Underwater Weighing Familiarization Program for Adults with Prader-Willi Syndrome.

The purpose of the project was to evaluate an underwater weighing (UWW) and residual lung volume (RV) familiarization program developed for adults with Prader-Willi syndrome (PWS). UWW was conducted on 15 adults (10 men, 5 women) with PWS following a UWW familiarization program. Repeated measures ANOVA revealed no difference in percent body fat derived from UWW over the four sessions, F(3, 27) = 0.80, p = .505, with an intraclass reliability coefficient of R = .93. There was, however, a significant difference in RV, F(3, 27) = 5.25, p = .006, with an intraclass reliability coefficient of R = .65. The familiarization program is recommended for implementation prior to measuring percent body fat via UWW. However, predicting the RV may be an easier and more consistent alternative to measuring the RV in adults with PWS.