The potential use of Near-IR interactance for determining body composition was first investigated by Conway, Norris, and Bodwell1 in a study funded by the U.S. Department of Agriculture. Their study used a computer-controlled research spectrophotometer to correlate Near-IR interactance (NIR) measurements with hydrostatic weighing and skinfold thicknesses. Recently, a moderately priced Near-IR instrument was introduced: the FUTREX-5000™ (Manufacturer: Futrex, Inc., Gaithersburg, Maryland). This instrument uses interactance technology similar to that of Conway et al. The Human Performance Center (HPC), Alexandria, Virginia has performed a preliminary evaluation of the FUTREX-5000™. This initial evaluation included more than eighty subjects, covering a wide range of percent fat levels, gender and racial origins. At the Human Performance Center, each subject’s body composition was determined by 1) hydrostatic (densiometric) weighing technique following the protocols as described by Katch2, determination of residual volume as described by Goldman and Buskirk3 and calculation of percent body fat through the formula developed by Siri4 2) by multiple site skinfold measurements following the protocol of Jackson and Pollock5 3) by anthropometric measurements as developed by Davis and Dotson6 4) and by the FUTREX-5000™ Near-IR measurement. For the Near-IR measurements, the same multiple body sites were measured as for the skinfold measurements. This Technical Note summarizes the initial test data. Specifically, it discusses the relationship of single site Near-IR measurement (on the prominent bicep) with hydrostatic weighing and describes the test, re-test reliability of the instrument. The results of the full technical study will be published in the scientific literature.

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