1. EFFECT OF CARBONATED BEVERAGES AND SODIUM BICARBONATE ON
PERCENT BODY FAT ESTIMATION IN THE BOD POD®
By
Bill Coburn MA, ATC, CSCS
East Stroudsburg University of Pennsylvania
A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master
of Science in Athletic Training to the Graduate College of East Stroudsburg University of
Pennsylvania
December 13, 2014

2. SIGNATURE PAGE
This thesis by Bill Coburn submitted to the Graduate College in partial fulfillment of the
degree of Master of Science on December 13, 2014 has been examined by the following
faculty and it meets or exceeds the standards required for graduation as testified by our
signatures below.
KeithVanicPh.D. ThesisChairperson Date
Gerard RozeaPh.D. Date
JohnHauth Ed. D. Date

3. ABSTRACT
A thesis submitted in Partial Fulfillment of the Requirements for the Degree of Masters
of Science to the Graduate College of East Stroudsburg University of Pennsylvania
Student’s Name: Bill Coburn
Title: EFFECT OF CARBONATED BEVERAGES AND SODIUM BICARBONATE
ON PERCENT BODY FAT ESTIMATION IN THE BOD POD®
Date of Graduation: December 13, 2014
Thesis Chair: Keith Vanic, Ph.D.
Thesis Member: Gerard Rozea, Ph.D.
Thesis Member: John Hauth, Ed.D.
Abstract
The BOD POD® can be used to assess body fat percentage. This study was done
to test if the BOD POD® is susceptible to intentional error. Ten Subjects were tested on 2
separate days. The researchers took baseline measurements. The treatment was delivered
by a 12 ounce can of Sprite© or 4 ounces of water with 2 Alka-Seltzer® tablets dissolved
in solution. The subjects were randomized into which treatment they received at the first
session. Repeated tests were performed at ten and thirty minutes. Analysis of variance for
beverage (2.296), time (2.857), and beverage*time (0.102) revealed no significant
difference with either treatment. A T-test score of 0.371 and a Pearson correlation
coefficient of 0.861 revealed that the BOD POD® was reliable. The BOD POD® is
reliable and not susceptible to intentional error through carbonated beverage intake.

4. TABLE OF CONTENTS
INTRODUCTION .............................................................................................................. 1
Hypothesis....................................................................................................................... 2
Purpose of the Study ....................................................................................................... 2
Research Questions ......................................................................................................... 2
Significance of the study................................................................................................. 3
Assumptions.................................................................................................................... 3
Limitations ...................................................................................................................... 3
Delimitations ................................................................................................................... 3
Definitions....................................................................................................................... 4
REVIEW OF LITERATURE ............................................................................................. 5
Air displacement plethysmography................................................................................. 5
The BOD POD ® ............................................................................................................ 8
Human Measurement................................................................................................... 9
Test Procedure ............................................................................................................. 9
Validity.......................................................................................................................... 10
Compared to Other Measures .................................................................................... 10
In Different Groups.................................................................................................... 11
Other Factors Affecting Validity ............................................................................... 12
Reliability .................................................................................................................. 13
Predicted and measured thoracic gas volume ............................................................... 14
Carbonated Beverage and Sodium Bicarbonate Intake ................................................. 14
CHAPTER III ................................................................................................................... 15
METHODS ....................................................................................................................... 15
Participants.................................................................................................................... 15
Research design............................................................................................................. 15
Instrumentation.............................................................................................................. 15
Procedures ..................................................................................................................... 16
RESULTS ......................................................................................................................... 17

5. DISCUSSION ................................................................................................................... 19
REFERENCES ................................................................................................................. 21
APPENDIX A................................................................................................................... 29
APPENDIX B................................................................................................................... 30
APPENDIX C ................................................................................................................... 33
APPENDIX D................................................................................................................... 34

6. 1
CHAPTER I
INTRODUCTION
Over the years, there have been numerous methods for assessing body
composition and percent body fat. The BOD POD®, hydrostatic weighing, dual x-ray
absorptiometry, and skinfold calipers are some of the devices utilized to measure body
composition. They all have their own merits. Some are relatively simple to use. Others
can be quite invasive.
The BOD POD® air displacement plethysmograph is a device that is one method
used in the appeals process for weight certification in high school wrestling. The BOD
POD® is considered a “gold standard.” It is a valid measure when body hair, clothing,
and temperature are controlled (Fields, Hunter, & Goran, 2000) (Fields, Higgins, &
Hunter, 2004) (Higgins, Fields, Hunter, & Gower, 2001). Body hair and elevated body
temperature cause underestimation of percent body fat. Only baggy clothing has been
shown to overestimate body density (Fields, Hunter, & Goran, 2000).
Sodium bicarbonate and carbonated beverages can cause bloating and gas in the
stomach from carbon dioxide gas (Cuomo, et al., 2008) (Fordtran, Morawski, Santa Ana,

