# The Bod Pod



## jasone (Sep 18, 2005)

Hey people, I am new to the forum and would like to say hi.
I am training hard and eating right to take myself to the next level.  I've been working out my whole life and and thought I was in great shape, until the Bod Pod.  Calipers show me to be 17-19% on a consistant baisis.  I look like 15% in comparasion to others.  But the bod pod registers me at 27 and 26% a month later.  Could this be the truth?  Sometimes the truth hurts I guess.  According this reading I should be less concerned with my muscles and more concerned with health issues.  I never thought of myself as a fat-ass.  To me 27% is couch potato territory.  Something tells me that this reading though consistant, is not right.  Anyone else have experience with the bod pod.  Do professional bodybuilders use this as a method?  And should I be concerned with health issues even though I look like the picture of health?
Thanks.
jason


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## CowPimp (Sep 18, 2005)

You don't look like 26% body fat to me.  The caliper reading of 17% sounds more accurate to me, based on that picture in your gallery.


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## dbromsey@neo.rr (Oct 27, 2007)

I am a certified personal trainer. I have been measuring clients body fat for years with calipers and I can assure you that your body fat is no where near  26%. My body fat has been measured at 6.3% by an expert certified trainer.  I had the Bod Bod test done at the University of Akron (Ohio) and was measured at 17.6%. Trust me, that's so far off that it's totally laughable.  Any time a formula is used to calculate body fat (I'm sure that they asked you your age, height and weighed you on a scale) I'm suspect of the results.  A body fat test should meaure body fat and the result should not depend upon age, height or weight factors. Unfortunately the only 100% accurate body fat measurement test is via autopsy, and I don't think most of us would enjoy the prerequisite. Don't fret about the BP results.  You're on the right track. To reduce you bf more, do low intensity cardio (65-70% of theoretical max heart rate) for a minimum of 30 minutes a day, AFTER you do your resistance training.  Good luck.


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## vortrit (Oct 27, 2007)

dbromsey@neo.rr said:


> I am a certified personal trainer. I have been measuring clients body fat for years with calipers and I can assure you that your body fat is no where near  26%. My body fat has been measured at 6.3% by an expert certified trainer.  I had the Bod Bod test done at the University of Akron (Ohio) and was measured at 17.6%. Trust me, that's so far off that it's totally laughable.  Any time a formula is used to calculate body fat (I'm sure that they asked you your age, height and weighed you on a scale) I'm suspect of the results.  A body fat test should meaure body fat and the result should not depend upon age, height or weight factors. Unfortunately the only 100% accurate body fat measurement test is via autopsy, and I don't think most of us would enjoy the prerequisite. Don't fret about the BP results.  You're on the right track. To reduce you bf more, do low intensity cardio (65-70% of theoretical max heart rate) for a minimum of 30 minutes a day, AFTER you do your resistance training.  Good luck.



If you'd only been here two years earlier!


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## Tatyana (Oct 28, 2007)

Comparison of the Bod Pod and dual energy x-ray absorptiometry in men
Stephen D Ball et al 2004 Physiol. Meas. 25 671-678   doi:10.1088/0967-3334/25/3/007


     PDF (215 KB) | References 



Stephen D Ball1 and Thomas S Altena2
1 Exercise Physiology Laboratory, Department of Nutritional Sciences, University of Missouri, Columbia, MO, USA
2 Department of Health, Physical Education and Recreation, Southwest Missouri State University, Springfield, MO, USA
E-mail: ballsd@missouri.edu
Abstract. The majority of studies investigating the accuracy of the Bod Pod have compared it to hydrostatic weighing (HW), the long held, and perhaps outdated 'gold standard' method of body composition analysis. Much less research has compared the Bod Pod to dual energy x-ray absorptiometry (DXA), a technique that is becoming popular as an alternative reference method. The purpose of this study was to compare per cent fat estimates by the Bod Pod to those of DXA in a large number of men. Participants were 160 men (32 ± 11 years). Per cent body fat was estimated to be 19.4 ± 6.8 and 21.6 ± 8.4 for DXA and the Bod Pod, respectively. Although the two methods were highly correlated (0.94), the mean difference of 2.2% was significant (p < 0.01). The amount of difference increased as body fatness increased (p < 0.0001). The results of this study indicate that a difference between methods existed for our sample of men. It is uncertain exactly where the difference lies.* Practitioners should be aware that even with the use of technologically sophisticated methods (i.e., Bod Pod, DXA), differences between methods exist and the determination of body composition is at best, an estimation.*Keywords: body composition, air displacement plethysmography, hydrostatic weighing, body fat 

Print publication: Issue 3 (June 2004)
Received 16 March 2004, accepted for publication 22 April 2004
Published 10 May 2004


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## vortrit (Oct 28, 2007)

Tatyana said:


> Comparison of the Bod Pod and dual energy x-ray absorptiometry in men
> Stephen D Ball et al 2004 Physiol. Meas. 25 671-678   doi:10.1088/0967-3334/25/3/007
> 
> 
> ...



