Chances are if you went through any type of fitness assessment at your health club between the years 1970-2000 you were probably subjected to skinfold calipers that measured your body fat.

There may be some version of this type of ancient science still going on somewhere out there today but read on to see the validity of these tests, given new advancements in the study of body composition.

Typically, someone you met just 5 minutes earlier would come along and pinch various parts of your body and apply something that looked like one-handed salad tongs purchased from the bargain bin at the local hardware store.

It didn’t hurt, if we don’t count your pride, and it looked sort of sciency so we gave it a go.

How accurate are calipers?


Now to be fair some of the better calipers were calibrated very precisely and delivered consistent results, if used properly, and they didn’t all look exactly like salad tongs.

But, the issue wasn’t really with the quality of the equipment or what it looked like, it was more about how they were used and the equations that were then applied to arrive at a body fat percentage. So, without further ado let’s dive into a comparison between the science behind Bio Electrical Impedance Analysis (BIA) and skinfold calipers.

How accurate are calipers?


To fully understand the original value of the calipers and how they were used to arrive at a % body fat you must also get to know their fat finding accomplices. Typically a tape measure and a weight scale were used to arrive at a BMI value and a waist to hip ratio.
The W/H ratio was an attempt to understand if additional weight carried in the stomach area was putting you at greater risk of disease or death (morbidity and mortality) and your height and weight was used to determine your Body Mass Index (your weight proportionate to your height).
For average populations or where there was no other access to more sophisticated testing these were adequate for the times because they didn’t involve any real measurement disparities between different people collecting the test results.

We now know that BMI alone doesn’t account for different fitness levels and were unjustly used in determining life insurance premiums based on BMI table norms for a population. An Olympic athlete or professional football player for instance could come out obese on the charts because of their greater muscle mass and average height and an out of shape but lower weight individual could come out looking healthy and ideal by virtue of their BodyMass Index score.

Problem with BMI


Yes they were convenient for their portability and relatively low cost, and in the right hands they did register changes in fat specific deposits over time. But, the positives end there.
  • Calipers needed to be applied to a consistent skinfold thickness, usually held for 3 seconds in order to allow the skin to compress properly.This was rarely done correctly.
  • The jaws of the calipers needed to be applied at a precise angle to the skinfold consistently.
  • The exact skinfold location could not just be eyeballed, it needed to be measured with a tape measure for accuracy.

The Jackson-Pollock Equation was the gold standard for the health/fitness assessment industry. It took what was assumed to be the normal effects of aging on a population and converted the skinfold reading into a percentage of body fat.

It didn’t however take into consideration that not everyone ages at the same rate. Two people of the same age that may have greatly different amounts of muscle mass and physical capacities were compared within the same groups. If calipers were still used today it would be with this same equation.

Science also knows a lot more now about visceral fat verses subcutaneous fat and their relationship to health.  The skinfold caliper equations don’t take that into consideration because there is no way of knowing the difference when taking a skinfold alone.


Every so often a paradigm shift happens in an industry. It might be because of a new way of thinking or a major scientific breakthrough or in the case of Evolt, both.

Evolt uses non-evasive BIA to produce a comprehensive report of body composition called a Bio Wellness Score and it does it all in only 60 seconds.


Scan your body in 60 secs


Much like Dr. McCoy from Star Trek with his medical body scanner, Evolt analyses a variety of body tissues including muscle mass, fat mass, total body water, mineral and bone content to present a complete picture which can then be viewed on your smart phone, computer or tablet. Unlike Star Trek however, this is the real deal and there is no tester error because of  TV make believe or imprecisely placed calipers or poor landmarking.

Bioelectrical impedance offers many advantages over older mechanically attained data from calipers. The 5-point algorithm, utilizing age, gender, height, weight and impedance uses only evidence-based data from over 40 different data points.  This means the highest standards of scientific integrity have been applied.  This alone eliminates the human testing error so inherent with typical health club testing using calipers.


Of particular note is the fitness age score (Bio Age Score). Imagine being told as a 50 year old man you have the body of a fit 35-year-old male or as a 30-year-old woman you have the fitness age of an older 45-year-old female. In both cases the incentive to either keep going or make some significant life changes is very much present.

Taken to the next level that same individual could receive a complete calorie and macronutrient profile along with recommendations based on their activity level goals,  target body weight and body composition.  Evolt does all that.

The advantage of an Evolt BIA scan doesn’t end here but the comparison to calipers does, because it’s really no contest.

body fat

Ask you health club manager about Evolt and if they look confused send him/her a link to our website or just have them read this article by Club 12RND Fitness and why they replaced calipers with Evolt.

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