Impact of Weekly Training Load and Match Load on Next-Day Neuromuscular Fatigue in Elite Football Players: A Longitudinal Observational Study

Elite footballers experience substantial external loads in training and match play that may impair neuromuscular function. This study examined associations between accumulated weekly training load and single-match load with next-day hamstring and hip strength. Twenty-four professional male outfield players were monitored across 15 non-consecutive microcycles. GPS-derived metrics (e.g., total distance, high-intensity and sprint distance, high-intensity actions, sprints, accelerations and decelerations) were aggregated for training and for matches. The morning after each match (i.e., 12–18 h), eccentric hamstring strength (Nordic hamstring exercise), prone isometric hamstring force, and 45° hip adductor and abductor squeeze forces were assessed. Missing strength values (7–23%) were imputed, load variables were reduced using principal component analysis, and linear mixed-effects models were fitted with player as a random intercept. Higher overall match load was associated with lower next-day Nordic hamstring force ( ≈ − 5 N per + 1 SD; p = 0.046), whereas weekly training load was not related to any strength outcome (p = 0.260–0.770). Match intensity distribution was positively associated with next-day adductor force ( ≈ + 12 N; p = 0.046), while isometric hamstring and abductor forces were unaffected. These findings indicate that intense match play produces measurable next-day eccentric hamstring fatigue, supporting Nordic testing as a practical post-match monitoring tool.