Body Composition Changes In National Basketball Association Players Using Dual-energy X-ray Absorptiometry

Body composition assessment is commonly performed in many settings in competitive sports, including the National Basketball Association (NBA), but published studies are very rare. Furthermore, many NBA players are too tall to fully fit on the gold-standard Dual-energy X-ray Absorptiometry (DXA) tables. PURPOSE: This study 1) aimed to describe a novel DXA scan analysis technique for athletes exceeding the table dimensions using custom region of interests (ROI); 2) using this method, report within and between season body composition changes in NBA players. METHODS: DXA scans from one NBA team between 2013 to 2022 were analyzed. First, for participants exceeding the DXA height limit (192 cm) all scans were measured from the top of the head to the end of the scan area and the shortest height was identified for each individual. Using this height, a ROI was then applied to all scans from that player, ensuring the analyzed area of the player was consistent in each scan. We then compared bone (BMC), bone-free lean body mass (LM), fat mass (FM), and LM:FM within and between seasons. One-way and Repeated Measures ANOVAs with Least Significant Differences post hoc analyses were used, α = 0.05. RESULTS: 441 DXA scans from 73 NBA players were analyzed. The ROI method was used for 66 of these participants, resulting in an average loss of 10.9 ± 6.4 cm and 6.5 ± 1.8 kg. Younger players had significantly reduced BMC and LM (Figure 1 - top and middle panels) compared to older players 26+ y/o (all post hoc p ≤ 0.037). For the whole group, within season improvements in LM:FM before and after the All-Star Break were found Figure 1 - bottom panel; both post hoc p ≤ 0.036). However, these data are most likely driven by significant reductions in FM mid-season for players >23 y/o (both post hoc p ≤ 0.012) but not younger players who maintained their FM within seasons (all p ≥ 0.173). CONCLUSION: This study shows with increasing age, bone and muscle mass increase, as does the variability of fat mass within seasons.