Female pinching left suprailiac skinfold

The Fitties Blog

How to Calculate Body Fat with the Jackson-Pollock 7 Body Fat Formula

January 15, 2023 | Lifestyle and Wellness

Developed in 1978 by Dr. Andrew Jackson and M. L. Pollock, researchers and scholars in human movement, the Jackson-Pollock 7-spot body fat test incorporates some aspects of their famous Jackson-Pollock 3 and Jackson-Pollock 4 methods. The more comprehensive Jackson-Pollock 7-spot method further expands upon the 3- and 4-spot methods, thanks to the extra sites utilized in test calculations.

As with all of their methods, Dr. Andrew Jackson and M. L. Pollock sought to create a simple system for measuring an individual’s body fat. With their extensive backgrounds in health and fitness, the team incorporated their knowledge into developing simple mathematical equations that take various skinfold measurements into consideration. Their ultimate goal was to build a universal way of accurately determining a person’s body fat percentage based on skin thickness, age and gender.

The most simple forms of the Jackson-Pollock equations can be seen in the Jackson-Pollock 3 and Jackson-Pollock 4 body fat tests. These two methods are the easiest to perform because their calculations incorporate only three and four skinfold sites, respectively. However, Jackson and Pollock noted that with the simplicity of their 3- and 4-spot body fat formulas, there would be a higher probability for human error, as is the case with any scientific manner of research. As a result, body fat results from the Jackson-Pollock methods might not be as accurate when compared to more elaborate testing methods.

To limit the potential for human error, Dr. Jackson and Pollock created the Jackson-Pollock 7-spot body fat test. As the name suggests, this test utilities seven skinfold test sites across the human body. The locations of these test sites are the same for both males and females. Theoretically, the greater number of  body fat test sites allow for increased accuracy in determining the estimated body fat of an individual. Although there are a few more body fat test sites when compared to the 3- and 4-spot methods, the 7-spot method is still incredibly simple, convenient and easy to complete. This is especially true when it comes to comparing the Jackson-Pollock methods to advanced methods of analyzing body fat.

To improve the accuracy of the Jackson-Pollock 7-site body fat test, or any skinfold-based body fat calculation for that matter, experts often recommended that skinfold measurements all be acquired from the same side of the body (e.g. the right side of the body). For ever greater accuracy, experts also recommend that a minimum of two measurements be taken at each skinfold location. And if there is a difference of more than two millimeters between same-site measurements, then a third measurement is recommended. Then, when factoring into the body fat equation, the average of the same-site caliper measurements should be used.

If you need help with measuring body fat with calipers, be sure to check out our guide.

Jackson-Pollock 7 Skinfold Locations for Males and Females

  • Chest: The chest (pectoral) measurement is located between the nipple and the armpit. The chest skinfold pinch should be 1/3 of the way closer to the armpit and in a diagonal line that parallels the direction of the nipple-armpit line.
  • Midaxillary: The midaxiliary location is the horizontal or vertical skinfold on the side of the torso at the fifth rib. To determine the ideal positioning, locate the lower tip of the breastbone and follow a horizontal line along the side of the torso, stopping directly below the armpit. The arm should be raised to chest height when acquiring the measurement at the midaxillary location.
  • Tricep: The tricep measurement is a vertical skinfold that is acquired halfway between the top portion of the shoulder and the elbow.
  • Subscapular: The subscapular site is located at the bottom tip of the shoulder blade. Acquire the skinfold measurement at a 45 degree angle, approximately two centimeters below the bottom tip of the shoulder blade. This orientation should be almost be parallel to the inside angle of the shoulder blade itself.
  • Abdominal: For the abdominal measurement, take a horizontal or vertical skinfold that is one inch to the right of the belly button. A horizontal fold of skin might be easier to acquire for some people, however, the vertical skinfold tends to be used most often. With this in mind, the direction that offers the most comfort for the individual should be the one that is used.
  • Suprailiac: For the suprailiac measurement, locate the anterior (front) part of the axilla (armpit). Then, follow a vertical line down toward the hip until the hipbone is reached. The skinfold at this location should be at a 45-degree angle, going up and away from the body, approximately two inches above the iliac crest, otherwise known as the area above the upper and forward protrusion of the hip bone. Specifically, the skinfold is located between the top portion of the hipbone on the side of the body and the bony portion of the same hipbone along the lower right of the body.
  • Thigh: The thigh (quadriceps) measurement is located along the anterior (front) portion the quadriceps muscle, halfway between the upper part of the knee and the fold at the top of the thigh. A vertical skinfold for this measurement is ideal, however, skin and fat tend to be more firm in this area of the body, so a sturdy pinch may be required. With this in mind, there is a possibility of this location overestimating body fat content. Fortunately, with the additional skinfold measurement required for the Jackson-Pollock 7-spot body fat test, the overall accuracy should be fairly reliable.

Jackson-Pollock 7 Body Fat Formula for Males

If you would like to calculate body fat using the Jackson-Pollock 7-spot method, and your test subject is a male, use the formula below.

Measure the following skinfolds (in millimeters) with body fat calipers:
Chest
AxilaTricepSubscapularAbdominalSuprailiac and Thigh

Body Density = 1.112 – (0.00043499 x sum of skinfolds) + (0.00000055 x square of the sum of skinfold sites) – (0.00028826 x age)

Body Fat Percentage (%) = (495 / Body Density) – 450

Jackson-Pollock 7 Body Fat Formula for Females

If you would like to calculate body fat using the Jackson-Pollock 7-spot method, and your test subject is a female, use the formula below.

Measure the following skinfolds (in millimeters) with body fat calipers:
Chest
AxilaTricepSubscapularAbdominalSuprailiac and Thigh

Body Density = 1.097 – (0.00046971 x sum of skinfolds) + (0.00000056 x square of the sum of skinfold sites) – (0.00012828 x age)

Body Fat Percentage (%) =  (495 / Body Density) – 450

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