Publication Date



Open access

Embargo Period


Degree Name

Master of Science (MS)


Kinesiology and Sport Sciences (Education)

Date of Defense


First Committee Member

Joseph F. Signorile

Second Committee Member

Arlette C. Perry

Third Committee Member

Tony Musto


Purpose. The bioelectric impedance analyzer (BIA) is a device commonly used to assess body composition; however, there are questions concerning the reliability of single- and multiple-frequency machines across multiple testing days and their relative accuracies. The purpose of the present study was to compare a single- versus multiple-frequency BIA results across two testing sessions and to compare results for each session to plethysmography as represented by the Bod Pod. Our hypotheses were that results for both BIA units would be consistent between testing days and no significant differences would be seen among the three testing methods. Methods. Twenty young adults (MEAN±SD, age 24.1±3.7 years) were randomly tested on the three devices to determine their reliability and validity. Results. Repeated measures ANOVA, Pearson correlations, Bland-Altman analyses and Chronbach’s alpha confirmed the consistencies of measurement between days for each BIA device and among the three body composition techniques. Conclusion. Single- and multiple-frequency BIA each provide reliable results across testing sessions and these devices and the Bod Pod can be expected to provide consistent results in healthy, young adults.


Body composition; Plethysmography; Bioelectrical Impedance Analyzer