###### Abstract  
The aim of this study was to analyze and compare the external load demands of players from the Spanish women's national football teams across the U-17, U-20, and senior categories during their respective FIFA World Cup participations. Key kinematic variables were assessed via global positioning systems (GPS), including total distance (TD), high-speed running (HSR; \(\geq\)18 km\(\cdot\)h\({}^{-1}\)), sprint distance (\(\geq\)21 km\(\cdot\)h\({}^{-1}\)), accelerations (\(>\)3 m\(\cdot\)s\({}^{-2}\)), decelerations (\(<\)-3 m\(\cdot\)s\({}^{-2}\)), and high metabolic load distance (HMLD) during 3 world cups (U17, U20 and senior). Significant differences were observed between the senior team and both U-20 and U-17 in nearly all variables, with greater magnitude as the intensity of the metrics increased, showing effect sizes ranging from moderate to very large (d = 0.95 to 4.76). Positional analysis by categories showed that senior full backs (FB) and central midfielders (CM) showed higher demands compared to U-20 and U-17. For TD, senior covered more than U-17 (FB: \(p\) = 0.001; d = 1.11 | CM: \(p\) = 0.023; d = 0.97), with small differences vs. U-20 (d \(\leq\) 0.54). In HSR, both positions outperformed U-17 and U-20 (FB: \(p\)\(\leq\) 0.007; d = 0.87-1.15 | CM: \(p\)\(\leq\) 0.031; d = 0.71-1.11). In HMLD, both FB and CM displayed very large differences compared to U-17 and U-20 (all \(p\)\(<\) 0.001; d = 2.54-6.16). These findings underscore the need for progressive development of locomotor capacities from early stages, considering both age category and playing position, to facilitate a more seamless transition to elite-level football. 20251584212025158421202515842120251584212025158421202515842  
demands to reduce injury risk. A comparative study across age categories, conducted with Brazilian U-17, U-20, and senior players [3], reported a general increase in key performance indicators, such as total distance (TD) covered and high-intensity actions. Moreover, progressive increases in both TD and sprint distance were observed with advancing age among U-15, U-16, and U-17 players [4]. [PERSON] et al. (2022) [5] highlighted this by showing that professional players outperform their U-17 and U-20 counterparts in sprint distance and top speed. The greater frequency of sprints performed indicates that the capacity to sustain repeated high-intensity sprint efforts may represent a critical determinant in the progression to senior-level competition. In addition to traditional locomotor variables such as total distance, high-speed running (HSR) distance, and sprint distance, neuromuscular metrics, particularly accelerations and decelerations, have gained increasing importance in performance analysis [6]. Their direct association with repeated explosive efforts and the overall mechanical load borne by players makes them a key performance indicator [6]. These variables reflect short, high-intensity movements that do not necessarily result in large displacements but involve a high frequency of neuromuscular demanding actions. Considering these variables is especially relevant given the inherent nature of football, which involves continuous changes of direction, both with and without the ball, leading to a constant repetition of such efforts throughout the match [6]. [PERSON] et al. (2021) [7] reported that youth and collegiate players display a lower frequency of accelerations and decelerations compared to elite-level athletes, suggesting a reduced tolerance to neuromuscular load during early developmental stages. Similarly, [PERSON] et al. (2019) [3] observed significant increases in accelerative actions with age progression, reinforcing the notion that these variables are critical for distinguishing between competitive levels. In terms of playing position, central midfielders (CM) and full backs (FB) appear to record the highest values in these metrics, likely due to their constant involvement in both attacking and defensive transitions [8].