The tester was reported as a potential source of variability in air displacement plethysmography (ADP). This work evaluates the impact of the tester on body fat percentage (%BF) assessments via ADP using the BOD POD system. We analyzed sets of consecutive ADP trials conducted on the same subject. A pair of randomly assigned testers performed 5 sets of 12 trials. Sets differed in subject preparation (eating, drinking, and bathroom visits). The results were analyzed using the Bland-Altman method, curve fitting, and the two-sample t-test. In a second protocol, a team of 6 testers performed 10 measurements each, in random order, and the mean values of their readings were compared via one-way analysis of variance (ANOVA). The two-sample t-test indicated no significant difference between the mean values of %BF recorded by the two testers who conducted the first protocol (P = 0.51). Moreover, intra- and intertester Bland-Altman plots were similar. The mean values of the readings of 6 testers differed by less than 0.46 %BF. According to one-way ANOVA, these differences were not significant (P = 0.33). The influence of the tester on ADP results is statistically insignificant and smaller than the technical error of measurement of the BOD POD.

Key words: Body composition, body fat percentage, body volume, resting metabolic rate, total energy expenditure.

Corresponding author’s e-mail: neagu.monica@umft.ro