This study aimed to investigate the influence of match-contextual difficulty, specifically considering match location and the quality of opposition, on the weekly external load experienced by professional Brazilian soccer players over a competitive season. The main findings revealed that matches with less difficulty were associated with a significantly higher external load on MD-4, MD-3, and MD-2, compared to more difficult matches. However, higher mechanical work was observed during more difficult matches on MD-3 and MD-1.
A significant fluctuation in external load measures throughout the competitive period was reported, with the highest values observed during the middle weeks and the lowest values in the final weeks of the season. Previous studies have reported similar variations in weekly external load based on distance and accelerometry measures [20, 21]. These studies noted minimal external load variations during the first and last weeks of the season, while the greatest variations occurred during the in-season periods (i.e., middle weeks). This variation in external load could be attributed to several factors, including the accumulation of fatigue over the season [20], the intensity of the matches played during specific weeks [22], and the individualized recovery strategies employed [23]. Coaches and practitioners should take this weekly variation into account when programming training sessions and managing training load to optimize performance and minimize injury risk.
The position-specific analysis highlighted significant differences in the physical demands experienced by players in different on-field roles. External defenders and central midfielders exhibited higher weekly physical demands during the competition, while central defenders and forwards demonstrated the lowest running demands. A recent study underscored significant differences in external load demands based on players' positions during both training and official matches [24]. In the mentioned study [24], the wingers showed the highest external load demands during matches, while central backs and midfielders present the lowest demands. Another study on 18 professional soccer players found that the wing-backs achieved only 64% of match sprint peaks during microcycles, while other positions either matched or exceeded match values (107% for center-backs, 100% for center midfielders, and 107% for center forwards) [25]. These findings emphasize the importance of tailoring training regimens and load management strategies to the specific requirements of each position, encouraging coaches to develop position-specific training programs to enhance player performance.
Notable differences in external load measures based on match-contextual difficulty were reported in the present study. Specifically, matches characterized by low match-contextual difficulty were associated with significantly higher external load in certain weeks (MD-4, MD-3, and MD-2) compared to matches with high match-contextual difficulty. In contrast, higher mechanical work was observed during matches of higher contextual difficulty on MD-3 and MD-1. This suggests that players may engage in additional high-intensity activities, such as sprints and accelerations, when facing stronger opposition or more demanding playing conditions. These findings align with a recent study conducted on 22 professional soccer players [26], which found that players covered greater distances in sprints during matches against weaker opponents compared to matches against intermediate and strong opponents [26]. Players tend to exert more physical effort in matches perceived as less challenging, perhaps due to increased offensive opportunities or reduced defensive pressure.
Multiple studies consistently demonstrate that competing at one's home venue offers several advantages to soccer teams, including heightened goal-scoring prowess, improved passing proficiency, and enhanced disciplinary behavior [27]. The consequential home advantage effect profoundly influences soccer strategies, compelling teams to tailor their playing styles accordingly [27]. In fact, significant interactions have been identified between match location and the demands on TD, HSR, and SR distances [28], indicating that the match location (e.g., home or away) notably impacts external load demands. In this context, our findings underscore the importance of considering the location of matches and the quality of opposition when planning training loads. Coaches should adopt a nuanced approach, adjusting training intensity and volume based on the contextual factors surrounding each match.
The current study has certain limitations that warrant discussion. First, the study was limited a relatively small team sample size. Second, it did not incorporate internal load measurements, such as the rate of perceived exertion-based training load, heart rate-based metrics, and variations in well-being, which could have provided a more comprehensive understanding. Future research should consider including additional variables related to the contextual difficulty of matches, such as the number of training days leading up to the match. Additionally, it's important to note that this study exclusively focused on starting players who participated for most of the match (i.e., over 60 minutes). Future investigations should extend their scope to include substitute players and consider the effects of congested match schedules.
Notwithstanding the above-mentioned limitations, the present study highlights some potential practical implications. The observed variations in external load across different weeks and positions highlight the need for individualized training programs that consider the specific demands faced by each player. Furthermore, our findings emphasize the importance of incorporating match-contextual difficulty into load management strategies, as it significantly impacts the physical demands placed on players. Coaches should leverage this knowledge to optimize player performance, minimize injury risk, and enhance overall team success.