Skinfold methods

In this method the tester pinches the skin at the specific site to raise a double layer of skin and the underlying fat, but not the muscle. Special calipers are then used to measure the skinfold thickness. Formulas convert these numbers into an estimate of a person's percentage of body fat according to a person's age and gender.

Calipers only measure fat under the skin. Two individuals might have the same skinfold measurements, but their fat levels in the abdominal cavity may be very different.

Unfortunately there is no simple and affordable way to accurately measure the body fat percentage. This can be done, but you will need to undergo a number of exotic and expensive procedures: measure your bone density with dual energy X-ray absorptiometry, then measure your body water using the dilution principle with isotopically labeled water, finally find out your exact body volume and density with underwater weighing, and feed these numbers to a special formula.

If you want to monitor your own progress, the skinfold method is accessible, more reliable than "body fat scales" (Bioelectrical impedance method), and more accurate than the US Navy method.

With GymGoal you can monitor both the estimated body fat percentage and individual skinfolds measurements.

Consistency

Skinfold measurements are sensitive to the type of caliper used, and technique. They should be done by the same person, with the same technique and the same caliper.

To be accurate body fat calipers need to exert a certain amount of constant pressure (10 gm./sq. mm). Bad quality calipers lack tension control and won't stay accurate for very long.

Procedures

• All measurements should be made on the right side of the body with the subject standing upright.
• The caliper should be placed directly on the skin surface, 1-2 cm away from the thumb and finger, perpendicular to the skinfold, and halfway between the crest and the base of the fold.
• A pinch should be maintained while reading the caliper. Wait 1 to 2 seconds (not longer) before reading caliper.
• Take duplicate measures at each site, and retest if duplicate measurements are not within 1 to 2 mm.
• Rotate through measurement sites, or allow time for skin to regain normal texture and thickness.

Correct position of caliper jaws

Incorrect position of caliper jaws (not perpendicular to the fold and not across a double thickness.)

Skinfold sites

Body fat estimation formulas use from 3 to 7 different standard skinfold sites around the body. A formula with more sites will not always give you more accurate result - it all depends on your body fat distribution, large portion of which may be in your abdominal cavity.

Select one formula and use only it to monitor your progres. You may want to chose the formula that measures skinfolds in areas that you want to monitor the most. Other than that, the most important thing in measurements is consistency. Select skinfold sites that you can locate consistently. You need to measure always exactly the same spot.