7. 2
& Rector, 1984). No one has researched the effects of extra gas in the stomach on the
BOD POD® measurements. It is the intent of the investigation to research the effects of
juice beverages on the percent body fat estimate as calculated by the BOD POD.
Hypothesis
Therefore, it is reasonable to hypothesize that percent body fat as estimated by the
BOD POD® in subjects who ingest Sprite© or Alka-Seltzer® will be overestimated as
compared to the percent body fat estimates of a control group at the p≤.05 level.
Therefore carbonated beverage intake will not be permitted before BOD POD® testing.
The null hypothesis is that beverage ingestion will have no effect on percent body fat
estimation in the BOD POD®.
Purpose of the Study
The purpose of the study is to measure the percent body fat of 10 college students
using the BOD POD® and compare results after ingesting Sprite© or Alka-Seltzer®.
Research Questions
1. What are the effects of Sprite© ingestion on the estimation of percent body fat
as measured by the BOD POD®?
2. What are the effects of Alka-Seltzer® ingestion on the estimation of percent
body fat as measured by the BOD POD®?
3. Does stomach gas significantly affect the estimation of percent body fat by the
BOD POD®?
4. Is the BOD POD® at East Stroudsburg University reliable?

8. 3
Significance of the study
The BOD POD® is a quick, valid way of assessing body composition. It is a form
of appeal for wrestlers wanting to wrestle at a lower weight than their initial assessment
allows. This study will investigate the effects of carbonation on the estimation of percent
body fat as measured by the BOD POD®.
Assumptions
The following assumptions have been identified:
1. Isothermal effects have been identified (clothing, hair, thoracic gas volume, and
body surface area
2. Subjects avoid exercise for 4 hours
3. Subjects avoid other substances that cause stomach gas as well as food for 4 hours
Limitations
The following limitations have been identified:
1. This study will be limited by the population. The population consists of
college students aged 22-32
2. The body compositions of the population will not be controlled.
3. We will use a predicted lung volume instead of measured
Delimitations
This study will be delimited to the following:

9. 4
1. All subjects will wear compression clothing and swim caps.
2. Subjects’ faces will be clean shaven.
3. Subjects’ skin will be dry.
Definitions
1. Air-displacement plethysmography—A method of estimating body volume by the
amount of air displaced.
2. Dual energy x-ray absorptiometry (DEXA)—A method of estimating bone
density and the bone mineral, fat, and mineral-free lean tissue of the body by x-
ray attenuation.
3. Hydrostatic weighing—A method of estimating body volume by measurement of
weight loss when the body is submerged in water. It is also called underwater
weighing or hydrodensiometry.
4. Compartment model—Methods of dividing the body into its component make up.
Two compartments separate the body into fat mass and fat free mass. Four
compartment models divide the body into fat, mineral, lean tissue, and fluid.
5. Adiabatic air—Air that changes temperature from a pressure change.

10. 5
CHAPTER II
REVIEW OF LITERATURE
Air displacement plethysmography
Plethysmography is a method of measuring body volume by subtraction. All of
the plethysmographic methods involve the introduction of a subject into a chamber for a
period of time. Body volume equals the reduction in chamber volume due to the
introduction of the subject. Consequences of the introduction of the subject are changes
in temperature and gas composition (Dempster & Aitkens, 1995).
Boyle’s Law states the “volume of a confined body of gas varies inversely as the
absolute pressure, provided the temperature remains unchanged.” The equation for this
is
𝑃1
𝑉1
=
𝑃2
𝑉2
, where variables 𝑃1 and 𝑉1 represent one pressure and volume while 𝑃2 and 𝑉2
represent a second condition under isothermal air (Hausmann & Slack, 1939). In
adiabatic conditions, air temperature changes with a change in volume. To account for
this, Poisson’s Law is used. The equation is
𝑝1
𝑉1
= (
𝑃2
𝑣2
) 𝛾
where γ is the ratio of the specific
heat of the gas at constant pressure to that at constant volume (Sly, Lanteri, & Bates,

11. 6
1990). The difference in behavior of the gases is important in the design of techniques to
measure body volumes through plethysmography (Dempster & Aitkens, 1995).
Several Germans first used air displacement to study body density in humans
(Gnaedinger, et al., 1963). Siri (Siri, 1956) used helium dilution to improve on the
previous methods. This system had a chamber for the subject. Helium was injected into
the system without altering the pressure or total increase in thermal conductivity of the
gas mixture. The chamber volume was 413L with a 12.5L helium volume meter. The
testing procedure took 15 minutes. The average subject inhales 4Lof oxygen and exhales
4L of carbon dioxide. Changes in volume and gas composition from respiration were
corrected by an equation after the fact. Pressure was equilibrated to normal local
atmospheric pressure in the chamber and helium supply. Horizontal chambers were tried
previously, but were uncomfortable for elderly or ill subjects. The chamber used was
upright, rigid and airtight. The rigidity is needed to avoid volume errors. Two blowers
were used to maintain the gas mixture. A wet-and-dry-bulb psychrometer was used to
measure water vapor. A vacuum system was used to meter the helium while a thermal
conductivity unit measured the monitored helium concentration. The subjects were
placed into the chamber wearing a hospital gown. Mixing of the gases into the chamber
took 3 minutes. The volume changes are measured by a graph. Error estimation was
difficult because of biological and mechanical factors.
Fomon designed a helium-displacement method for infants (Fomon, Jesson, &
Owen, 1963). The chamber consisted of a leucite hood over stainless steel with a metal
water trough that creates an air-tight seal. The volume of the chamber was 30.395L. A

