Three-dimensional (3D) infrared scanners, which estimate total body mass (TBM), fat mass (FM), lean mass (LM), and body fat percentage (BF%) via measurements of circumference, are gaining popularity for their portability, affordability, and visibility compared with dual energy absorptiometry (DXA) scans. Critical comparisons between the two measurement techniques, particularly regarding longitudinal changes, remain limited. PURPOSE: To compare longitudinal (pre-to-post) changes in TBM, FM, LM, and BF% using both 3D-infrared and DXA scanners. METHODS: 37 (27 male; 10 female) NCAA D2 athletes participated in both pre-and post-season total body composition measurements using a 3D infrared (NAKED™) and DXA (Hologic Horizon A) scanner, performed within five minutes of each other. Paired t-tests were used to compare LM, FM, and BF%, with longitudinal changes defined mathematically as the post-season minus pre-season values (mean diff.). Correlations between DXA vs. NAKED scans were evaluated using Pearson's r. Estimated effects size used Cohen's d. RESULTS: Mean diff. (NAKED™ -DXA) in LM were significantly higher using the infrared scan (4.57±5.06, p<0.001,d=0.90) compared to DXA, with a significant, but weak correlation (r=0.412,p=0.011). No significant differences were found between TBM (0.13±0.77, p=0.29,d=0.18), FM (0.43±4.33, p=0.55,d=0.10), or BF% (-0.49±2.03, p=0.15,d=0.24) mean diff., but all were significantly correlated between the two devices (TBM: r=0.953, p<0.001; FM: r=0.655, p<0.001; BF%: r=0.347, p=0.35). CONCLUSION: Compared with the DXA scan, the NAKED™ scanner showed no significant differences in measuring changes from preto post-season in TBM, FM, and BF%. However, LM change was significantly higher in the NAKED™ scanner. Therefore, the NAKED™ scanner could be a used as surrogate method for assessing changes in TBM, LM, and BF%. However, because of the discrepancies in LM changes, caution is recommended until algorithms to improve agreement between the DXA and NAKED scans are addressed.
