APK4125 Lab 7: Air Plethysmography Body Composition Analysis (BodPod)

Plethysmography is simply a measure in the ?, meaning air plethysmography is an assessment of the ?

-change of volume

-change in volume of air

The ? is the ? name of a device that measures air plethysmography

-BODPOD

-brand

The BODPOD is a large egg-shaped ? chamber that is capable of measuring ?

-fiberglass

-pressure changes

The BODPOD was created by ? and ? in 1990 and released by ? as the BODPOD in 1995

-Susan Aitkens and Phil Dempster

-Cosmed

BODPOD is an accurate method of ? measurement that is ?, requires minimal client ?, and minimal ? skill

-body composition

-fast

-compliance

-technician

The general premise of BODPOD is simple and works the same as ?

hydrostatic weighing

After volume is measured in the BODPOD, a ? model is used to estimate their body fat and is therefore an ? method

-2-compartment

-indirect method

The BODPOD has two chambers: ?

reference chamber and measurement chamber

Reference chamber has a volume of ?L

Measurement chamber has a volume of ?L

-300L

-450L

There is a ? located between the two chambers of the BODPOD

diaphragm

During a measurement, the diaphragm ? back and forth to create ? volume changes (of roughly ? mL) that are equal in ? but opposite in ?

-oscillates

-sinusodial

-(of roughly 350mL)

-magnitude

-sign

Volume changes lead to ? and ? pressure changes in the two chambers

small and complementary

The BODPOD computer uses the changes of ? and ? between the reference chamber and the testing chamber to calculate ?

-volume and pressure

-volume

The known volume inside the testing chamber is ?L

450L

Depending on the conditions of ?, the relationship between ?, ? and ? changes

-the environment

-pressure, volume, and temperature

**major problem in measuring volume changes of air in a closed system

Density= ?

mass/volume

Isothermal conditions

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

When air is in isothermal conditions, the relationship between pressure and volume of a ? can be explained by ?

-gas

-Boyle's Law

Boyle's Law

(P1/P2)=(V2/V1)

Adiabatic conditions

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

When air is in adiabatic conditions, the relationships of the pressure and volume of ? can be explained by ?

-gas

-Poisson's equation

Poisson's equation

(P1/P2) =(V2/V1 )^γ

γ is the ratio of ? of the gas

specific heat

When air is inside the BODPOD chamber, it does not act ?

uniformly

Air near the body surface in clothing and hair reacts like ? conditions, air away from the body surface reacts like ? conditions

-isothermal

-adiabatic

Air whose volume is compressed under ? conditions changes its pressure ?% less ? than would occur under ? conditions

-isothermal

-40%

-less compressible

-adiabatic

Throughout the measurement in a BODPOD, it is assumed that the air is acting under ? conditions; for this several things must be ? and ultimately ?

-adiabatic

-controlled

-assumed

There must be a constant ?; for this to be true there must be the same ? of air in the reference chamber that is in the testing chamber

-γ (ratio of specific heat of the gas)

-composition of air

To achieve consistent equal gas composition, an ? is used to mix the air between ? throughout measurement

-air circulation system

-between the two chambers

Since the majority of air in the system is acting under ? conditions, the ? will be calculated assuming these conditions; means that anything that increases air under ? conditions must be eliminated

-adiabatic

-volume

-isothermal

Regardless of how many items are eliminated, air that is in contact with the ? is going to act under ? conditions and this must be considered

-skin

-isothermal conditions

The body surface area is estimated by Dubois formula: ?

BSA (cm²)=71.48Weight(kg)^0.425Height(cm)^0.725

BSA is multiplied by ? to yield surface area ? which is automatically computed and used to correct the ? air that cannot be ?

-constant k

-artifact

-isothermal

-eliminated

The average ? volume (?) needs to be considered (can be measured or predicted)

thoracic gas volume (Vtg)

The BODPOD predicts Vtg based on ? and ? of the participant

height and weight

The range for total thoracic volume is ?L to ?L

3L-4.5L

Individuals with higher average Vtg (>?L) will be ? by the BODPOD

Individuals with lower average Vtg (

-(>4.5L) overpredicted

-(<3.0L) underpredicted

Ultimately, the BODPOD takes a measure of ? change inside the measurement chamber by comparison of the reference chamber with air under ? conditions and then factors in the ? and ?

-volume

-adiabatic

-surface area artifact and Vtg

Final Body Volume=?

Body Volume(raw) - Surface Area Artifact + 40%Vtg

The reason Vtg is multiplied by ?% is because lung volume appears this much ? than it is because the air in the lungs is acting under ? conditions

-40%

-larger

-isothermal

Since ? is used to estimate body composition, the estimations of ? model are still assumed:

FFM:

FM:

-density

-2-compartment

-FFM: 1.100g/cm3

-FM:0.900g/cm3

? ?kg weights are used for calibration beside the scale

2 10kg

Testing chamber can accommodate up to ?lbs clients and ?' tall clients

-550lbs

-7'

The volume calibration cylinder has a value of ?L

50.118L (overall volume varies around 50L)

When the client sits back, it changes the ? of the diaphragm when then creates the changes in ? and ? that allow for precise measurement

-surface area

-pressure and volume

Clothing requirements for women and men

Women: form fitting, spandex-type swimwear or single layer compression shorts (no padding) and single layer (not padded) sports bra; remove all jewelry

Men: form fitting spandex-type swimwear or single layer compression shorts (no padding) and no shirt; remove all jewelry

Both: a swim cap will be reqired to be worn during testing

Compliance conditions prior to testing:

-no exercise for at least ? hrs prior to testing

-do not eat/drink liquids for at least ? hrs prior to testing

-avoid ? or ? supplements prior to testing

-void ? before testing

-do not apply ? or ? to the skin the day of

-if you shave any part of the body, do so ?

-no exercise for at least 2 hrs prior to testing

-do not eat/drink liquids for at least 2 hrs prior to testing

-avoid caffeine or thermogenic supplements prior to testing

-void bladder before testing

-do not apply skin creams or lotion to the skin the day of

-if you shave any part of the body, do so the day of the test

Minimal amount of "essential fat" is ?-?% for men, and ?-?% for women

-3-5% for men

-12-15% for women

Risky (high) body fat rating

Men: >30%

Women: >40%

Excess fat rating

Men: 21-30%

Women: 31-40%

Moderately lean body fat rating

Men: 13-20%

Women: 23-30%

Lean body fat rating

Men: 9-12%

Women: 19-22%

Ultra lean body fat rating

Men: 5-8%

Women: 15-18%

Risky (low) body fat rating

Men: <5%

Women: <15%

Body composition normative data (men)

Body composition normative data (women)