RESUMEN
To evaluate changes achieved in whole-body and regional (upper limbs, lower limbs, and trunk) estimates of body composition, twenty professional male soccer players (7 defenders, 7 midfielders, 6 forwards) underwent dual-energy x-ray absorptiometry (DXA) analysis at the beginning and end of pre-season. Measures included: mass, fat mass (FM), fat-free mass (FFM), and body fat per cent (BF%). Players' activity during on-field training sessions was monitored using Global Positioning System (GPS) units, with GPS data used to obtain estimations of energy expenditure (EE). Whole-body mass remained unchanged across the pre-season. Moderate significant increases and decreases were achieved in whole-body FFM (Pre: 59.58⯱â¯5.27â¯kg; Post: 60.61⯱â¯5.18â¯kg; pâ¯=â¯0.001; dâ¯=â¯0.87) and FM (Pre: 10.60⯱â¯1.88â¯kg; Post: 9.56⯱â¯1.81â¯kg; pâ¯=â¯0.001; dâ¯=â¯0.85), respectively. Moderate significant decreases were achieved in whole-body BF% (Pre: 14.4⯱â¯2.3%; Post: 12.9⯱â¯2.0%; pâ¯<â¯0.001; dâ¯=â¯0.94). No significant inter-positional differences were observed for the changes achieved in any global or regional estimate of body composition. Total EE was significantly correlated with ΔFM (râ¯=â¯0.65, pâ¯=â¯0.002), ΔFFM (râ¯=â¯0.46, pâ¯=â¯0.03), and ΔBF% (râ¯=â¯0.67, pâ¯=â¯0.002). The total EE of pre-season training accounted for 42%, 21%, and 45% of the variance in ΔFM, ΔFFM, and ΔBF%, respectively. These findings suggest that the pre-season period is a suitable time for initiating favourable alterations in body composition following the off-season in elite soccer players.