Analyzing the impact of non-participation in the FIFA World Cup Qatar 2022 on LaLiga players' physical performance.

Background: Monitoring external load demands in soccer is crucial for optimizing performance and reducing injury risk. However, events like the FIFA World Cup Qatar 2022 and unexpected interruptions can disrupt load management strategies. Understanding the impact of such events on player performance is essential for effective training and recovery strategies. Objective: This study retrospectively assessed the impact of the FIFA World Cup Qatar 2022 on the physical performance of LaLiga elite soccer players who were not part of the tournament. The aim was to analyze various external load parameters and determine the direction of their changes post-tournament. Methods: Data from 239 LaLiga players who were not selected for the World Cup were analyzed. External load parameters from 8 matches before and after the tournament were compared. Statistical analyses, including repeated measures ANOVA, were conducted to evaluate changes in performance metrics. Results: Minutes played and total distance covered showed no significant changes post-tournament. However, maximal speed decreased significantly (p < 0.001; η2p = 0.117). High-speed running parameters improved significantly (p < 0.05), except for HSRRelCount (p = 0.074; η2p = 0.013). Sprint-related variables demonstrated significant enhancements, except for SprintAbsAvgDuration, SprintMaxAvgDuration, and Sprints >85% Vel Max. Acceleration metrics showed significant improvements in Accel_HighIntensityAccAbsCount (p = 0.024; η2p = 0.021), while Accel_Accelerations showed no significant changes. Deceleration metrics remained unchanged, but Accel_HighIntensityDecAbsCount and Accel_HighIntensityDecAbsDistance increased significantly post-tournament (p = 0.002; η2p = 0.040, p = 0.001; η2p = 0.044, respectively). Conclusion: Non-participant LaLiga players demonstrated enhanced performance in most external load metrics after the FIFA World Cup Qatar 2022. These findings highlight the importance of effective load management during periods of competition interruption and suggest strategies to optimize performance and reduce injury risk. Further research should consider holistic performance metrics and internal load parameters to provide comprehensive insights into player response to mid-season tournaments.

ACTN3 XX Genotype Negatively Affects Running Performance and Increases Muscle Injury Incidence in LaLiga Football Players.

The aim of this study was to investigate the association of the ACTN3 rs1815739 polymorphism with match running performance and injury incidence in top-level professional football players. A total of 315 top-level professional football players from the first division of Spanish football (i.e., LaLiga) participated in this prospective and descriptive study. The ACTN3 rs1815739 genotype was identified for each player using genomic DNA samples. During LaLiga 2021-2022, players' performance was obtained through a validated camera system in all official matches. Additionally, the incidence of non-contact injuries was obtained by each team's medical staff according to the International Olympic Committee (IOC) statement. From the study sample, 116 (36.8%) players had the RR genotype, 156 (49.5%) had the RX genotype, and 43 (13.7%) had the XX genotype. The anthropometric characteristics of the players were similar across genotypes. However, the total running distance (p = 0.046), the distance at 21.0-23.9 km/h (p = 0.042), and the number of sprints (p = 0.042) were associated with the ACTN3 genotype. In all these variables, XX players had lower match performance values than RR players. Additionally, total and match injury incidences were higher in XX players than in RR players (p = 0.026 and 0.009, respectively). The rate of muscle injuries was also higher in XX players (p = 0.016). LaLiga football players with the ACTN3 XX genotype had lower match running performance and a higher incidence of non-contact injuries over the season.

Technical and tactical evolution of the offensive team sequences in LaLiga between 2008 and 2021. Is Spanish football now a more associative game?