I knew that must be old because Southwest Missouri State University is Missouri State University now. They changed the name a couple of years ago.


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## MS-CSCS (Apr 10, 2009)

*In response to "dbromsey@neo.rr" ...*

In response to the certified personal trainer "dbromsey@neo.rr" ... 

Body fat measurements are determined by calculating body density, utilizing the basic formula of body mass divided body volume. For these reasons, both mass(weight) and volume are necessary in order to compute the measurement. Body volume is incredibly difficult to determine, but the BodPod implements air displacement plethysmography (ADP) technology in order to accurately determine the volume of air that the body displaces (using Boyle's Law of physics). From here, body fat can be extraploated to within 2% accuracy (as compared with the "Gold Standard" of hydrostatic weighing). 

Body fat calculated using skin fold calipers is accurate to within 3-5% assuming that the appropriate EQUATION is used (yes, even skin fold calipers require an equation to calculate body denisty). However, most often general formulas are used to determine body fat, which places the accuracy more around 5-7%. Skin fold caliper measurements make the assumption that 50-70% of body fat is stored subcutaneously. It also assumes that this percentage is the same for every individual, regardless of age, gender, ethnicity, etc. Needless to say, skin fold calipers are incredibly inaccurate in special populations, such as elderly or obese individuals. Fluctuations in hydrational status will also siginicantly effect the acuracy of the measurement. On top of which, the accuracy of the measurement is dependent upon the number of sites (the more sites used, the more accurate the measurement) used as well as the experience of the test administrator...

Considering that the BodPod requires 7 calibrations prior to the individual even climbing into the chamber (5 upon turning the machine on and two prior to every test), the BodPod is far more accurate and reliable than the "certified personal trainers" whipping their skin calipers out of a gym bag. Height, weight, and age are also used in the calculation of resting metabolic rate (RMR) which is also produced in the BodPod test. 

I will agree with "dbromsey@neo.rr" on one account- the most accurate calculation of body density is determined via direct measurement (disection). Of indirect body composition measurements, the gold standard of hydrostatic weighing yields a 1-2% error compared with direct measurement. BodPod is within 2% accuracy, Dual-Energy X-ray Absorptiometry within 2-4%, Bioelectrical impedance within 5-7%, and skin fold calipaers between 3-7%.  

Lastly, it should be noted that body fat is composed of two types: essential and nonessential fat stores. Men and women have a minimum amount of body fat that is required for basic physiological functioning, 3% for men and 12% for women. This is called essential fat. AT NO POINT SHOULD AN INDIVIDUAL HAVE A BODY FAT MEASUREMENT BELOW ESSENTIAL FAT LEVELS- this means that men and women should not strive for body fat measurements below 3 and 12%, respectively. While it is possible to have a body fat below these levels, having a body fat so low that it falls into the essential fat range will be accompanied with impaired physiological functioning. Non-essential body fat is storage fat, which provides stored energy, protects internal organs, etc. When body fat is measured, it is taking the sum of both essential and non-essential body fat percentages. Therefore, while people frequently strive for "low" body fat percentages it should not be encouraged to drop into the essential body fat range. 

I hope that this information has been helpful.


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## Built (Apr 10, 2009)

Wow - old thread, but germane to the current "DEXA" discussion. 

I'm 14% bodyfat in my avatar, which was assessed by a friend of mine who is a professional kinesiologist via calipers the same day as my DEXA was taken. Both measurements pegged me at 14% and I feel it is a fair assessment of my physical conditioning at that time. I had veins in my back, delts, lats, arms, all around my navel and into my groin. My legs carry too much fat and that brought up the overall level (sadly, symmetric fat-distribution is a very rare thing).

Most people who saw me at that time were saying "holy crap you must be, like, 6% bodyfat". I've spoken to women who told me they were 9% and had no vascularity at all. 

Most people who get clipped for bodyfat think they are way, WAY leaner than they really are. Case in point - the PT who posted earlier, dbromsey@neo.rr, who was clipped at 6% but bodpod pegged him at 17%. I can see a difference of two to four percentage points, but this is a very profound difference and my money is on the truth being closer to 17% than 6%.


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