Andrew Jenkinson

Limited data exist describing how professional footballers meet their energy requirements during pre-season, a phase characterised by increased training volume and a progressive shift from general conditioning to football-specific preparation. This study quantified total, resting, and activity energy expenditure (AEE), diet-induced thermogenesis, water turnover, and dietary intake in six professional male soccer players (age: 25 ± 1 year; height: 182.5 ± 10.1 cm; body mass: 77.8 ± 8.2 kg). Players were studied across 14 consecutive days, representing training-only and training-plus-match microcycles. Total energy expenditure (TEE) was measured using doubly labelled water, resting energy expenditure (REE) by indirect calorimetry and dietary intake using the remote food photography method. Fourteen-day mean TEE, REE, AEE and water turnover were 13.25 ± 1.31 MJ⋅day−1, 7.96 ± 0.89 MJ⋅day−1, 4.20 ± 1.03 MJ⋅day−1, 5.16 ± 0.66 L⋅day−1, respectively. Physical activity level was 1.67 ± 0.16 AU. Energy, carbohydrate, protein, and fat intakes were 10.95 ± 1.52 MJ⋅day−1, 2.8 ± 0.6 g⋅kg−1⋅day−1, 2.2 ± 0.4 g⋅kg−1⋅day−1, and 1.5 ± 0.4 g⋅kg−1⋅day−1, respectively. Total energy expenditure was not significantly different between training-only and training-plus-match microcycles (+1.89 ± 1.98 MJ⋅day−1; ES = 0.95 ± 1.08; p = 0.100). No significant differences were observed in energy or macronutrient intake across weekly microcycles (p > 0.068) or between days (p > 0.144). Players did not achieve energy balance or align dietary intake with day-to-day training demands, suggesting limited nutrition periodisation during pre-season. These findings highlight the need for practitioners to implement strategies supporting fuelling, recovery and adaptation during this critical phase.

Abstract

Body composition assessments in professional male football often lack sport-specific evidence, risking mismanagement of player health and performance. This study described dual-energy X-ray absorptiometry (DXA)-derived values by playing position, ethnicity, competition level, and seasonal timepoints. A total of 343 players (mean ± SD: age = 22.6 ± 4.6 years; stature = 182.0 ± 6.9 cm; body mass = 79.1 ± 8.6 kg) from the English Premier League (n = 76) and English Football League (n = 267) completed 939 scans over a 10-year period (2014–2024) using DXA (Lunar iDXA, GE Healthcare), with repeat measurements taken across the season. Players were sub-classified as Goalkeepers (n = 32), Central Defenders (n = 55), Wide Defenders (n = 64), Central Midfielders (n = 73), Wide Midfielders (n = 62), and Forwards (n = 57). Body composition ranges specific to position were identified for bone mass (3.5–4.2 kg), lean mass (61.2–69.6 kg), fat mass (9.1–13.5 kg), and percentage body fat (11.6–15.4%). Significant differences in bone, lean, and fat mass were observed between playing positions, ethnicity, and league level ( p  < 0.050). Across a single season, fat-free mass increased significantly, while fat mass decreased (both: p  < 0.001), indicating positive physiological adaptations from moderate body mass increases rather than performance concerns. These findings indicate that body fat values above the commonly cited < 10% threshold are regularly observed in elite male footballers, suggesting the need for more individualised targets over generic team-wide standards. Providing the largest criterion-measured dataset for professional male footballers, this study supports athlete-centred, position-specific decision-making to optimise player health and performance.