As fitness professionals, we are often approached with the question of what is the best, most efficient way of analyzing body fat. There are only a few methods that are applicable in a gym setting: circumference measurement, electrical impedance, and skinfold analysis. Both circumference and electrical impedance have a larger percentage of error, so the blog will compare the accuracies of the Durnin-Womersley four-site skinfold and the Jackson-Pollock seven-site skinfold. While other methods for skinfold measurement exist, these are the two most commonly used.
For our research, we will use six individuals of varying gender, body size, age, and shape to compare the different methods. According to our anthropometric findings, the variation between the four and seven-site, is greatest in females and the largest differential occurs with age. The four-site has a larger fluctuation with older females and this is supposed to account for lower body density resulting in more visceral fat accumulation. Fifty to Seventy five percent of fat is subcutaneous, thus the difference in estimate between methods can only be proportional to the remaining body weight.
According to the American Journal of Clinical Nutrition, select skinfold equations can have a marked overestimation of body fatness. The Jackson-Pollock seven-site skinfold test is known to be more accurate because of the formulation, variation, and quantity of sites being used having a relatively low margin of error in comparison to hydrostatic weight of only 3.3% inaccuracy. A lot of individuals have differing shapes in the lower body region, and none are included in the Durnin-Womersley skinfold test, making it more reliant on estimation.
Regardless, periodic skinfold measurements will give a reflection of change despite the estimate of body fat percent. In other words, doing regular skinfold measurements will still show changes that are occurring.
If you would like to check body fat measurements or have further questions, please contact either Amber Gruger or Amber Walz.
There are many techniques to measuring the amount of fat one has on their body; some shown to be very accurate and others not so much. Below are NINE different ways professionals have come up with thus far to measure the amount of body fat on oneself:
Body Mass Index (BMI) – This is a calculation that simply uses the subject’s height and weight. These two numbers are put into a formula and calculated out to give you an estimated body fat percentage. This technique does not take muscle into affect, therefore if we have a male subject who is 5’6” and extremely muscular so he weighs 200lbs, the BMI calculation will say that he is in the obese category.
Bioelectrical Impedance Analysis (BIA) – This is a scale or handheld device that sends a harmless electrical current through your body to read your body fat. The strength and speed of the electrical signal is measured by this along with your age, gender, height and weight. These devices are very sensitive to hydration; therefore if you have consumed a large amount of water or even a bottle of water right before using the BIA, readings will be hindered.
Skinfold Calipers – This is a pinching test measured at different locations on your body with a device called Calipers. This test depends on the skill level of the person giving the test and how well they know exactly where and how to pinch the skin. The skin fold calipers measure the amount of subcutaneous fat, which is the fat found beneath the outermost layer of skin. It does not take visceral fat into account, which is found between the organs in the peritoneal cavity.
Dual Energy X-ray Absorpitometry (DEXA) – This is the same device specialist use to measure bone density to determine the risks of osteoporosis. This x-ray scanner can also measure your body fat mass as well as your muscle mass. Not only does it measure overall body fat, but it can pinpoint the fat deposits in specific areas of the body.
Infrared Light Measuring – This is a probe that is placed on the body and sends an infrared light ray through the fat and muscle content. It also takes your age, gender, height, weight, frame size, and activity level into account. The probe then gives you an estimated percent of body fat.
Hydro-densitometry (Under water weighing) – This is a tank device filled with water where the subject sits on a chair attached to a scale. They then blow out air and continue to blow out all their air while going under water. The person giving the test will read the scale once the subject has displaced as much air as possible. This number will be put into a calculation and give you a body fat percentage estimation.
Bod Pod – This is a chamber that you sit in while being very still and controlling your breathing. It relies totally on your air displacement to determine your body fat. Your hydration level before the test is one thing that can affect the results, along with movement and breathing technique.
Girth Measurements – This is done with a tape measure at different places on the body. The most common place and the one used for determining body fat is the waist. Waist circumference is taken at the belly button level. Men with a measurement higher than 40 inches and women with a measurement higher than 35 inches are considered obese.
Height/Weight Charts – This is a table or chart comparing weight versus height. Your height is on one axis and weight on the other, then bringing the two to meet in the middle, it determines if you are “underweight,” “average,” “overweight,” or “obese.” This takes gender into consideration, and does not put age or muscle versus fat into play.
I’m sure everyone is wondering which of these 9 techniques is considered the BEST and the WORST. More insight to this will be coming in a follow up to this post in the near future. If you have questions about your body fat measurements, please feel free to contact Personal Trainer Amber Gruger.