The aim of this investigation was to study the technical and tactical evolution of the offensive team sequences in the Spanish football teams from 2008/09 to 2020/21. A comparative analysis including twelve variables related to the development of offensive sequences in 4940 matches was performed from 2008/09 to 2020/21 seasons of the Spanish professional football league (LaLiga). All match observations were recorded using a validated video tracking system. Multilevel linear mixed models were used to examine the differences across seasons, considering the effects of contextual variables. The number of passes per sequence (2.4 [CI: 2.2-2.5] vs 3.2 [CI: 3.0-3.4]; +33.3%), the passing accuracy (72.1 [CI: 70.6-73.5] vs 76.9 [CI: 75.4-78.3]%; +6.8%) and the average duration of the team sequences (6.4 [CI: 5.9-6.8] vs 8.3 [CI: 7.8-8.7] seconds; +25.76%) showed a small increasing trend over the seasons (P < 0.05). In contrast, variables such as the direct speed of progression (2.2 [CI: 2.1-2.3] vs 1.6 [CI: 1.5-1.7] metres/second; -24.5%), key passes (8.1 [CI: 7.6-8.5] vs 6.8 [CI: 6.3-7.2]; -15.8%), and the sequences that ended in the attacking third (64.8 [CI: 62,7-66.8] vs 57.1 [CI: 55.1-59.2]; -11.7%) or in a shot (13.0 [CI: 12.4-13.6] vs 10.2 [CI: 9.6-10.8]; -21.6%) showed a small decreasing trend from 2008/09 to 2020/21 (P < 0.05). Spanish professional football teams slightly evolved technically and tactically towards a more associative style of play that includes longer passing sequences. This evolution also involved a decreasing speed of progression and fewer technical actions such as through balls, key passes and shots.

An eight-season analysis of the teams' performance in the Spanish LaLiga according to the final league ranking.

This study aimed to analyse the performance of 5,518 collective observations of the Spanish LaLiga teams for eight consecutive seasons (from 2011-12 to 2018-19), considering the final league ranking. The teams were divided into four groups: Europe (from 1st to 6th), Upper-Middle (from 7th to 11th), Lower-Middle (from 12th to 17th) and Relegation (from 18th to 20th). The variables recorded were: Passes, Successful Passes, Crosses, Shots, Goals, Corners, Fouls, Width, Length, Height, distance from the goalkeeper to the nearest defender (GkDef), total distance covered (TD) and number of points accumulated. The main results were that: 1) Europe, being superior to the rest of the groups, showed lower values of Length from 2015-16, and lower values of GkDef from 2014-15; 2) Upper-Middle showed lower values of Length from 2015-16; 3) Lower-Middle showed fewer Shots from 2013-14, and lower values of Length, GkDef and TD from 2014-15; and, 4) Relegation barely showed significant differences between seasons in any variable. The study concludes that the teams of the Europe, Upper-Middle and Relegation groups showed quite stable performance, while the teams of the Lower-Middle group presented a worsening in different dimensions as the seasons progressed. The information provided in this study makes it possible to have reference values that have characterized the performance of the teams for each group.

Hamstring muscle injury is preceded by a short period of higher running demands in professional football players.

The aim of this study was to examine match running patterns before a hamstring muscle injury occurs during a match in male professional football players. A total of 281 male professional football players belonging to 7 teams from LaLiga were prospectively monitored over three seasons. Among these, 36 players suffered a non-contact hamstring muscle injury during an official match. The injuries were recorded by the medical staff, including the minute when the injury occurred. Running distances at different speed thresholds for 5 min and 15 min before the injury were compared to mean values of the previous 5 matches for the same time points. There were a total of 44 non-contact hamstring muscle injuries, which represents a hamstring muscle injury incidence of 3.34 injuries/1000 h of match exposure. The average time loss for these injuries was 33 ± 28 days (range 7 to 117 days). In the 15 min prior to the injury, players ran a similar distance as in control matches (p from 0.22 to 0.08). However, players ran a greater distance in the 5-min period before the injury than in control matches at 21.0-23.9 km/h (p < 0.001) and at ≥ 24 km/h (p < 0.001). The odds ratio for a hamstring muscle injury was 7.147 for those players who ran > 30.0 m at ≥ 21 km/h in a 5-min period (p < 0.001). Hamstring muscle injuries during competition were preceded by 5 min of higher running demands at > 21 km/h, compared with control matches. This suggests that a short period of unusual running increases the risk of hamstring muscle injury in professional football players.

Changes in physical and technical match performance variables in football players promoted from the Spanish Second Division to the First Division.

The aim of this study was to compare physical and technical match performance variables in football players who competed in the Spanish second division for one season and were promoted to the top (first) division in the following season. A total of 97 male outfield football players who were promoted from the second to the first division of the Spanish professional football league within the same team were analysed. Data were recorded using the TRACAB (ChyronHego, New York, USA) multicamera computerised optical tracking system during five seasons (2015-2016 to 2019-2020). A one-way ANOVA repeated measures analysis showed that players executed a greater number of high-intensity running (HIR) efforts (P < 0.001; ES: 0.258), as well as covering greater HIR distance (P < 0.010; ES: 0.106) and total running distance (TD) (P < 0.010; ES: 0.080), when they played in the first division compared with the second division. Moreover, players performed a lower number of passes (P < 0.01; ES = 0.116), short passes (P < 0.01; ES = 0.106), long passes (P < 0.05; ES = 0.067), dribbles (P < 0.001; ES = 0.146) and shots (P < 0.01; ES = 0.074) in the first division compared to the second division. No significant differences were found for any of the defensive variables evaluated. In conclusion, being promoted from the second to the first division of professional football requires players to adapt to greater physical demands and a reduced number of technical actions.

