Changes in markers of body composition of professional male soccer players during pre-season

Abstract 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 ± 5.27 kg; Post: 60.61 ± 5.18 kg; p = 0.001; d = 0.87) and FM (Pre: 10.60 ± 1.88 kg; Post: 9.56 ± 1.81 kg; p = 0.001; d = 0.85), respectively. Moderate significant decreases were achieved in whole-body BF% (Pre: 14.4 ± 2.3%; Post: 12.9 ± 2.0%; p