12. 7
perforated stainless steel tray was placed above the fan in the bottom to hold the infant.
There were two pumps to circulate gas. The thermoconductivity cell was the same that
Siri used. The procedure consisted of calibration by measurement of a known volume and
measurement of the subject by the volume of helium injected into the system. The
calibration testing was consistent over time. The subject testing response decreased over
time. The best reproducibility came from testing the same subject on consecutive days.
This method differed from Siri’s by not allowing the chamber to leak to normalize
pressure. The authors did not use a correction in their calculations for residual lung
volume
Gnaedinger (Gnaedinger, et al., 1963) constructed an air-displacement chamber
based on a previous study for animals. The chambers were big enough to contain large
animals. The chamber consisted of a squirrel cage fan for air circulation, thermistor for
temperature measurement, and a hygrometer sensing element for humidity. Calcium
chloride dried the air for the chamber to eliminate vapor pressure corrections. The
densities form air-displacement was significantly correlated with underwater weighing
after the removal of one subject. Doubts about getting accurate measurements of
temperature, pressure and relative humidity led to error in air-displacement methods. The
chamber to subject ratio was 6:1. A smaller chamber may have been more accurate.
Helium was insufficient at reproducibility at measuring lung volume. Previous
attempts at using Boyle’s law to measure body volume were difficult to reproduce
because of temperature changes, respiratory movements and gas and water vapor
exchange. Previous experiments only used 1 chamber. Taylor (Taylor, Aksoy, Scopes, du

13. 8
Mont, & Taylor, 1985) attempted to correct for this. Two chambers were made of
‘Perspex’ cylinders. At one end an annular ring was closed by a door. The other end was
closed by a disk. Rubber O rings sealed the chamber. The doors were sealed with an O
ring and a toggle clamp for a metal to metal seal to prevent volume errors caused by
leaking. The two chambers were connected with the instrumentation to achieve the
harmonic balance and analysis. The subject was placed in the testing chamber while a
reference volume was placed in the reference chamber. Errors and disturbance came from
bodily movements, especially respiratory; air trapped in the gut; and large surface areas.
The BOD POD ®
The BOD POD ® (Life Measurement Instruments, Concord, CA) is a more
practical and functional application of air displacement plethysmography. It is a “pod
shaped” instrument with two chambers. The seat for the subject divides the two
chambers. The subject sits in the front chamber which is the testing chamber. This
chamber is 450L in volume. Subjects enter the front chamber through a door. This door is
sealed by electromagnets during data collection. The rear chamber houses the
measurement devices: transducers, electronics, the breathing circuit, valves, and the air
circulation system. It is 300L in volume (Dempster & Aitkens, 1995).
Between the chambers is a diaphragm. It serves as a volume-perturbation device.
It is controlled to produce sinusoidal perturbations in the 2 chambers. The perturbations
are 350mL in each direction. As one chamber increases, the other decreases. The air
circulation system ensures that gas composition is the same in both chambers. Use of the

14. 9
sinusoidal perturbations and Fourier coefficients eliminate the adiabatic effect on
measurement (Dempster & Aitkens, 1995).
A two-point calibration process is used to account for variations in chamber size
and transducer sensitivity. The pressure measurements with the chamber empty and with
a 50L calibration cylinder allow computations of the constants in the point slope linear
equation. Once these calculations are performed, the system is ready for human
measurement (Dempster & Aitkens, 1995).
Human Measurement
The air close to skin, hair, and clothing will cause isothermal conditions upon
entering the BOD POD®. The air in the lungs will also be close to isothermal. Isothermal
air is more compressible. Because of the small volume of isothermal air and the increase
in compressibility in the system, cloth and hair will be measured as “negative volume”.
For an accurate measurement of body volume, the effects of artifacts must be eliminated
or accounted for. Wearing minimal compression clothing and a swim cap account for hair
and clothing. Excessive body surface area can also cause inaccuracies. It is accounted for
by an automatic calculation (Dempster & Aitkens, 1995).
Test Procedure
The subject is first weighed on a calibrated scale. The two-point calibration is
then performed involving the 50L cylinder and the empty chamber. Each measurement
period lasts 20 seconds. The subject is then introduced for initial volume measurement.
The door is closed and the first 20s measurement period initiates. During this period, the

