Within-game performance decrements in relation to peak fat oxidation, Fatmax and peak oxygen uptake in elite male footballers

This study investigated whether fat oxidation capacity is associated with sustained physical performance during the final 30 minutes of elite football match play.Twenty-four professional male football players (age: 24.9 ± 4.0 years; V ̇O2peak : 59.1 ± 5.7 ml/min/kg) from the Danish Superliga completed laboratory testing to determine peak fat oxidation (PFO), Fatmax, and V ̇O2peak .From match tracking data, distances covered within speed zones, number of runs, and peak speed were analysed for full-match and changes between the first 60 and final 30 minutes.Correlations between laboratory and match variables were assessed.PFO was (mean ± SD) 0.48 ± 0.16 g/min (range: 0.24-0.78),Fatmax was 43 ± 10 %V ̇O2peak (31-61), and V ̇O2peak was 59.1 ± 5.7 ml/min/kg (49.7-71.3).Players covered 11,216 ± 789 m during a full match, including 899 ± 323 m > 20 km/h and performed 79 ± 29 high-intensity runs.PFO normalized to fat-free mass (PFO/FFM) was significantly correlated with attenuated declines in number of decelerations (r=0.42,P=0.042) in the final 30 minutes, whereas no other correlations with sustained physical performance variables were observed.V ̇O2peak was associated with total distance (r=0.59,P=0.002), but not with performance decrements.Peak fat oxidation may play a modest but significant role in supporting repeated high-intensity decelerations late in games in male elite footballers.V ̇O2peak was correlated to overall running performance but appears less informative for fatigue resistance.