Author and graduation date: Steve PETTIS, April, 2001

Committee members: Patricia Patterson (Chair), Denise Wiksten, Jesse Dixon

Thesis title: Reliability of the Futrex 5000 (Near-infrared Interactance) to Determine Percent Body Fat (%BF) and Amount of Training Needed for Accurate Use of the Futrex 5000

The purpose of this study was 1) to determine the internal consistency and test-retest reliability of NIR (Futrex 5000 -- near-infrared interactance) for testing %BF in male high school athletes; and 2) to determine the intertester reliability of two equally trained testers. Fifty-one male students between the ages of 14 and 18 were recruited from high school football teams (freshman, junior varsity, and varsity) at Ramona High School. The body fat testing was administered over a period of a week with each student tested on two separate days. Body composition was tested by measuring the biceps halfway between the armpit and the elbow at the "belly" of the biceps muscle. Reliability (and 95% confidence intervals) of each tester was examined within each day of testing and across days using an intraclass correlation coefficient derived from one-way analysis of variance (ANOVA). One-way ANOVA with repeated measures was used to determine whether there were significant differences between trials or across days. Intertester objectivity was also examined for each day using an intraclass correlation coefficient. Single trial reliability was R = .99 (CI = .98 to .99) between trials on both days for both testers. Intertester reliability was R = .99 (CI = .99 to .99) across both trials on both days. These results suggest that this is a reliable testing method; the logical next step is to test the validity of the NIR method with this population. It would also be valuable to know if testing greater numbers of subjects during a single testing session will affect reliability.

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