The Tape Test: It is more sensible than you think!
By Nick Barringer, PhD.
When it comes to debated military assessments, there may be none that cause more fervent discourse than the dreaded “tape test”. The methods used in the body composition assessment in AR 600-9 has kept barracks lawyers in practice since it was rolled out in 1986. Recently, the Army Times ran a piece dubbed the “ultimate take down of the senseless tape test”.
The author’s key arguments are based off of another Army Times article from 2013 aptly titled “Experts: Tape test has huge margin of error” the article compared the tape test to the “gold standard” of hydrostatic weighing. The investigators reported “The tape test was wrong every time, and in nine out of 10 cases, the tape method measured troops’ body fat percentages higher — the worst was a 66 percent difference between the scores. The closest was nearly 12 percent off.”
The “take down” article closes by pointing out there are better assessment tools with higher “precision” and the final battle cry for getting rid of the tape test by saying “We have the technology. We choose to ignore. That is senseless.”
So the author’s “take down” argument is 1.) The tape test is “primitive and imprecise” 2.) There are better alternatives available.
But I beg to differ…
Although I believe that the author had the best intentions in writing the “ultimate takedown”, as the saying goes “nothing ruins a good combat story like an eye witness” and in this case nothing ruins a mostly anecdotal argument like actual science. So now let us look more carefully at the argument, compare it to the research, and see if we can’t elucidate some clearer facts.
Argument 1: The Tape Test is grossly inaccurate
In 1981 the Services were directed to develop body composition standards with the three major concerns being: 1) body composition was an integral part of physical fitness 2) body composition is a determinant of appropriate military appearance and 3) body composition is a determinant of general health and well-being of military personnel.
In 1982, in response to the directive developed the following criteria:
- a) no skinfold measurements
- b) emphasizes circumference measurements at easily locatable anatomic sites
- c) not to exceed 4 measurements(excluding height and weight)
- d) able to be executed by non-technically trained personnel
- e) does not require elaborate or unavailable equipment
- f) common equation for all race/ethnic groups
- g) measurements should be avoided that require undressing beyond the Army sport ensemble
- h) selected equations must have a correlation coefficient of at least 0.80 with hydrostatically determined percent body fat, and a standard error of the estimate not greater than 4.0 % body fat
- i) equations should give comparable results in the three major race/ethnic groups
Based on these criteria, a study was carried out at Fort Hood, TX and Carlisle Barracks, PA on 1,194 males and 319 females between 25 Jun and 1 Nov 1984. The Soldiers were hydrostatically weighed and circumference measurements were taken. Based on this study, the Army circumference formula for the tape test was built. When the body fat estimates from the tape test were compared to the “gold standard” of hydrostatic weighing the values provide were an R=0.817 with Stand Error of 4 for men and an R=0.820 and a Standard Error of 3.5 for women. The assessment was also cross validated in a population of Navy personnel.
So to better explain: in statistics you have the R or correlation coefficient which tells you how well one test correlates to the other with 0 being no correlation and 1 being a perfect correlation. Realistically the only way you get 1 is if you are comparing something to itself so anything 0.80 and above is considered a strong correlation. For perspective, the correlation coefficient for asbestos exposure and cancer, particularly mesothelioma, is reported around 0.80.
If a 0.80 correlation is strong enough for lawyers to make TV commercials looking for asbestos exposure victims because they know the case will be a slam dunk, the tape test’s values of 0.817 and 0.820 ain’t too shabby.
The author’s description of the tape test as “primitive and imprecise” should be replaced with the more appropriate adjectives of simple and effective.
Argument 2: There are better alternatives available
The main example the author uses to report the flaws of the tape test is hydrostatic weighing on 10 Soldiers from the Army Times article from 2013. The irony of the argument is the author is trying to use 10 Soldiers completing hydrostatic weighing in a non-research setting to trump a test that was developed using hydrostatic weighing of 1,513 Soldiers in a research setting, further cross validated using additional Navy personnel, and revalidated by more advanced methods such as Dual-energy X-ray absorptiometry.
It is important to realize all body composition assessments are estimates. The only way to directly measure body fat is to dissect a cadaver, cut out all the fat, and weigh it. So every assessment has its flaws.
For hydrostatic weighing, if you drink a bunch of fluid or just ate a large meal, you would be denser and therefore the extra weight would be interpreted as lean mass and a lower body fat percentage. That is why how the test was administered makes a difference. In a research setting, such as the one used to develop the tape test, the researchers control for things like subject hydration status etc. In the 10 subjects the Army Times assessed we don’t know if these things were taken into account.
Bioelectrical Impedance (BIA), as seen on some types of bathroom scales, estimates body fat based on body water. So hydration status and the quality of the machine can significantly impact the estimate. Skin-fold calipers requires a trained professional with knowledge of the appropriate anatomical sites and technique. The Army used skin-fold calipers in the past but found the tape test to have less variability, be more efficient, and according to Dr.Friedl better serve the Soldier trying to lose weight since intraabdominal fat seems to mobilize more quickly than subcutaneous fat as he reported “waist circumference based military equations are relatively sensitive to changes in criterion-measured body fat for male and female soldiers during basic training and male soldiers during Ranger training”.
A sensible test.
Look, I’m not saying the tape test is the best body composition assessment method available because it is not. But that is not what the test was designed to be. It was designed to determine if a Soldier is over-fat. It was designed to be an efficient and economical assessment that could be completed by non-technically trained personnel. It was designed to have a strong correlation to recognized “gold standards” in body composition assessment and work for all major ethnicities. Even in the Army Times report from 2013, they did not report that any of the 10 Soldiers failed the tape test that shouldn’t have. So the tape test still did its job. When one takes the original daunting requirements into consideration, actually reads the level of research that went into developing the tape test, and compares it to the fiscal and time costs of other body composition assessments; the tape test is the only sensible answer.
Disagree? Then name a more sensible test in the comments.
Author’s note: The research I mentioned and that is hyperlinked in the article just scratches the surface of the background of body composition assessments in the military. If you want to truly appreciate the work, go to Google Scholar and enter the names of Dr. J.A. Hodgdon, Dr. J.A. Vogel, and Dr. K.E. Freidl. For the cliff notes read Dr. Freidl’s review here.