15. 10
subject relaxes and breathes the ambient air. After this period, the door is opened and
closed. The second measurement period begins once the door is closed. If the two
measurements are within 150mL of each other, the mean score is counted. If the two
measurements differ by more than 150mL, a third trial is used. If two of the three trials
are in agreement, the test is complete. If all three trials are not in agreement, the test is
thrown out and a new test is begun, including the calibration (Dempster & Aitkens,
1995). Thoracic gas volume can be estimated or measured.
Validity
Compared to Other Measures
Dual-energy x-ray absorptiometry is one method of assessing body composition.
When compared to the BOD POD®, its estimation of percent body fat in children is
significantly higher (Lockner, Heyward, Baumgartner, & Jenkins). In adult men the
estimate was higher for the BOD POD® compared to DEXA (Ball & Altena, 2004). The
measurements were not significant in Mexican elderly (Aleman-Mateo, et al., 2007). In
children measured over a period of years, DEXA was found to be more valid, as was
anthropometric measurement (Ittenbach, Buison, Stallings, & Zemel, 2006). In a group of
adults and children, the BOD POD® was more strongly correlated to DEXA than
hydrostatic weighing (Nunez, et al., 1999). In severely obese children, the BOD POD®
underestimated percent fat compared to DEXA (Lazzer, et al., 2008).
Hydrostatic weighing is another method of assessing body composition. Studies
have mixed results concerning the validity of the BOD POD® compared to hydrostatic
weighing. McCrory (1995) found no significant difference in percent body fat from

16. 11
hydrostatic weighing and the BOD POD® in adults. Other studies have disagreed in that
the BOD POD® overestimated percent body fat in adults. The same was seen in children
(Demerath, et al., 2002). The agreement in measurement of percent body fat between the
BOD POD® and hydrostatic weighing has also been seen across a wide range of body fat
percentages (Fields, Hunter, & Goran, 2000). The same results have not been seen in
some athletic populations (Bentzur, Kravitz, & Lockner, 2008) (Moon, et al., 2008). No
difference was seen between the two methods in collegiate wrestlers in a hydrated or
dehydrated state (Utter, et al., 2003). Subjects have said they prefer the BOD POD® to
hydrostatic weighing (Demerath, et al., 2002). The BOD POD® and hydrostatic
weighing are not the same for an individual subject (Demerath, et al., 2002). Differences
were seen between sexes. Body fat percentage was underestimated in men and
overestimated in women in the BOD POD® compared to hydrostatic weighing (Biaggi,
et al., 1999).
Three and Four compartment models are ideal, but can take a long time for
measurement and calculation. They each require separate measurements to measure each
compartment. Estimates of percent body fat by the BOD POD® are accurate to both
models (Moon, et al., 2008) (Aleman-Mateo, et al., 2007).
In Different Groups
In an obese population, the BOD POD® is effective at estimating percent body fat
compared to hydrostatic weighing. Comfort of the patient would suggest the BOD POD®
would be a better method (Ginde, et al., 2005). It can be used to measure obese subjects
with a Body Mass Index over 40 kg/m² (Peroni, et al., 2003). It is also effective at

17. 12
estimating the percent body fat of obese children (Azcona, Koek, & Fruhbeck, 2006).
The only potential problem with using the BOD POD® in obese subjects is the clothing
selection. Compression clothing should be worn during a BOD POD® measurement
(Fields, Hunter, & Goran, 2000). This is not always practical in morbidly obese subjects.
Race is not a factor in estimation of percent fat (Collins, et al., 2004). Previous
studies have shown a difference without a control group. However, Collins et al (2004)
found no difference when comparing to a Caucasian control group. The Schutte equation
should not be used for black subjects because it will overestimate percent body fat
(Collins, et al., 2004). Measurement of African American children is also accurate, as
long as thoracic gas volume is measured and the Suri equation is used (Buchholz,
Majchrzak, Chen, Shankar, & Buchowski, 2004).
The BOD POD is an acceptable form of estimating percent body fat in Caucasian
college men (Moon, et al., 2008). In female athletes, the BOD POD® overestimates
percent body fat (Bentzur, Kravitz, & Lockner, 2008). The same could be said of athletic
high school boys (Moon, et al., 2008). In children, the BOD POD® underpredicts percent
fat at lower fat ranges and overpredicts it at higher fat ranges (Nunez, et al., 1999). The
same was seen in adults (Levenhagen, et al., 1999).
Other Factors Affecting Validity
Clothing will significantly affect the measurement of percent body fat. Hospital
gowns cause an overestimation of the body density leading to a 5.5% underestimation in
percent fat in women (Fields, Hunter, & Goran, 2000). A hospital gown in both sexes
caused an underestimation of 9% body fat (Vescovi, Zimmerman, Miller, & Fernhall,