Reduced Match Exposure in the Previous 2 Matches Accounts for Hamstring Muscle Injury Incidence in Professional Football Players.

BACKGROUND: Hamstring strain injuries are one of the most prevalent injuries in football (soccer). We examined the influence of accumulated match-play exposure on the occurrence of hamstring strain injury in professional football from 2 teams (Spanish 1st Division, LaLiga) over 3 seasons, and determined specific cut-off points as indicators of injury risk. HYPOTHESIS: Overloaded players would be more likely to sustain a hamstring injury. STUDY DESIGN: Prospective, controlled, observational study. LEVEL OF EVIDENCE: Level 2b. METHODS: Playing time, total running distance, and high-speed running (>24 km/h) distance during official matches of players that sustained a hamstring injury were compared with uninjured, paired controls. Cumulative playing time and running performance of 4 matches before the injury was computed. Relative risk (RR) of injury occurrence was estimated by generalized estimating equations. Diagnostic accuracy was determined by receiver operating characteristics and the area under the curve. RESULTS: Thirty-seven hamstring strain injuries occurred, representing 23 ± 18 absence days per injury. Thirty-seven controls (uninjured players) were used as comparators. Low match-play exposures during 1 and 2 matches before injury were likely to explain injury occurrence (RR: 14-53%; P < 0.01). Metrics from the match before the hamstring muscle strain demonstrated the best accuracy to predict injury occurrence: high-speed running distance ≤328 m (sensitivity, 64%; specificity, 84%), playing time ≤64 min (sensitivity, 36%; specificity, 97%), and running distance ≤5.8 km (sensitivity, 39%; specificity, 97%). CONCLUSION: Relatively reduced competitive exposure in the previous 2 matches was associated with higher hamstring injury risk in professional football players. CLINICAL RELEVANCE: Screening simple metrics such as the accumulated match exposure during official matches and considering specific cut-off points for some running variables may be good indicators of injury risk and may assist in better individual injury management in professional soccer players.

Performance Analysis of the Spanish Men's Top and Second Professional Football Division Teams during Eight Consecutive Seasons.

The present study aimed to analyse the performance of the Spanish men's top (LaLiga1) and second (LaLiga2) professional football division teams for eight consecutive seasons (from 2011-2012 to 2018-2019). The variables recorded were Passes, Successful Passes, Crosses, Shots, Goals, Corners, Fouls, Width, Length, Height, distance from the goalkeeper to the nearest defender (GkDef) and total distance covered (TD). The main results were that (1) LaLiga1 teams showed lower values of Length from 2013-2014, and lower values of GkDef and TD from 2014-2015; (2) LaLiga2 teams showed fewer Passes and lower values of GkDef and TD from 2014-2015, and fewer Goals and lower values of Length from 2015-2016; and (3) LaLiga1 teams showed more Passes, Successful Passes, Shots and Goals and higher values of TD compared to LaLiga2 teams during the eight-season period. This study concludes that LaLiga1 teams showed fewer final offensive actions, LaLiga2 teams showed fewer Passes and Goals and the teams of both leagues played in a space with greater density (meters by player), covering less distance as the seasons passed. The information provided in this study makes it possible to have reference values that have characterised the performance of the teams.

Does player age influence match physical performance? A longitudinal four-season analysis in Spanish Soccer LaLiga.

