Mark Small

Document Type

Thesis - University Access Only

Award Date

2005

Degree Name

Master of Science (MS)

Department / School

Health, Physical Education, and Recreation

Abstract

Since the mid 1990' s, air-displacement plethysmograph (ADP) has been researched and proposed to be an accurate, comfortable, and accessible method of body composition analysis. It continues to be compared to hydrostatic weighing (HW), the anthropometric "gold standard" for validity and reliability. This study was designed to investigate the effects of dehydration on the measurement of percent fat (%fat), fat mass (FM), and fat free mass (FFM) as measured by bioelectrical impedance (BIA), air displacement plethysmograph (ADP), and hydrostatic weighing (HW). The sample consisted of healthy men (n = 13) and women (n = 13). Percent fat was measured by BIA, ADP, and HW before and after an exercise protocol designed to cause the participants to lose 2-3% of their body weight through exercise induced dehydration. In the present study, baseline measurements of Fat(% and kg) and FFM (kg) were different among the three methods of measurement, including Dt, between ADP and HW. However, the change in body composition variables Fat(% and kg) and FFM (kg) were not different between methods. Air displacement plethysmography and HW was only able to detect a change in FFM despite their ability to detect a change in body volume and weight in water respectively pre to post exercise. However, BIA was able to detect a change in impedance, Fat (% and kg), FFM (kg). There was a correlation between the change in plasma volume and the change in weight only (r-0.71, p=0.006). Urinary specific gravity was not correlated to any body composition variable. The change in weight was only correlated to the change in FFM by the BIA method (r-0.43, p=0.02). Air displacement plethysmography has been found to be an accurate method for estimating body composition in healthy adults in other studies. In the present study ADP and HW were unable to detect a significant change in body composition due to exercise induced dehydration of 2-3% body weight but BIA was able to detect a significant change in %BF, Fat (kg), FFM (kg). Further research needs to investigate dehydration and its' effects on the fluid spaces and how these effects affect the estimation of body composition with the current methods used in research today. Continuing studies should further assess the cause of the individual variations with this relatively new method.

Library of Congress Subject Headings

Body composition -- Measurement

Plethysmography

Impedance, Bioelectric

Dehydration (Physiology)

Format

application/pdf

Number of Pages

67

Publisher

South Dakota State University

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