18. 13
2002). Wearing a t-shirt will underestimate percent body fat by 4.1% in men and 2.9% in
women. A t-shirt and track-suit pants causes an underestimation of percent body fat by
11.8% in men and 10.2% in women (Peeters & Claessens, 2009). Testing of males in
cotton gym shorts caused a 3% underestimation in percent body fat. Compression shorts
are an acceptable substitution for swimsuit briefs, but a tight fitting swimsuit is the
recommended clothing for air-displacement plethysmography (Hull & Fields, 2005).
Testing nude subjects did not improve accuracy over tight swimsuit testing (Vescovi,
Zimmerman, Miller, & Fernhall, 2002).
Scalp and facial hair can have a small, but significant underestimation of percent
body fat. Scalp hair led to a 2.3% underestimation while facial hair led to a 1%
underestimation (Higgins, Fields, Hunter, & Gower, 2001). Excess heat and moisture will
also lead to a small but significant underestimation of percent body fat by 1.8% (Fields,
Higgins, & Hunter, 2004).
Reliability
The BOD POD® has been found to be reliable in estimation of percent body fat.
The between trial reliability is strong in adults (McCrory, Gomez, Bernauer, & Mole,
1995). Within day reliability of test to test has been reported at .98 (Anderson, 2007).
Reliability is also high for subsets within the population from one test to another (Noreen
& Lemon, 2006). The BOD POD® will give consistent results when the same unit is
used. Inter-device variability has been noticed for women, but not for men when the units
are in the same laboratory (Ball S. D., 2005). The authors felt the difference was not
clinically significant. When the units are in different laboratories, there was significantly

19. 14
more variability in percent body fat (Collins, Saunders, McCarthy, Williams, & Fuller,
2004). The BOD POD® is also reliable for the measurement of thoracic gas volume
(Davis, et al., 2007). It is less reliable in children (Demerath, et al., 2002).
Predicted and measured thoracic gas volume
The BOD POD® offers a prediction equation for thoracic gas volume, or a
measurement during the data collection. McCrory(1998) et al found no significant
difference between body composition measurements using measured and predicted
thoracic gas volumes. The results have been different in specific populations. Obese and
overweight women showed a 0.5% overestimation in percent fat loss over a 16 month
program (Minderico, et al., 2008). Percent body fat is also overestimated in African
American children using predicted thoracic volume. The measurement of the thoracic gas
volume by the BOD POD® is valid when compared to the standard gas dilution method
(Davis, et al., 2007).
Carbonated Beverage and Sodium Bicarbonate Intake
Ingestion of Sprite© can cause bloating and belching after ingestion of 300mL.
This ingestion did not affect the physiological functions (Cuomo, et al., 2008). Ingestion
of sodium bicarbonate will also cause carbon dioxide gas production. The full expected
amount would take over three hours after ingestion of 1.8g of baking soda (Fordtran,
Morawski, Santa Ana, & Rector, 1984).

20. 15
CHAPTER III
METHODS
Participants
Ten East Stroudsburg University graduate and undergraduate students ranging in
age between 23 and 32 were used. The subjects received each treatment on separate days
determined at least 24 hours after the previous testing session. The subjects were
randomized to determine which treatment they would receive first. The subjects were all
in good health.
Research design
This study is a repeated measures study.
Instrumentation
The BOD POD® was used to collect percent body fat information from each
subject. The name of the unit was the BOD POD Gold Standard. The model number was

21. 16
BOD POD 2007A. Quality control procedures were performed before each testing
session.
Procedures
The researcher performed quality control procedures on the BOD POD® before
each testing sessions. The subjects were randomized for what beverage was consumed
during the first testing session. A baseline test was performed on each subject in the BOD
POD®. Immediately after the baseline test, the subject consumed the selected beverage.
The beverages were a 12-ounce can of Sprite© or 4 ounces of water with 2 Alka-
Seltzer® tablets dissolved in solution. The subjects were instructed to drink the beverage
as fast as possible, and not to expel any gas until the end of the testing session. Repeated
BOD POD® measures were taken 10 and 30 minutes after beverage consumption. The
second session occurred between 24 and 96 hours after the first testing session based on
lab and subject availability.
Testing setup
Figure 1
Sprite ingestion
Figure 2
Alka Seltzeringestion
Figure 3

22. 17
CHAPTER IV
RESULTS
The results were analyzed using SPSS. A two-way ANOVA was performed as
well as a T-test and Pearson correlation for reliability. The confidence level was set at
0.05.
The baseline Sprite© group mean percent body fat was 27.05 with a standard
deviation of 4.59934. The Sprite© after 10 minutes group had a mean of 27.5500 and a
standard deviation of 4.62703. The Sprite© after 30 minutes group had a mean of
27.5200 and a standard deviation of 4.27988. The baseline Alka-Seltzer® group had a
mean of 27.8000 and a standard deviation of 4.88467. The Alka-Seltzer® after 10
minutes had a mean of 28.0900 and a standard deviation of 4.58365. The Alka-Seltzer®
after 30 minutes had a mean of 28.0200 and a standard deviation of 4.63460.
Statistical analysis involved a two way analysis of variance for beverage, time,
and beverage*time. The tests of within-subjects effects were not significant. Beverage
(F=2.296), Time (F=2.857), and beverage*time (F=0.102). The null hypothesis is not
rejected.