This study aims to analyse the evolution of match running performance in relation to the age distribution of professional soccer players using a large-scale analysis. An explorational-longitudinal and retrospective study was designed and a total of 36,883 individual match observations were collected on outfield players competing across four consecutive Spanish LaLiga seasons (from 2015/16 to 2018/19), using an optical tracking system (ChyronHego). Soccer players were divided into 3 age groups: young (18-24 years old), middle-aged (25-30 years old), and seniors (31-41 years old). Relative total distance (TD/min), distance covered at 21-24 km · h-1 (HIRD/min), and > 24 km · h-1 per minute (VHIRD/min) were analysed; also, the number of efforts at 21-24 km · h-1 (Sp21) and > 24 km · h-1 (Sp24) were taken into consideration. Seasons were divided into four phases (P): P1 (matches 1-10), P2 (11-19), P3 (20-29), and P4 (30-38). The results showed that young players covered significantly greater TD, HIRD and VHIRD than the rest of the players (p < .05) in all season phases. In addition, TD significantly decreased along season phases in all player age group (p < .01). Crucially, young players performed significantly greater numbers of Sp21 and Sp24 than the rest of the players (p < .05) in all season phases. In addition, Sp21 and SP24 significantly decreased in middle-aged (p < .01) and senior players (p < .05) across the seasons. This study demonstrated that players' match running performance decreases with increasing years, especially in high-intensity running distances.

Differences in playing style and technical performance according to the team ranking in the Spanish football LaLiga. A thirteen seasons study.

This study aimed to explore the differences in playing style and technical performance according to the ranking level in Spanish football teams. The sample comprised 38 professional teams that competed in LaLiga from 2008/09 to 2020/21, with a total of 4940 matches. The teams were grouped by their final ranking position: Champion (1st); Champions League (2nd-4th); Europa League (5th-6th); middle teams (7th-17th); and relegated teams (18th-20th). Linear mixed models were used to examine the effects of the team ranking on variables related to playing style and technical performance. The F2 statistic was calculated as effect size (ES). Regarding the style of play, the Champion teams initiated offensive sequences from a more advanced field position than the remaining ranking groups with a descending effect as the ranking position decreased (p < 0.001; ES = medium). The sequence duration and passes per sequence showed a decreasing effect across ranking groups (both p < 0.001; ES = small). In contrast, the direct speed showed an increasing effect as the ranking position decreased (p < 0.001; ES = small). A decreasing effect was observed in the number of sequences ending in the final third as the ranking position decreased (p < 0.001; ES = large) while no effect was found for the sequences ending in a shot. There was a reduction effect in ball possession, passing accuracy, through balls and crosses as the teams' ranking decreased (all p < 0.001; ES = small-to-large). In summary, higher-ranked teams had an advanced starting position, longer offensive sequences, slower progression speed, more ball possession, higher passing accuracy, and more crosses and through balls than lower-ranked teams. Football coaches should consider that adopting a playing style focused on regaining the ball possession in advanced field zones and using long passing sequences can be an effective tactical strategy to improve the teams' ranking during the season.

Evolution of Tactics in Professional Soccer: An Analysis of Team Formations from 2012 to 2021 in the Spanish LaLiga.

The aim of this investigation was to explore the evolution of team formations (TFs) in a top national professional soccer league. A comparative analysis of a total of 3420 matches was performed in 32 professional soccer teams that competed from the 2012/13 to the 2020/21 season in the Spanish LaLiga. The frequency distribution of TFs across seasons presented a statistically significant change (p < 0.001). A 4.2-3.1 TF was most common from 2012/13 to 2016/17, while a 4.4.2 TF was most used from 2017/18 to 2020/2021. TFs such as 4.3.3 and 4.5.1 showed a relatively stable trend over the seasons. Overall, there was a reduction of TFs with 5 midfielders and an increase in the frequency of 2-forward formations (p < 0.001). When the ranking of teams was considered, a 4.3.3 TF was implemented with higher frequency by the Champion and teams that qualified for the Champions League (p < 0.05). However, a 4.2-3.1 TF was most frequent for teams qualified for the UEFA Europa League or teams that got relegated to an inferior category (p < 0.05). These findings highlight that teams competing in LaLiga evolved from the implementation of very few TFs led by the 4.2-3.1 TF, towards a more diverse scenario with a greater variety of tactical positional structures.

Is there any relationship between match running, technical-tactical performance, and team success in professional soccer? A longitudinal study in the first and second divisions of LaLiga.

