Reliability and validity of body composition measures in female
athletes.
Fornetti, Willa C., James M. Pivarnik#, Jeanne M. Foley and Justus J.
Fiechtner.
Departments of Kinesiology* and Osteopathic Surgical Specialties#,
Michigan State University; East Lansing, MI 48824
APStracts 6:0250A, 1999.
The purpose of this investigation was to determine the reliability and
validity of bioelectrical impedance (BIA) and near infrared
interactance (NIR) for estimating body composition in female
athletes. Dual energy x-ray absorptiometry (DXA) was used as the
criterion measure for fat free mass (FFM). Studies were performed on
132 athletes (M+/-SD; age =20.4+/-1.5 yr). Intraclass reliabilities
(repeat and single trial) were 0.987-0.997 for BIA (resistance and
reactance) and 0.957-0.980 for NIR (optical densities). Validity of
BIA and NIR was assessed by double cross validation. Because
correlations were high (r=0.969-0.983), and prediction errors low, a
single equation was developed using all 132 subjects for both BIA and
NIR. Also, an equation was developed on all subjects using height and
weight only. Results from DXA analysis showed FFM =49.5+/-6.0 kg
which corresponded to % body fat (% BF) of 20.4+/-3.1%. BIA predicted
FFM at 49.4+/-5.9 kg (r=0.981, SEE=1.1) and NIR prediction was
49.5+/-5.8 kg (r=0.975, SEE=1.2). Height and weight alone predicted
FFM at 49.4+/-5.7 kg (r=0.961, SEE=1.6). When converted to % BF,
prediction errors were [sim]1.8% for BIA and NIR and 2.9% for height
and weight. Results showed BIA and NIR to be extremely reliable and
valid techniques for estimating body composition in college-aged,
female athletes.
Received 23 September 1998; accepted in final form 26 May 1999.
APS Manuscript Number A849-8.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 14 June 1999