23. 18
The T test and the Pearson correlation tested the reliability of the BOD POD. The
T test result was 0.370043. This is not significant at the .05 level. The Pearson correlation
was 0.8611935. A score above .80 indicates strong correlation. These results indicate the
BOD POD is reliable.
Type 3 Sum of Squares df Mean Square F Sig.
Beverage 5.34 1 5.34 2.296 0.164
Time 1.85 2 0.925 2.857 0.084
Beverage*Time 0.18 2 0.09 0.102 0.903
Table 2. Tests of Within Subject Effects
Tests of Within Subject Effects
Descriptive Statistics
Group Mean
Standard
Deviation N
Sprite Baseline 27.05 4.59934 10
Sprite 10 Minutes 27.55 4.62703 10
Sprite 30 minutes 27.52 4.27988 10
AlkaSeltzerBaseline 27.8 4.88467 10
AlkaSeltzer10 minutes 28.09 4.58365 10
AlkaSeltzer30 minutes 28.02 4.6346 10
Table 1. Descriptive statistics of the groups

24. 19
CHAPTER V
DISCUSSION
This study was performed to look at the effect of carbonated beverage intake and
stomach gas on estimation of percent body fat by the BOD POD® and assess the
reliability of the BOD POD®. Based on the results, stomach gas does not have an effect
on estimation of percent body fat. Neither beverage caused an increase in estimation of
body fat over time. The BOD POD® is reliable.
Statistical analysis showed that the BOD POD® was reliable through both testing
procedures. We were able to see close to the same results over different testing days. This
is in contrast to a study which showed significant differences on between-day reliability
(Anderson, 2007). Other studies have shown within-day reliability (Noreen & Lemon,
2006).
The biggest limitation with the study was our inability to perform a measured
thoracic air volume. The BOD POD® in the laboratory did not have the measurement
tube. The predicted gas volume is appropriate for group means and screenings. It is valid

25. 20
for adults. However, experiments should use the measured thoracic gas volume
(McCrory, Mole, Gomez, Dewey, & Bernauer, 1998). The overestimation of percent
body may have been impeded by using the predicted thoracic gas volume measurement.
In using Sprite© and Alka-Seltzer®, the study was attempting to artificially
inflate the gas volume of each subject. Measurement of the gas volume may have been
affected by this. The gas in the digestive system did not increase the body volume enough
to change the percent body fat significantly. Future research should test using the
measured thoracic gas volume. The correction equations in the BOD POD® may correct
for this.
Some subjects did not comply with some of the delimitations. One subject had
facial hair. Facial hair causes a 1% underestimation of percent body fat (Higgins, Fields,
Hunter, & Gower, 2001). The level of facial hair was maintained throughout the testing
sessions.
The male subjects also did not shave body hair which could cause up to 3%
underestimation of percent body fat. Because this was a longitudinal study and the hair
was kept constant for both trials, the hair did not affect the results (Higgins, Fields,
Hunter, & Gower, 2001).
Another subject had decorations on her bathing suit which could have trapped air
under it. This could cause an increased body density measurement (Fields, Hunter, &
Goran, 2000).

26. 21
REFERENCES
Aleman-Mateo, H., Huerta, R. H., Esparza-Romero, J., Mendez, R. O., Urquidez, R., &
Valencia, M. E. (2007). Body Composition by the four-compartment model:
validity of the BOD POD for assessing body fat in mexican elderly. European
Journal of Clinical Nutrition, 61, 830-836.
Anderson, D. E. (2007). Reliability of air displacement plethysmography. Journal of
Strength and Conditioning Research, 21(1), 169-172.
Azcona, C., Koek, N., & Fruhbeck, G. (2006). Fat mass by air displacement
plethysmography and impedance in obese/non-obese children and adolescents.
International Journal of Pediatric Obesity, 1(3), 176-182.
Ball, S. D. (2005). Interdevice variability in percent fat estimates using the BOD POD.
European Journal of Clinical Nutrition, 59, 996-1001.
Ball, S. D., & Altena, T. S. (2004). Comparison of the BOD POD and dual energy x-ray
absorptiometry in men. Physiological Measurement, 25, 671-678.
Bentzur, K. M., Kravitz, L., & Lockner, D. W. (2008, November). Evaluation of the
BOD POD for estimating percent body fat in collegiate track and field female
athletes: a comparison of four methods. Journal of Strength and Conditioning
Research, 22(8), 1985-1991.
Biaggi, r. R., Vollman, M. W., Nies, M. A., Brener, C. E., Flakoll, P. J., Levenhagen, D.
K., . . . Chen, K. Y. (1999). Comparison of air-displacement plethysmography