The aim of this study was to analyze the association between teams' success at the end of the season and match running, and technical-tactical performance in two professional soccer leagues. Match running, and technical-tactical performance data were collected during two consecutive seasons. A Factor Analysis was conducted to reduce the number of performance variables into a fewer number of factors. The scree plot with parallel analysis revealed that five factors should be retained. Then, a multiple linear regression analysis was performed to explain which variables and factors were more associated with teams' success at the end of the season. The main findings of this study were that factor 3, which was correlated with goals scored, possessions ending with a goal, shots on target, goals from set plays, goals from a direct free kick, offsides, and goals conceded, was the most important contributor to teams' success (ß = 0.66). In addition, this study observed a significant interaction (p = 0.001) between the second division of LaLiga and factor 2, which correlated with total distance (TD), sprinting distance (SPD), and sprinting actions (SPA) when opponent team owns the ball, tackles, shots inside the box, and fouls received. This implies that factor 2 had a different effect on the total points at the end of the season depending on the league. However, factor 2 had no effect on the first division. In conclusion, technical-tactical performance variables were usually more closely linked to the team's success in both leagues than match running performance data. Regarding the technical-tactical performance, teams may focus on drills that promote goal situations, shooting accuracy, the total of shots performed in match play, and set pieces. However, defensive skills need to be reinforced considering the importance of goals conceded for team success in both divisions. When it comes to the match running performance, teams are encouraged to focus on offensive actions, in which they possess and run with the ball (especially at high speed) and defensive actions in which the players perform continuous and high-intensity physical efforts to prevent the opponents from scoring, avoid counterattacks, stay compact, and defend the area and goal.

Effect of Increasing the Number of Substitutions on Physical Performance during Periods of Congested Fixtures in Football.

(I) This study aimed to evaluate the impact on physical demands induced by FIFA's new rule implemented based on the number of substitutions caused by COVID-19. (II) Sixty-six matches were analysed in peak periods (microcycles of three matches in a week) in the competition period before and after the pandemic. The variables collected were organised by team (22 from LaLigaTM SmartBank 2019-2020) for a total of 132 team records and 1077 player performance reports using a multi-camera tracking system and Mediacoach® software. Physical performance variables were analysed in the first half, second half and whole match, thus determining the individual and collective performances of the team. (III) This study shows how, despite the increase in substitutions allowed with the new rule, physical performance increased in some variables in the congested periods (e.g., total distance run and distance run in the first and second halves). Additionally, the players' physical performance involved in a substitution was greater than it was for players who completed the game. (IV) The new substitution rule helps to maintain and even improve physical performance. This measure could improve intensity levels in both individual and team performance. It could even safeguard the physical integrity of the players by reducing the risk of injury, as fewer players have to play the full match.

The Five-substitution Option Enhances Teams' Running Performance at High Speed in Football.

The aim of this investigation was to describe how the introduction of the five-substitution option affected football teams' running performance. A comparative analysis was performed in 17 professional football teams for the 2019-2020 (up to three substitutions) vs 2020-2021 (five substitutions option) seasons in LaLiga. The five-substitution option increased the number of substitutions (from 2.9±0.1 to 4.2±1.0 substitutions/match, respectively; p<0.01, Effect Size (ES)=2.11) but it did not change the time selected for the first substitution (from 57.5±13.0 to 56.2±13.7 min; p=0.06, ES=0.1). Total running distance was similar between seasons but running distance at 21.0-23.9 km/h (from 3.0±0.4 to 3.2±0.4 km; p=0.01, ES=0.6) and at≥24.0 km/h (from 3.0±0.6 to 3.2±0.5 km; p=0.01, ES=0.3) were higher with the five-substitution option. These increases were associated with a higher distance covered by starting players (p<0.05) rather than an effect of substitute players.: With the five-substitution option, team coaches increased the number of substitutions per match which enhanced the possibilities of the team's staff to manage players' physical load. The five-substitution option allowed also increased running performance at≥21.0 km/h during the matches.

Evolution of physical and technical parameters in the Spanish LaLiga 2012-2019.

This study aimed to examine the position-specific evolution of technical and physical parameters in the Spanish LaLiga over an eight-season period. Match performance data of players were analysed for eight consecutive seasons from 2012/2013 to 2019/2020. A total of 32,775 individual match observations were analysed using a computerised tracking system (TRACAB, Chyronhego, New York, USA). The players were classified into five positional roles: central defenders (CD; match observations = 9,089), external defenders (ED; match observations = 7,876), central midfielders (CM; match observations = 8,276), external midfielders (EM; match observations = 3,949), and forwards (F; match observations = 3,585). Generalised linear models were used to analyse the differences in players' match performance according to the season and playing position. Total distance decreased by 3.2% in the final season versus the first season (p < 0.01, effect size = 0.37) in all playing positions. The number of efforts made at high-intensity running (HIR) increased across the eight seasons (ranging from 14.6% in ED to 9.2% in EM). However, whereas CD (+8.2%), ED (+9.5%), CM (+9.3%), and F (+8.0%) increased HIR distance from 2012 to 2020, no significant differences were found for EM (+1.7%). Overall, no differences were found in the number of total passes, short passes, long passes, and pass accuracy. Interestingly, CD increased the number of total passes (30.60%), short passes (31.5%), and long passes (26.5%). Finally, players performed 46.0% less tackles, 40.8% less clearances, and 10.0% more interceptions over the eight-season period. These findings may be useful for position-specific technical and physical training and talent identification.

