The equations of fat

Sports are very concerned about their weight. But it does not mean much as long as one does not differ from that of fat muscles. How?

To understand the irrelevance of the only weight criterion for judging a template, just compare two 120 pounds to 1.80. One can be downright obese, the other pillar of rugby. The proportion of fat in fact varies from 5 to 50% of body weight in different individuals. Can be calculated precisely this distribution dissected after death. For live, it obviously makes less directly. The reference method is the hydrostatic weighing. It is based on the famous Archimedes principle: a body immersed in a liquid undergoes from one vertical thrust upwards equivalent to the weight of the displaced fluid. Weighed the person in the water, then, out of the water and its density is calculated according to the formula: density = 1 + weight water / weight out of the water. The result depends on the composition of the body. It is known that fat has a density (0.901 g / cm3) significantly lower than that of the muscle (1.10 g / cm3). Conversion tables then give body fat levels. This method nevertheless contains a number of errors. Recent studies indicate that indeed the density of lean body mass varies with age, sex, degree of shape and ethnicity. Finally, hydrostatic weighing is a last problem: the air contained in the lungs. The underwater weighing must be done after emptying air from the lungs in a tuba case. It also recommends to repeat the experiment several times during the same session.

The body fleet

Another technique, called hydrometric gives very close to the actual values ​​results. She is interested in the water content of the body. For this, we measure the hydrogen isotopes in biological fluids: saliva, urine, plasma. Concentration reflects the total amount of hydrogen in the body. This data is used to determine the proportion of fat to the extent that the adipose tissue is specifically devoid of any liquid. For a given weight, there will be even less of fat that can be water, and vice versa. A method that takes into account the permeability of the body to electromagnetic waves. It is commercially available devices that can perform this type of testing. The slightly different depending on the tissue allows conduction again to assess body fat with acceptable accuracy.

Body blowdry

Finally some experts are still based on the technique called adipose folds imagined by Brozek in 1963 and improved later by Jackson Pollock. It is based on a finding of a biblical simplicity. It is known that the fat is stored mainly in the skin, that is to say, in the dermis, a layer which can be easily pinched in evaluation purposes. Measuring instruments then give the thickness of the fold to the millimeter. Is repeated in different places of the body and it then uses extrapolation formulas to determine the total amount of fat in the body. The validity of the results, however, depends largely on the quality of the equipment and the experience of the user.

Syndrome triathlete

In conclusion, remember that these measures are useful at the individual level, to know where one is in the fight against overweight. If the methods are not available as is 100% reliable, there is no reason to make a cheese. Ultimately, we even see some danger to have too powerful tools. Sports have too often consider their fat as an unnecessary burden and correlating performance and weight. Call it the "syndrome triathlete." They come to forget some essential truths: first, that the proportion of fat depends largely on genetic factors. On the other hand, that fats are useful in many fields: hormone production, immunity, protection against cold and shock, energy intake, etc. Exclude all fat ?? and you will disappear with them.