Researched
and Composed by
Gabriel “Venom” Wilson, BSc. (Hons), CSCS
Introduction
Testing ones body fat is an important part of a quality bodybuilding
program. Having knowledge of ones body fat can be used in determining
ones progress and in calculations vital to a bodybuilder’s diet (i.e.,
daily caloric intake). However, there are few guides available that
provide clear and accurate instruction.
The easiest and most practical method of measuring ones body fat
utilizes body fat calipers (see figure 1) to measure subcutaneous fat
(fat directly beneath the skin) combined with good technique and simple
math formulas.
Figure 1
Body Fat Calipers
The goal of this guide is to inform readers on proper techniques used in
the body fat testing, caliper method, so that they develop the skills
necessary to produce accurate and precise results.
The HYPERplasia
Challenge
On ABCbodybuilding.com, we regularly hold an 8 week bodybuilding
competition, called the HYPERplasia Challenge. The Challenge allows all
members of ABC regardless of age, sex, or goals to enter. Click
Here for more information and to sign up now. You have to be a
member of our forums to sign up for this. This is an easy, free
process, which will allow you to ask questions to the top scientific
minds in bodybuilding today. Click
Here to sign up now! The current Challenge will last from May 7th
- July 2nd. Good luck!
One important aspect of the challenge is that you must take caliper
measurements. So studying this article is a pre-requisite for anyone who
is considering entering the competition.
Using Body Fat Calipers
First, pick up the caliper using the thumb and forefinger of one hand
(see figure 2). With your free hand, grasp a fold of skin, again using
your thumb and forefinger, pull it away from the body, and slightly
shake it to separate the skin and fat from muscle tissue. Now, grasp the
pulled skin with the caliper, approximately 1/4-1/2 of an inch below the
thumb and forefinger holding the skin. Next, hold the caliper in that
position for 2-4 seconds, applying the complete force of the caliper.
This time limit is to avoid skin fold compression, which can skew the
results (Fleck, 1981; Plowman & Smith, 2003).
To assure the utmost reliability of your measurement, repeat this
procedure 2-3 times, and take the average score. If the scores greatly
deviate from one another, you may consider practicing this more, and
then recording your body fat percentage, once you are able to improve
your reliability.
Note that before you take the next measurement, you should rub the skin,
and wait for a few seconds, so that the fluid can return to the area. It
would also be a good idea to mark with a pencil where you took your
measurement, so you can replicate it at the exact spot.
For those taking professional caliper readings, it is advised to measure
30-50 individuals who vary in body fat percentage, and then compare your
measurements with an expert caliper measurer’s readings of the same
individuals, and calculate the reliability between the scores. Or, you
could compare your measurements to valid methods such as hydrostatic
weighing ((Fleck, 1981).
Lastly, you should always take your body fat percentage at the same time
of day, to assure the utmost validity. The morning is a great time, and
before any workouts.
Other Measuring
Techniques
The “gold standard” for body fat measurement is under water weighing
(Fleck, 1981; Plowman & Smith, 2003). But this method is highly
inconvenient. Calipers are typically more accessible to individuals.
Further, if taken correctly, calipers yield a high concurrent validity,
which is the degree to which the scores of the test are related to some
other valid criterion standard available at the same time (i.e.
hydrostatic weighing). In this context, body fat percentage as
determined by calipers typically matches hydrostatic weighing (under
water weighing) with an error of +-2-5% (Fleck, 1981; Plowman & Smith,
2003). Typically, calipers tend to underestimate body fat for obese
individuals, and overestimate body fat for lean individuals.
Accordingly, the most accurate measurement typically occurs in
moderately lean individuals (Fleck, 1981).
Skin Fold Measurement Sites
Many experts recommend 7 measurement sites (skin folds) as 3-point
measurements are not as accurate, and 9-point tests yield results highly
comparable to 7-point tests (Plowman & Smith, 2003). This is also what
is used for those competing in current and future HYPERplasia
challenges.
Note, when taking these measurements, the individual should be in a
relaxed position.
