How long does it take for 80% re-synthesis of PCr?

A

4 minutes

72
Q

What are the benefits of creatine supplementation?

A
  • Increased Cr stores 30% = Increased PCr resynthesis
  • Increased muscle glycogen
  • Increase growth factor expression
  • Decreased muscle damage
  • Training harder and longer = increase lean mass/strength
73
Q

What are the best creatine sources?

A
  • Diet - red meat (beef/pork) and fish (tuna, salmon, cod, herring)
  • Creatine monohydrate (CM): white powder, 99% absorbed, better uptake mixed with a carb containing liquid or food, synthetic (suitable for vegetarians and vegans)
74
Q

When is creatine supplementation most effective? Explain why.

A

When its co-ingested with carbohydrates or carbs + protein.

When you combine creatine supplementation with carbs, carbohydrates produce an insulin response which means creatine uptake into the muscle is more effective leading to greater phosphocreatine and creatine.

75
Q

Using examples, when should we consider the use of creatine supplementation?

A

 Single (+1-5%) and repeated bouts (+5-15%) of high-intensity exercise.
 High-intensity max efforts <150 sec, largest effects on
<30 sec tasks.

Examples include;
- Power and strength sports: 100m, weightlifting
- Intermittent sports: hockey, football
- Resistance training aimed to incr. lean mass and muscular strength.

76
Q

How can creatine supplementation reduce concussions?

A

Improvements in cognitive processing in the brain and potentially reduced damage and enhance recovery from mild traumatic brain injury/concussion.

77
Q

What are individual variability considerations in creatine supplementation?

A

Baseline levels of muscle creatine
- Individuals with high muscle creatine levels will experience low creatine uptake from supplements.
- Individuals with low muscle creatine levels have the greatest potential for increases in response to supplementation.

Sport type
- In sports where performance isn’t determined by PCr availability (or fast ATP resynthesis) creatine supplementation will likely not have any effects (e.g. ultra-endurance or exclusively skill-based).

78
Q

Are there any safety concerns with taking creatine? How can this be attenuated?

A

Mild, temporary gut upset can occur but can be attenuated with split dose, longer loading protocol and avoidance of high fibre foods with ingestion.

79
Q

Where is creatine synthesized?

A

endogenously synthesised from AA (arginine, glycine and methionine) in the liver, pancreas, and kidneys

80
Q

What are the effects of caffeine?

A
  • Improved vigilance and alertness
  • Reduced perception of effort
  • Reduced fatigue and perception of pain
    = Improved performance
81
Q

Outline the 3 proposed mechanisms of how caffeine works.

A

1) Central effect: Caffeine prevents adenosine binding to its receptors in the CNS, reducing sensations of tiredness/fatigue.
2) Metabolic effect: Caffeine stimulates lipolysis directly and indirectly, with possible carbohydrate sparing.
3) Muscle ion effect: Caffeine stimulates calcium release.

82
Q

Explain the “Muscle ion effect” mechanism of caffeine action.

A

Caffeine increases the release of intramuscular calcium ions which are responsible for muscle contractions. However, this seems to happen with very high doses of caffeine.

83
Q

Explain the “Metabolic effect” mechanism of caffeine action.

A

Caffeine stimulates lipolysis (breakdown of triglycerides) directly and via an increase in adrenaline. This may spare muscle glycogen but only in certain conditions:
- 9mg/kg
- High W
- Early in exercise

84
Q

Explain the MOST important “Central effect” mechanism of caffeine action?

A

When adenosine binds to its receptors, this causes feelings of tiredness, fatigue and even pain sensation.

Caffeine has a similar chemical structure to adenosine therefore it stops adenosine binding to the receptors in the brain, reducing the sensations of tiredness and pain thereby delaying fatigue.

Through this mechanism, caffeine can improve performance in a wide variety of sports (endurance, power, high-intensity) without the need of high doses.

85
Q

What is an advantage of using caffeinated gum?

A

most of the caffeine bypasses the gut which increased absorption and decrease GI distress.

86
Q

Are the actions of caffeine influenced by the level of habitual caffeine consumption? But?

A

No - caffeine habitual consumption does not affect ergogenic effects, only when high doses are consumed (6mg/kg BM). When lower doses (3mg/kg) are consumed this is not the case.

87
Q

When should you consider the use of caffeine?

A

 Endurance sports (> 60 min)
 Brief sustained high-intensity
sports (1-60 min)
 Team and intermittent sports –
work rates, skills and
concentration
 Single efforts involving strength or power
 Pre-training energy boost if
carrying fatigue into a session

88
Q

Why is caffeine recommendation dependent on genetics?

A
  • Caffeine metabolization speed differs.
  • Nervous system excitability differs.
89
Q

What is a potential risk of caffeine ingestion?

A

Sleep: It can affect sleep onset and quality which can interfere with the athlete’s recovery between training sessions, or during multi-day competitions.

Hydration: small to moderate doses of caffeine have minimal effects on urine losses or overall hydration. Additionally, caffeine-containing drinks (tea, coffee, coke) contribute to fluid intake.

90
Q

At moderate and high doses of caffeine (>6-9mg/kg), what side effects can occur?

A
  • Anxiety
  • Jitters
  • Insomnia
  • Inability to focus
  • GI unrest
  • Irritability

There is a dependency to caffeine - anxiety and sleep disorders, withdrawal effects can occur.

91
Q

Children (<18yrs) are suggested to limit caffeine intake to …

A

<2.5mg/kg/day