Agreement between Body Composition Estimates using a 2D Imaging System Across different Body Positions and Days

Relative adiposity (%Fat) was measured using a smartphone-based application in a convenience sample of adults aged 20-52 years (n = 32, 68.7% female, 84.3% White/Caucasian, 26.7 +/- 3.5 kg/m(2)) across different body positions (Anterior versus Posterior) on consecutive days (Day 1 versus Day 2). A reference photo was obtained from the posterior view on Day 1 (POSTDay1), with an additional photo obtained from the anterior view (ANT(Day1)). A third photo from the posterior view was obtained on Day 2 (POSTDay2). Potential differences were assessed using an adjusted alpha level (p < .025). ANT(Day1) (26.44 +/- 6.19%Fat) was not different than POSTDay1 (26.84 +/- 6.07%Fat, MAPE = 3.63%, p = .04) (ICC = 0.99, SEE = 1.1%Fat, p < .001). In addition, POSTDay2 (26.65 +/- 6.17%Fat) was not different than POSTDay1 (MAPE = 3.30%, p = .31) (ICC = 0.99, SEE = 1.0%Fat, p < .001). Both ANT(Day1) and POSTDay2 were considered equal to POSTDay1, suggesting %Fat can be consistently measured from a single digital image using a smartphone-based application in healthy young and middle-aged adults.