The 7 sites are as follows (see figure 2) (Fleck, 1981; Plowman & Smith,
2003):
1. Triceps – grasp a vertical fold of skin, on the posterior side of
your arm (your triceps) at the midline. The measurement should simply be
at the halfway mark between your shoulder and elbow.
2. Abdominal – Take another vertical skin fold one inch to the right of
the umbilical cord (belly button).
3. Chest – this time, take a diagonal fold, with the long axis of the
caliper directed towards the nipple of the chest. It should be measured
mid-way between the anterior axillary fold (underarm) and nipple.
4. Thigh – take a vertical measurement at about the midline of the
thigh; approximately half way the distance from the patella (knee cap)
to the hip.
5. Suprailiac (iliac crest) – take an oblique measurement slightly above
the hip bone, along the natural diagonal curve of the structure, where
the oblique muscle is.
6. Midaxillary – grasp a vertical fold of skin, directly under the arm
pit.
7. Subscapular – take an oblique measurement right below the inferior
(bottom) edge of the scapula (the shoulder blade).
Adapted from
Plowman
& Smith, 2003
Figure 2
Skin Fold Measurements
Bringing it all together
(calculating)
Once you have your skin fold numbers, you can plug in your measurements
into the following equations.
First, calculate your body density (Db) with the following equation
(Jackson & Pollock, 1985)
For men, use the following equation:
Db = 1.112 -
(.00043499) (sum of 7 skin folds) + (.00000055) (sum of seven skin folds
squared) - (.00028826) (age)
For females, use the following equation:
Db = 1.097 –
(.00046971) (sum of 7 skin folds) + (.00000056) (sum of seven skin folds
squared) – (.00012828) (age)
Once you have the body density, plug this into the following formula for
your body fat percentage (Siri, 1961):
Body fat %=[(4.95/Db) – 4.5] x 100
Examples
Suppose a 25 year old male, has 7 measurements, all 5 mm in girth. He
would simply plug this into the Db equation as such:
Db = 1.112 -
(.00043499) (35) + (.00000055) (352) - (.00028826) (25)
Db=1.090242601225
He would then plug in his body density into the body fat percentage
equation as such:
Body fat %= [(4.95/1.090242601225) – 4.5] x 100
Body fat %= 4.03 %
Finally, to calculate total lean body mass and fat mass, simply take
your body fat percentage, divide by 100 (in this case, that would add up
to .0403), and multiply it by your body weight to find out how much
total body fat you have. Then, subtract your total body fat, by your
body weight, to find how much lean body mass you have. Thus, if this man
weighed 200 pounds, he would have approximately 191.95 pounds of lean
body mass, and 8.05 pounds of fat.
Easy to Use
Calculator
Click here for an easy to use body fat calculator,
Body Fat Calculator.
Finding Calipers
Calipers are fairly easy to find. Various internet sites have them, as
well as local fitness stores. If you have any problems finding them,
feel free to ask in our online forums by clicking
Here.
Conclusion
Body fat caliper measurements are a great way to accurately monitor your
progress. Hopefully, this guide will make the process smooth and
effective for you.
If you have any questions, feel free to email me.
Keep it Hardcore,
Venom
Vice President of ABCbodybuilding.com
Venom@abcbodybuilding.com
References
Jackson, A.S. and M.L. Pollock (1985). Practical assessment of body
composition. Physician Sport Med 13:76-90.
Plowman, S. Smith, D. (2003). Exercise Physiology for Health Fitness,
and Performance. Second Addition. Benjamin Cummings. P.g 392-395
Siri, W. E. (1961). Body composition from fluid space and density. In J.
Brozek & A. Hanschel (Eds.), Techniques for measuring body composition
(pp. 223-244). Washington, DC: National Academy of Science.
Steven J. Fleck Ph.D.. (1981): Exercise Physiology Corner: Determination
of Body Fat Via Skinfold Measurements. National Strength Coaches
Association Journal: Vol. 3, No. 5, pp. 56–60.
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