RELIABILITY OF AIR DISPLACEMENT PLETHYSMOGRAPHY

• Published in: Journal of strength and conditioning research Vol. 21; no. 1; pp. 169 - 172
• Main Author: ANDERSON, DAWN E.
• Format: Journal Article
• Language: English
• Published: United States National Strength and Conditioning Association 01.02.2007; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Adult; Air; Body Composition - physiology; Body Constitution - physiology; Confidence intervals; Female; Human body; Humans; Male; Plethysmography - instrumentation; Reproducibility of Results; Respiratory system; Sensitivity and Specificity; Testing
• ISSN: 1064-8011; 1533-4287
• DOI: 10.1519/00124278-200702000-00030

The purpose of this study was to examine the reliability of an air displacement plethysmography device (BOD POD) over trials performed on 3 different days. Subjects consisted of 24 healthy adults (8 men, 16 women), ages 18–38 years, with body weights 46.8–93.6 kg, body mass indexes of 19.1–30.1 kg·m, and percentage body fats (BF) of 7.9–43.1%. Two estimates of BF were performed on 3 days. Paired t-tests revealed no significant within-day differences in body volume (BV), thoracic gas volume (VTG), body density (BD), and BF. Correlations between the two VTG measures on a day were r = 0.86 for day 1, r = 0.93 for day 2, and r = 0.96 for day 3. BF estimates within a day had high correlations of r = 0.98. Significant differences were found between days for measures of BV, VTG, BD, and BF. These results indicate a high reliability for within-day estimates of BF and significant differences in between-day estimates of BF using air displacement plethysmography. Reliability of BF may be increased by requiring subjects to practice the procedure for VTG measurement.