A New Approach for Training-load Quantification in Elite-level Soccer: Contextual Factors

Abstract

The aims of this study were to analyse the physical responses of professional soccer players during training considering the contextual factors of match location, season period, and quality of the opposition; and to establish prediction models of physical responses during training sessions. Training data was obtained from 30 professional soccer players from Spanish La Liga using global positioning technology (N=1365 performances). A decreased workload was showed during training weeks prior to home matches, showing large effects in power events, equivalent distance, total distance, walk distance and low-speed running distance. Also, the quality of the opposition also affected the training workload (p<0.05). All regression-models showed moderate effects, with an adjusted R2 of 0.37 for metabolic-work, 0.34 for total distance covered, 0.25 for high-speed running distance (18–21 km·h−1), 0.29 for very high-speed running distance (21–24 km·h−1), 0.22 for sprint running distance (>24 km·h−1) and 0.34 for equivalent distance. The main finding of this study was the great association of match location, season period and quality of opposition on the workload performed by players in the training week before the match; and the development of workload prediction-models considering these contextual factors, thus proposing a new and innovative approach to quantify the workload in soccer.

How does the workload applied during the training week and the contextual factors affect the physical responses of professional soccer players in the match?

“…11,12 Concerning to the workload developed by players in match across the season, this study showed variability between the different metrics analysed: whereas players covered a greater m-TD in the middle period compared to the other periods, the highest m-HIRD and m-SPD were found in the final period of the season. The literature shows controversy about the season period: several authors showed higher total distance and high-intensity distance covered in the final period compared to the first and middle period, 15,17 Guerrero-Calder on et al 2 found the greatest TL in the middle period, whereas other authors have found no significant TL variations over the season. 7 These discrepancies between authors may be due to the different leagues analysed; Mohr et al 17 and Rampinini et al 15 analysed the Italian First Division, J. Malone et al 7 analysed the English Premier League, Guerrero-Calder on et al 2 analysed the Spanish First Division and the present study was performed with Spanish First and Second Division teams.…”

“…The literature shows controversy about the season period: several authors showed higher total distance and high-intensity distance covered in the final period compared to the first and middle period, 15,17 Guerrero-Calder on et al 2 found the greatest TL in the middle period, whereas other authors have found no significant TL variations over the season. 7 These discrepancies between authors may be due to the different leagues analysed; Mohr et al 17 and Rampinini et al 15 analysed the Italian First Division, J. Malone et al 7 analysed the English Premier League, Guerrero-Calder on et al 2 analysed the Spanish First Division and the present study was performed with Spanish First and Second Division teams. Nonetheless, these results also showed the lowest values in the initial period for all metrics (m-TD, m-HIRD and m-SPD).…”

“…In recent years, an increased number of studies have also highlighted the importance to contextualize the load monitoring. [1][2][3] This study aimed to determine whether the match physical output can be predicted from the TL considering several contextual factors such as playing position, season period, playing style or quality of opposition within the analysis. The factors playing position and season period affected the physical responses analysed in competition (i.e., m-TD, m-HIRD and m-SPD).…”

“…Moreover, recent studies have analysed how these contextual factors affected the load across the training week. [1][2][3] Rago et al 3 found higher total distance and high-intensity distance in the training-week after an away-match and after playing against a weak team. In contrast, Brito et al 1 showed lower load on the training-week before and after playing against a top team.…”

“…Soccer is a complex sport with a myriad of factors that may affect players' physical performance. [1][2][3][4] Competing at a high-level is increasingly challenging and players must attain optimal physical readiness to withstand the competition demands. 5,6 Therefore, monitoring and quantifying the players' workload is paramount to optimising performance and reducing the injury risk.…”