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EXCI 445 SPORT NUTRITION > CHAPTER 4 > Flashcards

CHAPTER 4 Flashcards

1
Q

What is energy?

A

capacity to do work aka mechanical energy

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2
Q

Is work=force x d mechanical energy?

A

yes

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3
Q

Is power = work/time mechanical energy?

A

yes

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4
Q

What is mechanical energy?

A

muscle contraction

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5
Q

What is chemical energy?

A

glucose and ATP

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6
Q

What is energy expenditure equation?

A

energy/time in kj or kcal/unit

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7
Q

calorie

A

Energy needed to raise the temperature of 1 g water 1oC.

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8
Q

Calorie

A

expressed on food labels

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9
Q

Joule

A

energy required to move a mass of 1 g at a velocity of 1 m/s.

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10
Q

1 cal = ______ Joules

A

4.186

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11
Q

1 kilocalories = ____ kilojoules

A

4.186

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12
Q

Is energy lost when converted from one form to another? Give example

A

no

CHO and fat combustion cause muscle contraction and rest goes to heat energy

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13
Q

Joule provides what kind of energy

A

mechanical

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14
Q

Energy efficiency: chemical or mechanical energy?

A

BOTH

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15
Q

Energy efficiancy

A

% of total work

20% is what we use for human work

remaining 80% as heat (homeostasis)

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16
Q

Gross efficiency

A

ratio of total work to energy expended

GE=work/energy expended X 100%

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17
Q

For GE: as exercise intensity increases, energy expended __________(increases /decreases). ultimately, GE gets bigger or smaller?

A

energy expended decreases, so your GE will increase

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18
Q

Net efficiency

A

baseline is the energy expended at rest to resolve GE getting bigger

NE = work accomplished / (energy expended-resting energy ependiture) X 100%

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19
Q

Work efficiency

A

another way to calculate baseline where baseline is the energy cost of unloaded work

WE = work accomplished/ (energy expended-energy expended in unloading condition) X 100%

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20
Q

Delta efficiency

A

change in energy expenditure relative to the change in actual work accomplished per minute

DE: delta work accomplished/delta energy expended X 100%

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21
Q

Atwater factors for CHO, fat and protein

A

CHO=4kcal/g
Fat=9kcal/g
Protein=4kcal/g

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22
Q

Coefficient of digestibility for CHO, fat and protein

A

Carb 97%
Fat 95%
Protein 92%

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23
Q

Does fibre increase or decrease digestibility?

A

Fibre decreases digestibility

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24
Q

Energy content for fat depends on

A

structure of FA and TAG

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25
Q

Energy content for protein depends on

A

type of protein and ntirogen content

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26
Q

If theres nitrogen in protein, does it give more energy or less energy?

A

less,

nitrogen DOES NOT PROVIDE energy

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27
Q

What does the direct calorimeter test?

A

metabolic rate of person

28
Q

Disadvantage of direct calorimetry

A

Not practical for field studies and assessment of energy expenditure during sport and exercise
Some have developed direct calorimetry suits with the same principles but allows measurements to be conducted outside. Suit may impede movement however

29
Q

How does the direct calorimeter prevent heat loss?

A

recirculated o2 and co2, water filtered out, oxygen is added

30
Q

What does the closed circuit spirometry measure? How???

A

02 uptake and co2 production

aka energy expenditure

measured by seeing the difference in 02 uptake and co2 given off into the filter and by measuring TEMPERATURE

31
Q

Disadvantage of closed circuit calorimeter

A

not suitable for exercise esp high intensity

32
Q

What does respiration chamber (indirect) measure?

A

complete energy balance

33
Q

Disadvantage to resp chamber

A

expensive, unrealistic, requires highly trained

34
Q

Does the resp chamber measure heat directly?

A

NO

35
Q

What does the open-circuit spirometry measure?

A

changes in inhaled and exhaled ambient air

36
Q

WHat can do you with results of open circuit after?

A

calculate RER

which is VCO2/VO2

37
Q

Is open circuit indirect or direct?

A

indirect

38
Q

Is resp chamber indirect or direct?

A

indirect

39
Q

Explain douglas bag

A

-large plastic bags collect expired air
-after collection, bags are closed and then emptied into gas meter to measure total volume
-sample gas from bags analyzed for O2 and CO2 concentrations
Analyzers such as that seen in this picture can analyze CO2 and O2 breath by breath
Therefore, can look at rapid changes - can look at changes every few seconds to several minutes

40
Q

REE is measured by direct or indirect calorimetry?

A

indirect

41
Q

Conditions for resting energy expenditure

A 
Resting in supine position >30 min before
Fasting >12 h
No exercised for >24-48 h
No caffeine >4 h
No nicotine >1 h
No alcohol >48 h
Darkened, quiet, thermoneutral environment
Normal acid-base balance
42
Q

What is RQ, what does it do?

A

resp quotient - ratio of CO2 production and O2 production that provides indication of primary substrate utilized during steady state exercise.

43
Q

RQ of CHO

A

1 because oxygen molecules = co2 molecules

44
Q

RQ of lipids

A

7 ish

45
Q

What is expired represents the oxidation processes in the tissues for which 2

A

oxygen and N2

46
Q

What is expired DOES NOT represents the oxidation processes in the tissues for which, and why?

A

CO2 because co2 release is based on bicarbonate pool. and the pool is sensitive to changes in acid base balance ebcause shifts in bicarbonate buffering system affects dissociation of gases

47
Q

WHen is RER over 1?

A

hyperventilation (through lactic build up, you release co2) and lipogenesis

48
Q

What is doubly labelled water?

A

administer a bolus dose of 2 stable isotope water
difference between the 2 excretion rates repesent the co2 production rate, then co2 can be used to calculate EE

advantage: can be done on free living people

49
Q

disadvantage of doubly labelled water

A

expensive, only suitable for measurement over days or weeks

50
Q

Sedentary (little or no exercise):

A

1.2

51
Q

Lightly active (1-3 days/week):

A

1.375

52
Q

Moderately active (3-5 days/week):

A

1.55

53
Q

Very active (6-7 days a week):

A

1.725

54
Q

Extra active (physical job or 2x training):

A

1.9

55
Q

BMR

A

measured lowest oxygen uptake in resting thermoneutral conditions

56
Q

RMR

A

energy required for the maintenance of normal body functions and homeostasis in resting conditions

57
Q

if you are sedentary is your RMR larger or smaller than people who are very active?

A

larger

58
Q

factors that affect energy balance

A 
Weight
Body composition
Sex
Activity intensity/type
Age
Genetics
59
Q

what is energy balance?

A

balance calculated over longer periods

60
Q

what’s a good indicator of energy balance?

A

Wt

61
Q

BMR units

A

J/s

62
Q

which efficiency is best at rest

A

gross

63
Q

which efficiency is best during exercise

A

delta efficiency

64
Q

labeled bicarbonate

A

Constant infusion of bicarbonate labeled (13C or 14C) to reach equilibrium with body’s CO2 pool

  • then any change results in changes in labeled CO2 production
  • applied for short period (hours/days)
65
Q

heart rate monitoring

A
  • HR – linear relationship with O2 uptake at submax exercise
  • less accurate especially at low levels of EE as at rest only slight movements increase HR but EE is same, emotions also change HR but not O2
66
Q

accelerometers

A

Movement along 1, 2 or 3 axes
Correlate well with EE but may underestimate
Rough estimate or indication of EE

67
Q

activity records

A

rough estimation, ppl tend to overestimate or underestimate PA

EXCI 445 SPORT NUTRITION (5 decks)

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