Near-Infrared Light Technology to Estimate Total Fat
Single Site measurement
The use of near-infrared light interactance to determine body composition was first investigated by Conway, Noms, and Bodwell in a study funded by the United States Department of Agriculture in 1984. The results of the study, "A New Approach for the Estimation of Body Composition; Near-Infrared Light Interactance", were published in the American Journal of Clinical Nutrition. In the study, Conway, Norris, and Bodwell found that near-infrared spectral data from the biceps of the dominant arm alone resulted in correlation coefficients equal to underwater weighing (hydrostatic densitometry) values.
All organic materials (i.e. fat or protein) absorb light in unique portions of the spectrum. The FUTREX-5000 emits nearinfrared light at very precise frequencies (938nm. and 948nm.) into your body-frequencies at which your body fat absorb the light and your lean body mass reflect the light. In essence, we are measuring how much light is emitted from the light wand and how much light is reflected back into the light wand. This measurement provides an estimation of the distribution between your body fat and your lean body mass.
The measurement is taken at the mid-point of the dominant bicep. Years of research with the U. S.D.A. has shown that taking measurements at all of the anatomical sites that are recommended with skinfold calipers will not significantly improve the accuracy of the technology. Eventhough men carry most of their body fat in their abdomen area and women carry most of their fat in their thigh region, measurements taken solely in these regions would significantly over-estimate total body fatness because they tend to be the highest concentrations of fat in the body and therefore are not representative of the entire body. As body fat is gained or lost, the distribution of fat/lean mass will change at the midpoint of the bicep based on the premise that you can not gain or lose fat in site specific areas-fat is gained or lost throughout the body.
Since 1984, there has been an abundance of research supporting the USDA's findings. infrared measurements from the biceps have been the primary site shown to correlate best with a criterion method (Conway and Norris, 1986, Elia et. al., 1990; Gullstrand). Possible reasons are best explained as Gullstrand hypothesized, "The bicep site was most representative of whole body fat"; or as conway and Norris hypothesized, "The combination of skin thickness and subcutaneous fat thickness at the bicens allows for optimal penetration and interactance of the low level of infrared radiation".
Additional research conducted by Sawai, 1988; Dotson and Davis, 1989; Cook 1990 McLean and Skinner, 1991; Heyward, 1992 concluded that Futrex's patented near-infrared technology, by itself (with no other variables) has been demonstrated to correlate significantly with body density, at the biceps site alone.
REFERENCES
Conway JM, Noms KH Bodwell CE. A New Approach for the Estimation of Body Composition: Infrared Interactance Am. J. Clin. Nutr., 1984; 40: 1123-1130
Heyward VH Jenkens KA, Cook KL et. al. Am. J. Human Biology., 1992; 4: 1123-1130
Sawai S., Shirayama M., Mutoh Y., Miyashita M Jpn. J. Phys. Fitness Sports Medicine., 1990; 39: 155-163
Ellis KJ, Yasurma S., Morgan WD. Energy and Protein Nutrition Laboratory and Instrumentation Research Laboratory. USDA/ARS, Beltsville, MD, 20705, USA(163-170).
Elia M Parkinson SA, Diaz E., (1990). Evaluation of Near-Infrared Interactance as a Method for Predicting Body Composition. European J. Clinical Nutrition, 44: 113 - 121.
McLean K., Skinner J. (1991). Validity of FUTREX-5000 for Body Composition Determination. medicine and Science in Sports and Exercise, 23 (4) S149(From abstracts 1991,23(4) Abstract No. 894.
Dotson and Davis (1989). NIR Evaluation for Body Composition (Abstract). Medicine and Science in Sports and Exercise 20:58,1988.
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