27. 22
with hydrostatic weighing and bioelectrical impedance analysis for the assessment
of body composition in healthy adults. American Journal Of Clinical Nutrition,
69, 898-903.
Buchholz, A. C., Majchrzak, K. M., Chen, K. Y., Shankar, S. M., & Buchowski, M. S.
(2004). Use of air displacement plethysmography in the determination of
percentage of fat mass in african american children. Pediatric Research, 56(1),
47-54.
Collins, A. L., Saunders, S., McCarthy, H. D., Williams, J. E., & Fuller, N. J. (2004).
Within- and between-laboratory precision in the measurement of body volume
using air displacement plethysmography and its effect on body composition
assessment. International Journal of Obesity, 28, 80-90.
Collins, M. A., Millard-Stafford, M. L., Evans, E. M., Snow, Snow, t. K., Cureton, K. j.,
& Rosskopf, L. B. (2004). Effect of race and musculoskeletal development on the
accuracy of air plethysmography. Medicine & Science in Sport and Exercise,
1070-1077.
Cuomo, R., Savarese, M. F., Sarnelli, G., Vollono, G., Rocco, A., Coccoli, P., . . .
Buyckx, M. (2008). Sweetened carbonated drinks do not alter upper digestive
tract physiology in healthy subjects. Neurogastroenterol Motil, 20, 780-789.
Davis, J. A., Dorado, S., Keays, K. A., Reigel, K. A., Valencia, K. S., & Pham, P. H.
(2007). Reliability and validity of the lung volume measurement made by the

28. 23
BOD POD body composition system. Clinical Physiology and Functional
Imaging, 27, 42-46.
Demerath, E. W., Guo, S. S., Chumlea, W. C., Towne, B., Roche, A. F., & Siervogel, R.
M. (2002). Comparison of percent body fat estimates using air displacement
plethysmography and hydrodensiometry in adults and children. International
Journal of Obesity, 26, 389-397.
Dempster, P., & Aitkens, S. (1995). A new air displacement method for the determination
of human body composition. Medicine and Science in Sports and Exercise,
27(12), 1692-1697.
Demura, S., Sato, S., & Kitabayashi, T. (2006). Estimation of body density based on
hydrostatic weighing without head submersion in young Japanes adults. Journal
of Sports Sciences, 24(6), 589-596.
Demura, S., Yamaji, S., & Kitbayasji, T. (2006). Residual volume on land and when
immersed in water: effect on percent body fat. Journal of Sports Sciences, 24(8),
825-833.
Fields, D. A., Higgins, P. B., & Hunter, G. R. (2004). Assessment of body composition
by air-displacement plethysmography: influence of body temperature and
moisture. Dynamic Medicine, 3(3), 1-7.
Fields, D. A., Hunter, G. R., & Goran, M. I. (2000). Validation of the BOD POD with
hydrostatic weighing: influence of body clothing. International Journal of
Obesity, 24, 200-205.

29. 24
Fomon, S., Jesson, R., & Owen, G. M. (1963). Determination of body volume from
infants by a method of helium displacement. Annals of New York Academy of
Sciences, 80-90.
Fordtran, J. S., Morawski, S. G., Santa Ana, C. A., & Rector, J. F. (1984). Gas production
after reaction of sodium bicarbonate and hydrochloric acid. gastroenterology, 87,
1014-1021.
Ginde, S. R., Geliebter, A., Rubiano, F., Silva, A. M., Wang, J., Heshka, S., &
Heymsfield, S. B. (2005, July). Air displacement plethysmography: validation in
overweight and obese subjects. Descriptive Epidemiology, 13(7), 1232-1237.
Gnaedinger, R., Reinike, E., Pearson, A., Van Hoss, W., Wessel, J., & Montoye, H.
(1963). Determination of body density by air displacement helium dilution.
Annals New York Academy of Sciences, 96-108.
Hausmann, E. S., & Slack, S. M. (1939). Physics (2nd ed.). New York, NY: D. Van
Nostrand Company, Inc.
Higgins, P. B., Fields, D. A., Hunter, G. R., & Gower, B. A. (2001, May). Effect of scalp
and facial hair on air displacement plethysmographyestimates of percentage of
body fat. Obesity Research, 9(5), 326-330.
Hull, H. R., & Fields, D. A. (2005). Effect of short schemes on body composition
measurement using Air-Displacement Plethysmography. Dynamic Medicine.

30. 25
Ittenbach, R. F., Buison, A. M., Stallings, V. A., & Zemel, B. S. (2006, March-April).
Statistical validation of air-displacement plethysmography for body composition
assessment in children. Annals of Human Biology, 33(2), 187-201.
Lazzer, S., Bedogni, G., Agosti, F., De Col, A., Mornati, D., & Sartorio, A. (2008).
Comparison of dual-energy X-ray absorptiometry, air displacement
plethysmography and bioelectrical impedance analysis for the assessment of body
composition in severely obese Caucasian children and adolescents. British
Journal of Nutrition, 100, 918-924.
Levenhagen, D. K., Borel, M. J., Welch, D. C., Piasecki, J. H., Piasecki, D. P., Chen, K.
Y., & Flakoll, P. J. (1999). A Comparison of Air Displacement Plethysmography
with Three Other Techniques to Determine Body Fat in Healthy Adults. Journal
of Parenteral and Enteral Nutrition, 23, 293-299.
Lockner, D. W., Heyward, V. H., Baumgartner, R. N., & Jenkins, K. A. (n.d.).
Comparison of air-displacement plethysmography, hydrodensiometry, and dual x-
ray absorptiometry for assessing body composition of children 10 to 18 years of
age. Annals New York Academy of Sciences, 72-78.
Martin, A. D., Daniel, M., Clarys, J. P., & Marfell-Jones, m. J. (2003). Cadaver-assessed
validity of anthropometric indicators of adipose tissue distribution. International
Journal of Obesity, 27, 1052-1058.

