Measuring Body Fat

Most bodybuilders are intimately familiar with body fat. The freakishly ripped and striated bodybuilders catch everyone’s attention. Low body fat is the goal of every competitive bodybuilder, and most casual trainers. So, to start, what is body fat?

What is Body Fat

Body fat takes on two forms. First is the essential fat. This is the fat and oils within the body that keep it functioning properly. Many of the organs are protected by a layer of this fat. The joints are lubricated by it and some is used in the body’s hormonal and messenger systems. The amount of essential fat varies between males and females, with females having more to support reproduction and other hormonal differences. The essential fat in males makes up 2-5% of total body composition and in females it is in the 10 to 13% range.

The second form is stored fat. This is the energy stores that are used in times of extreme starvation or prolonged exercise. This is also the muscle covering fat that most people fight with. Some of this fat is stored in cushioning positions and is helpful, but a large percentage is not healthy. Body fat percentages, as expressed in total percentage, is a total of both essential and stored fats. The recommended total body fat percentage for the average person is 20-25% for women and around 8-14% for men. Obesity is considered above 30% in women and above 25% in men. Of course, bodybuilders shoot for the lower end of the range or below.

Body Fat Measurement By BMI

There are many ways to measure body fat ranging from the simple, rather inaccurate body mass index to the more complex, expensive, but highly accurate, Dual energy x-ray absorptiometry. The body mass index (BMI) is not a true measure of body fat because it simply uses height and weight as variables. BMI is the least accurate for strength athletes and bodybuilders due to their large mass relative to their height. Similar to the BMI test, but slightly more athlete friendly, are the circumferential tests. Measurements are taken of various body circumferences and then they are put into a formula to reach a desired number. Again, these have a very low accuracy rating.

Body Fat Measurement By Skin Fold

Another convenient and inexpensive, although still having as much as a 10% variance rating, is the skin fold measurement. This method requires using calipers to measure folds of fat taken at various sites on the body. Some of the common sites include the triceps, hips, stomach and thigh. This method can be done very easily, and it can be done at home. Even if the accuracy may be low, it is great for tracking progress. For example, if the total sum of all the skinfold sites was 70 mm, then a goal of reducing that number allows for accurate tracking of progress.

Body Fat Measurement By Electrical Impedance

Impedance testing is another, more accurate, method. Electrical impedance is the lesser expensive of the two methods. It involves a low charge electrical impulse being passed through the body. The theory behind this test is that the electricity passes easier through the lean tissue. The higher the impedance, the higher the body fat percentage. A more expensive, and more accurate method of impedance testing involves the use of an infrared beam. The concept is the same but the infrared light is more accurate than the electrical impulse.

Body Fat Measurement By Hydrostatic Weighing

Hydrostatic weighing was the gold standard in body fat testing for a long time. It involves submerging the individual in water, after exhaling all the air in their lungs, and measuring the displacement, by comparing their weight in the water to that on dry land. This method requires an extensive list of equipment and technicians trained in the measurement methods. It is an expensive test and is labor intensive. It is, however, still a very accurate method of measuring body fat.

Body Fat Measurement By X-Rays

The new standard for body fat testing involves using two different types of x-rays to scan the body. It is called dual energy X-ray absorptiometry (DXA or DEXA.) One of the x-rays detects all body tissue and the other does not detect body fat and then the two images are scanned by a computer for the differences and the percentage is figured from that difference. There are other clinical tests that can be combined with this method to increase the accuracy to a variance of under 1%. However, the cost of this method makes it highly unlikely for the average bodybuilder.

Bodybuilders who live near a university may be able to get hydrostatic testing done, but for most bodybuilders the skinfold method of body fat testing is the most practical. The key to skinfold testing is to understand the limitations and use it as a tool, along with the scale and the mirror, to set goals and assess the progress toward those goals.

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