Body composition and bone mineral density changes during a premier league season as measured by dual-energy X-ray absorptiometry

Body composition was repeatedly assessed in 28 male Premier League football players using dual energy X ray absorptiometry (DXA) [UK; date not given]. Assessments were performed at the beginning (T1) and end (T2) of 6 weeks of pre-season training, 29 weeks later during the competitive phase (T3) and at the beginning (T4) and end (T5) of a 6-week pre-season training phase the following year. Total mass, body fat per cent, and fat mass decreased (P<0.05) during the pre-season phase of the first year (T1-T2); body fat per cent and fat mass decreased (P<0.05) and fat-free soft tissue mass increased significantly (P<0.05) during the same phase of the following year (T4-T5). Total mass, body fat percent and fat mass increased (P<0.05) between the end of the pre-season (T2) and the middle of the competitive season (T3). Total body mass, body fat percent and fat mass were not significantly different mid-way through the competitive phase from the beginning of the pre-season phase (T1-T3; P>0.05). There were no further changes in total mass, body fat percent, fat mass or lean mass between the middle (T3) of the competitive season and the next measurements (T4; P>0.05). Values were not different at the beginning of the second year of pre-season training (T4) than they were at the beginning of the first year (T1; P>0.05). Body composition changes reflected seasonal shifts in emphasis of training. Positive changes in body composition observed pre-season were lost by the middle of the competitive season, but were restored in the subsequent start of pre-season training.