31. 26
McCrory, M. A., Gomez, T. D., Bernauer, E. M., & Mole, P. A. (1995). Evaluation of a
new air displacement plethysmograph for measuring human body composition.
Medicine and Science in Sport and Exercise, 1686-1691.
McCrory, M. A., Mole, P. A., Gomez, T. D., Dewey, K. G., & Bernauer, E. M. (1998,
April 1). Body composition by air-displacement plethysmography by using
predicted and measured thoracic gas volumes. Journal of Applied Physiology, 84,
1475-1479.
Minderico, C. S., Silva, A. M., Fields, D. A., Branco, T. L., Martins, S. S., Teixeira, P. J.,
& Sardinha, L. B. (2008). Changes in thoracic gas volume with air-displacement
plethysmography after weight loss program in overweight and obese women.
European Journal of Clinical Nutrition, 62, 444-450.
Moon, J. R., Tobkin, S. E., Costa, P. B., Smalls, M., Mieding, W. K., O'Kroy, J. A., . . .
Stout, J. R. (2008, January). Validity of the BOD POD for assessing body
composition in athletic high school boys. Journal of Strength and Conditioning
Research, 22(1), 263-269.
Moon, J. R., Tobkin, S. E., Smith, A. E., Roberts, M. D., Ryan, E. D., Dalbo, V. J., . . .
Stout, J. R. (2008, April). Percent body fat estimations in college men using field
and labarotory methods: a three-compartment approach. Dynamic Medicine, 7, 7.
Noreen, E. E., & Lemon, P. W. (2006). Reliability of air displacement plethysmography
in a large heterogeneous sample. Medicin 7 Science in Sport and Exercise, 1505-
1509.

32. 27
Nunez, C., Kovera, A. J., Pietrobelli, A., Heshka, S., Horlick, M., Kehayias, J. J., . . .
Heymsfield, S. B. (1999). Body composition in children and adults by air
displacement plethysmography. European Journal of Clinical Nutrition, 53, 382-
387.
Oppliger, R. A., Clark, R. R., & Nielsen, D. H. (2000). New equations improve NIR
prediction of body fat among high school wrestlers. Journal of Orthopaedic &
Sports Physical Therapy, 30(9), 536-543.
Oppliger, R. A., Nielsen, D. H., & Vance, C. G. (1991). Wrestler's minimal weight:
anthropometry, bioimpedance, and hydrostatic weighing compared. Medicine and
Science in Sports and Exercise, 23(2), 247-253.
Peeters, M. W. (2012). Subject Positioning in the BOD POD Only Marginally Affects
Measurement of Body Volume and Estimation of Percent Body Fat in Young
Adult Men. PLoS ONE, 7(3), 1-5.
Peeters, M. W., & Claessens, A. L. (2009). Effect of deviating clothing schemes on the
accuracy of body composition measurements by air-displacement
plethysmography. International Journal of Body Composition Research, 7(4),
123-129.
Peeters, M. W., & Claessens, A. L. (2011). Effect of different swim caps on the
assessment of body volume and percentage body fat by air displacement
plethysmography. Journal of Sports Sciences, 29(2), 191-196.

33. 28
Peroni, M. L., Bertoli, S., Maggioni, M., Morini, P., Battezati, A., Tagiaferri, M. A., . . .
Testolin, G. (2003). Feasibility of air plethysmography (BOD POD) in morbid
obesity: a pilot study. Acta Diabetol, 40, S59-S62.
Siri, W. E. (1956, September). Apparatus for Measuring Human Body Volume*. The
Review of Scientific Instruments, 7(9), 729-738.
Sly, P. D., Lanteri, C., & Bates, J. H. (1990). Effect of the thermodynamics of an infant
plethysmograph on the measurement of thoracic gas volume. Pediatric
Pulmonology, 8, 203-208.
Taylor, A., Aksoy, Y., Scopes, J. W., du Mont, G., & Taylor, B. A. (1985). Development
of an Air Displacement Method for Whole Body Volume Measurement of Infants.
Journal of Biomedical Engineering, 7(January), 9-17.
Utter, A. C., Goss, f. L., Swan, P. D., Harris, G. S., Robertson, R. J., Trone, & Gregory,
A. (2003). Evaluation of Air Displacement for Assessing Body Composition of
Collegiate Wrestlers. Medicine and Science in Sport & Exercise, 35(3), 500-505.
Vescovi, J. D., Zimmerman, S. L., Miller, W. C., & Fernhall, B. (2002). Effects of
clothing on accuracy and reliability of air displacement plethysmography.
Medicine & Science In Sports & Exercise, 34, 282-285.

34. 29
APPENDIX A

35. 30
APPENDIX B

36. 31

37. 32

38. 33
APPENDIX C

39. 34
APPENDIX D