Phys: Principles of Nutrition

Question 1

What is the definition of nutrition?

Answer 1

The provision of nourishment to cells, tissues, organs, systems and the body as a whole

Question 2

What is the IOC consensus of nutrition?

Answer 2

The amount, composition and timing of food intake can profoundly affect sports performance

Question 3

What are the questions that should be considered when thinking about the nutritional needs of the performer?

Answer 3

Does that fuel allow you to compete at that level of intensity?
Does it help achieve your goals?
Can the nutrition give the desired response during the session?
What are the effects of not taking the nutrients?

Question 4

What does the Burke 2002 guidelines suggest about sports nutrition?

Answer 4

• meet the energy requirements whilst maintaining ideal physique (not all sports needs 6 packs and such as rugby)
• Practising nutritional strategies so the gut gets accustomed to certain things and the volume that we take in
• Well considered decision over supplement use

Question 5

What is the macronutrient energy distribution?

Answer 5

Sportspeople need an increased carbohydrate (60%) and reduced ‘relative’ protein uptake (15%), however a sportsperson is usually on a much greater caloric need compared to the average UK diet therefore the 15% protein is probably more than all the other people
-measure everything in grams per kilogram g/kg to make everything relative to modyweight

Question 6

What are the needs for carbohydrate?

Answer 6

• Recommended relative to our period of training
• Very high intensities can require 8-12g/kg a day
• Fluctuate between the intensities of the days

eg. 75kg athlete (450g-750g) so (1800-3000kcal)

needs to be a mix of complex and simple carbohydrates

Question 7

What is the goal of pre-exercise feeding?

Answer 7

-To optimise the supply of muscle glycogen and blood glucose late in the exercise bout

Question 8

What are the recommendations of pre exercise feeding?

Answer 8

• Eat an easy to digest high CHO meal
• Ideally 3 to 4 hours before exercise

-Eating too many carbohydrates before an event could lead to starting competition hypoglycaemic so insulin will be removing it from the bood

Question 9

What are the potential effects?

Answer 9

• Promotes extra muscle glycogen synthesis
• Replenish liver glycogen
• Increases CHO oxidation during exercise

Question 10

How much glycogen is stored in the body?

Answer 10

approx 500g in muscle

approx 100g in liver

Question 11

What are the suggested carbohydrates during exercise?

Answer 11

30-60g (120-240kcal) of CHO every h to improve performance
-Hydration, maintainence of blood glucose, muscle/liver glycogen sparing prevention of GI distress

• Protein and fat consumed during exercise can delay gastric emptying
• Nutritional training

Question 12

What does the addition of glycogen during performance have an effect on performance?

Answer 12

Receiving glycogen from an exogenous source can increase performance increases from the sparing of liver glycogen

Concentration of performance drink should not be so high (5-8%) to prevent dehydration but will boost performance

Question 13

What is the best way to use CHO during exercise?

Answer 13

• Using multiple transportable carbohydrate
• We have many different glucose uptaking mechanisms
• Maximum amount to transport carbohydrate using one mechanism is 1.1g/min
• Using fructose transporters aswell as glucose transporters can increase intake to around 1.7g/min if both used at the same time
• Only really needed if duration is high (road cycling)

Question 14

How much more effective is it using glut/fruct performance drink?

Answer 14

7. 6% more effective than a regular glucose drink

- glucose drink is 9.1% more effecting than no drink at all

Question 15

What are the suggested CHO post-exercise?

Answer 15

• Delaying CHO intake following intense exercise may reduce muscle glycogen storage and impair recovery
• Athletes should consume 3g/kg/BW in 2hour period following exercise
• First 30mins produces rapid rate of resynthesis

Question 16

What do the rates of glycogen resynthesis suggest about refueling?

Answer 16

Suggests that there are increased rates in glycogen resynthesis during the first 2 hour window.

However there is no significant different in the amount of glycogen resynthesised over the 24hour window if diet is good throughout the day

Question 17

What is the enzyme used to resynthesise glycogen?

Answer 17

Glycogen Synthase

Question 18

What is glycogen synthase induced by?

Answer 18

• Glycogen depletion
• Muscular contraction
• Release of Insulin

all of the above increases GLUT4 translocation

Question 19

What are the protein requirements for:

• Healthy adult
• Endurance trained
• Resistance trained

Answer 19

Healthy adult: 0.75g/kg/BW

Endurance trained: 1.2-1.7g/kg/BW

Resistance trained: 14-2.0g/kg/BW

Question 20

What did Burke 2016 say about protein requirements?

Answer 20

Individuals should no longer be solely categorised as strength or endurance athletes and provided with static daily protein intake targets

Question 21

What did Moore 2018 suggest about protein requirements?

Answer 21

0.3g/kg/BW after key exercise sessions and every 3-5hours over multiple meals

Question 22

What is the optimal hydration pre exercise?

Answer 22

• 400-600ml fluid 2 hours before exercise
• Pre exercise meal 2-4hours previous

-Do not enter period of sleep in a dehydration state

Question 23

What are the key reasons to hydration during exercise?

Answer 23

• Maximise performance by limiting fluid losses
• Maintaining fluid levels and/or provision of CHO will be important
• Maintainance of plasma volume will maximise endurance capacity and thermoregulatory capacity
• Minimising gastric distress and maximsing fluid absorption

Question 24

What are the features of the optimal hydration for exercise?

Answer 24

• High sodium
• Can take the form of water plus solid foods depending on recovery period
• Never only water
• 150% fluid losses
• Caffeine post exercise has a more potent diuretic effect
• Palatability of drink is important

Question 25

What are the volumes of rehydration after exercise? Shirreffs 1996

Answer 25

Tested fluid volumes of 50,100,150,200% of body mass loss in the hour after exercise
-Only volumes greater than losses achieved euhydration (150-200%)

150% fluid losses replaced by a low sodium drink achieved rehydration without resulting in large reductions in plasma sodium and osmolality

-Only increasing the volume from 150%-200% will show a benefit in the high sodium group (reduction in urine output)

Question 26

What is the relation between rehydration and sodium after exercise?

Answer 26

Maintaining sodium balance has a strong relationship 5-6hours after rehydration with maintaining water balance