Date of Award

December 2012

Degree Type

Thesis

Degree Name

Master of Science

Department

Kinesiology

First Advisor

Ann M. Swartz

Committee Members

Lori A. Klos, Susan Cashin

Keywords

Assessment, Bioelectrical Impedance Analysis, Body Composition, Body Fat, Hand-Held BIA

Abstract

Because of health concerns surrounding overweight and obesity, many individuals, health clubs, and physicians have begun using portable measures of body fat (BF) that are inexpensive and easy-to-use. Based on measures from these devices, health-related decisions are made and progress during fitness and/or dietary programs is tracked. However, accuracy of portable BF devices can be questionable, especially in free-living settings. Purpose: The purpose of this study is to evaluate the validity and reliability of a commercially-available, hand-held bioelectrical impedance analysis (BIA) device as a measure of BF during a controlled laboratory condition and a free-living condition. Methods: A total of 91 White individuals (41 men, 50 women), ages 19-39 (young group) and 55-75 years (old group), completed the study. During the laboratory visit, body fat measures from the hand-held BIA and to two additional methods, DEXA and tetrapolar BIA, were compared across age and sex when pre-testing guidelines were followed. Participants were then asked to take the hand-held BIA home to complete four free-living BF% measures. A mixed between by within design comparing sex and age groups (between groups variables) across hand-held BIA, tetrapolar BIA and DEXA measurements (within groups variable) was performed to determine whether differences among body fat assessment devices exist. Post-hoc planned comparisons were performed to determine which devices are different in assessing BF among the hand-held BIA, the tetrapolar BIA and the DEXA. Repeated-measures ANOVA with post hoc comparisons were performed to determine differences in BF measures among hand-held BF measures over the free-living day. Results: BF results from the hand-held BIA were significant from DEXA and tetrapolar BIA for the female and young groups. Specifically in the female group, the hand-held BIA underestimated %BF by 2.7 percentage points compared to the DEXA. The tetrapolar BIA also underestimated %BF by 2.5 percentage points compared to the DEXA. In the young group, the hand-held BIA underestimated %BF by 3.5 percentage points compared to the DEXA. The tetrapolar BIA also underestimated %BF by 3.8 percentage points compared to the DEXA. In the male and old groups, there was no significant difference between BF measures from DEXA and hand-held BIA, but significant differences were present between the tetrapolar BIA and hand-held BIA. The hand-held BIA overestimated %BF by 2.6 and 1.9 percentage points in the male and old groups, respectively, as compared to the tetrapolar BIA. Despite the fact that there were statistically significant differences in BF measures from the hand-held BIA and the DEXA, these differences did not exceed the clinically acceptable level (±3.5%). Conclusion: The hand-held BIA device is designed for use by individuals to assess BF level. Although means were not clinically different between the hand-held device and DEXA in all groups, difference scores between devices suggest that the hand-held BIA is not a valid device on an individual level and, therefore, not recommended for the assessment of %BF.

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