There are a variety of different ways of combining weight and height to estimate body fatness, but the most common is to divide the weight and in kilograms, by the height in meters multiplied by itself. This is called the body mass index or BMI. The body mass index is a simple but adequate andthropometric index of adult nutritional status for use in populations. On the scale, people with an index over 25 and less than 30 are said to be overweight, and people with an index over 30 are defined as obese (Speakman, 2001). Researchers found a 5% increase in the risk of heart risk of heart failure for men and a 7% increase for women for each BMI in

One of the disadvantages to using this technique is the fact that the facilities used to facilitate the equipment are very expensive to build and maintain and they are not readily available at all medical or training centers. The validity of this test has been questioned because of the fact that there are limitations of the cadaver studies that have provided the typical tissue densities. The variability of the volume component of the density value is a major problem with hydrostatic weighing. Error in body density up to 10% may result from estimating residual volume. This error may result in an overestimating of the residual lung volume rather than predicating it from regression equations or from a certain percentage of residual capacity. The reliability of this test is very high but it may vary with the experience and control of the participant.

Underwater weighing is considered the most reliable method of measuring fat and lean body tissue in a clinical setting. The basis of hydrostatic or underwater weighing, technique is Archimedes’ principle. Archimedes’ priniciple states that the volume of an object submerged in water equals the volume of water the object displaced. Fat tissue is less dense and lean tissue is more dense than water, therefore, fat will float and fat-free tissue will sink. This technique, based on the relative densities of fat and lean tissue, makes use of an individuals weight in air and in water. When determining body density with this technique, the mass is commensurate with the weight of the body out of the water. The volume of the body is determined by calculating the difference in body weight when weighed underwater, corrected for the density of water. This method it is necessary that the calculations also be corrected for the buoyancy of the air trapped in the lungs and the gastrointestinal tract during submersion. Th

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