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EXERCISE PRESCRIPTION LAB > LAB7- Air Plethysmography Body Composition Analysis > Flashcards

LAB7- Air Plethysmography Body Composition Analysis Flashcards

1
Q

plethysmography

A

a measure in the change of volume

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2
Q

air plethysmography

A

an assessment of the change in volume of air

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3
Q

BODPOD

A

the brand name of a device that measures air plethysmography
-a large egg-shaped fiberglass chamber that is capable of measuring pressure changes
-accurate method of body composition measurement that is fast (after calibration), requires minimal client compliance + minimal technician skill

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4
Q

the general premise of BODPOD works the same as ____

A

hydrostatic weighing

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5
Q

how does BODPOD work in simple terms

A

-a client’s weight is measured on a scale
-their volume is measured in the BODPOD
-using a 2-compartment model their body fat is estimated

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6
Q

describe chambers of BODPOD

A

has a reference chamber + a measurement chamber

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7
Q

volume of reference chamber

A

300L

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8
Q

volume of measurement chamber

A

450L

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9
Q

what is found in between the reference chamber + measurement chamber

A

a diaphragm

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10
Q

what does the diaphragm do during a measurement

A

oscillates back + forth to create sinusoidal volume changes (of roughly 350 mL) that are equal in magnitude but opposite in sign

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11
Q

sinusoidal volume change created by the oscillation of the diaphragm

A

350 mL

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12
Q

volume changes created by diaphragm lead to what in the 2 chambers

A

small + complementary pressure changes in the 2 chambers

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13
Q

how does the BODPOD computer calculate volume

A

uses the changes of volume + pressure between the reference chamber + the testing chamber to calculate volume

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14
Q

known volume inside the testing chamber

A

450L

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15
Q

what is the major problem in measuring volume changes of air in a closed system

A

depending on the conditions of the environment, the relationship between pressure, volume, + temperature changes

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16
Q

density formula

A

m / v

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17
Q

isothermal conditions

A

the temperature of the system stays constant because there is a transfer of heat between the system + the surroundings

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18
Q

when air is in isothermal conditions, the relationship of pressure + volume of a gas can be explained by

A

Boyle’s law (Boyle-Mariotte law)

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19
Q

Boyle’s law equation

A

P1 / P2 = V2 / V1

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20
Q

adiabatic conditions

A

the temperature of the system is not constant + there is no transfer of heat between the system + the surroundings

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21
Q

when air is in adiabatic conditions, the relationship of the pressure + volume of a gas can be explained by

A

Poisson’s equation

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22
Q

what is ɣ in Poisson’s equation

A

the ratio of specific heat of the gas

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23
Q

Poisson’s equation

A

P1 / P2 = (V2 / V1)^ ɣ

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24
Q

Boyle’s law = isothermal/adiabatic

A

isothermal

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25
Poisson's equation = isothermal/adiabatic
adiabatic
26
when air is inside the BODPOD chamber does the air act uniformly
no
27
air near the body surface in clothing + hair reacts like isothermal/adiabatic conditions
isothermal
28
air away from the body surface reacts like isothermal/adiabatic conditions
adiabatic
29
we will assume we are in isothermal/adiabatic
adiabatic -assume things are not constant
29
**air whose volume is compressed under isothermal conditions changes its pressure ____ % less than air compressed under adiabatic conditions
40% less
29
air whose volume is compressed under isothermal conditions changes its pressure 40% less than air compressed under adiabatic conditions ^^what does this mean
means air under isothermal conditions is 40% more compressible than under adiabatic conditions
30
throughout the measurement in a BODPOD, it's assumed that the air is acting under isothermal/adiabatic conditions
adiabatic -for this to be the case, several things must be controlled for + ultimately assumed
31
we assume adiabatic conditions- for this to be true what must we do to ɣ
there must be a constant ɣ
32
how do we achieve a constant ɣ
there must be the same composition of air in the reference chamber that's in the testing chamber -to achieve this an air circulation system is used to mix the air between the 2 chambers throughout measurement
33
to assume adiabatic conditions, what must we eliminate
anything that increases air under isothermal conditions (excess hair, baggy clothing, etc.)
34
regardless of how many items are eliminated like exccess hair + clothing...
air that is in contact with the skin is going to act under isothermal conditions -this needs to be considered
35
what equation estimates body surface area
Dubois formula
36
how do we use body surface area
BSA is multiplied by a constant k to yield the surface area artifact which is automatically computed + used to correct the isothermal air that can't be eliminated
37
what else must we consider to assume adiabatic conditions
average thoracic gas volume (V of TG)
38
BODPOD predicts V of TG (average thoracic gas volume) based on what 2 things
height + weight
39
individuals with lower average V of TG will be over/underpredicted by the BODPOD
underpredicted
40
individuals with a higher average V of TG will be over/underpredicted by the BODPOD
overpredicted
41
it is recommended that average V of TG is measured or predicted
measured -more precision
42
in this lab, average V of TG will be measured or predicted
predicted
43
most people's V of TG falls within what values
3-4.5 L
44
ultimately what does the BODPOD do
takes a measurement of volume change inside the measurement chamber by comparison of the reference chamber with air under adiabatic conditions + then factors in the surface area artifact + V of TG
45
**formula to solve for final body volume
final body volume = raw body volume - surface area artifact + 40% V of TG
46
why do we multiply V of TG by 40% in the equation for final body volume
the lung volume appears 40% larger than it is because the air in the lungs is acting under isothermal conditions
47
what is final body volume used to calculate
density
48
because density is used to estimate body composition...
the estimations of 2-compartment model are still assumed
49
fat mass has a density of
0.9 g/cm^3
50
fat-free mass has a density of
1.1 g/cm^3
51
equipment- scale
-highly accurate -10kg weights for calibration beside scale
52
**for calibration what is used
two 10kg weights beside scale
53
testing chamber is able to accomodate up to ____ lb clients
550 lb
54
testing chamber is able to accomodate up to ____ tall clients
7' tall
55
testing chamber has a safety button inside
56
**volume of calibration cylinder in testing chamber
50.118 L
57
the volume of the cylinder in the testing chamber varies around ____ L
50L
58
diaphragm
creates the changes in pressure + volume that allow for precise measurement
59
clothing requirements- women
-form fitting -spandex-type swimwear or single layer compression shorts (no padding) + single layer (not padded) sports bra -remove all jewelry
60
clothing requirements- men
-form fitting spandex-type swimwear or single layer compression shorts (no padding) + no shirt -remove all jewelry
61
clothing requirements- both gender
-a swim cap will be required to be worn during testing -the swim cap will be provided or you can bring your own -use disinfectant spray between participants
62
prior to testing- exercise
do not exercise for at least 2 hours prior to testing
63
prior to testing- eat/drink
do not eat/drink for at least 2 hours prior to test
64
prior to testing- caffeine
avoid caffeine or thermogenic supplements prior to testing
65
prior to testing- bladder
void bladder prior to testing
66
prior to testing- skin creams/lotion
do not apply skin creams/lotions before test
67
prior to testing- shaving
if you shave any part of your body, do so the day of the test if possible
68
during testing
there is a blue emergency button inside the BODPOD behind the left leg to unlock the magnetic door
69
normative data for % body fat- men
20-29: 14.8% 30-39: 18.4% 40-49: 20.8% 50-59: 22.3% 60-69: 23% 70-79: 22.9%
70
normative data for % body fat- women
20-29: 20% 30-39: 21% 40-49: 23.6% 50-59: 26.6% 60-69: 27.5% 70-79: 26.3%

EXERCISE PRESCRIPTION LAB (10 decks)

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