When and how do professional soccer players experience maximal intensity sprints in LaLiga?

OBJECTIVES: To 1) examine the periods in which maximal intensity sprints occurred during professional soccer matches and 2) analyze the maximal intensity sprints registered in match play considering the effect of playing position and other contextual variables. METHODS: A total of 1252 match observations were collected from 277 male professional players. Sprinting actions at maximal intensity were analyzed during 30 matches, and both contextual and performance variables were collected using performance tracking systems. RESULTS: Maximal intensity sprints were more frequent in the first and last periods of the match (0'-15'; 75'-90'), regardless of the playing position (χ2=23.01; p=0.29; ES=0.07). These sprints were usually non-linear actions without possession of the ball and had different tactical purposes depending on the position. The mean sprint duration ranged from ~4.9 s to ~9 s, the mean distance covered ranged from ~30 m to ~55 m, while the mean maximum velocity was between ~30.12 and ~32.80 km/h depending on the tactical purpose and playing position. CONCLUSION: Professional soccer players need to be prepared during warm-ups for maximal intensity sprints in the first period of the match as well as maximal intensity sprints under high fatigue conditions given the frequency of sprints in the last period of the match. Also, training drills should be designed with a special focus on non-linear sprints without possession of the ball, based on the main tactical purpose of each position (e.g., CD: interceptions; MF: recovery runs; FB, WMF and FW: run the channel).

Influence of the COVID-19 lockdown on Spanish professional soccer teams' external demands according to their on-field ranking.

The main objective of this study was to analyse the changes in external demand parameters (e.g., total distance, high-speed running distance, accelerations/decelerations) in Spanish professional soccer teams after the COVID-19 lockdown considering their on-field ranking (i.e., teams whose ranking worsened after the COVID-19 lockdown [WRS] vs. teams that improved their ranking after the COVID-19 lockdown [IMP]). A total of 23,527 individual match observations were collected on players competing during the 2019/20 season in the First Spanish Professional soccer League (LaLiga). Goalkeepers and players who participated for less than 10 minutes in each match were excluded. Relative total distance (TD/min), distance covered at 21-24 km · h-1 (HIRD/min) and > 24 km · h-1 per minute (VHIRD/min), high metabolic load distance (HMLD), and the number of accelerations (3 m/s2) and decelerations (< 3 m/s2) performed were analysed by the ChryonHego video-tracking system. These variables were analysed during two differentiated periods, before the COVID-19 lockdown (i.e., 27 matches) and after the COVID-19 lockdown (i.e., 11 matches), and teams were classified into two groups according to their ranking (i.e., WRS vs. IMP). R-Studio was employed for data analysis and a mixed linear model was conducted. A decrease in external demands in all teams after the COVID-19 lockdown was observed, and this decrease was greater in WRS. These results suggest that, after an inactive period (i.e., the COVID-19 lockdown), teams that return with better physical performance, mainly related to high-intensity actions, have more possibilities of improving their final qualifying position.

High metabolic load distance in professional soccer according to competitive level and playing positions.

Background: High metabolic load distance provides global information about the soccer players' total high-intensity activities. Thus, this study aimed to examine the Spanish professional soccer players' high metabolic load distance profile, comparing competitive level and playing positions. Methods: A total of 18,131 individual match observations were collected from outfield players competing during the 2018/2019 and 2019/20 seasons in the First and Second Spanish Professional Soccer Leagues (LaLiga™). High Metabolic Load Distance (HMLD; distance covered with a power consumption above 25.5 W·kg-1 and accelerations or decelerations (e.g., accelerating from 2 to 4 m·s-2 for 1 s) were included), and HMLD per minute (HMLDmin) were analyzed by the ChryonHego® video-tracking system. Players were classified according to their playing position as follows: Central Backs (CB), Full Backs (FB), Center Midfields (CM), Wide Midfields (WM), and Forwards (FW). Results: No differences between competitive levels were found in any variable when all players were analyzed conjointly except for HMLDmin overall and during the second half. However, when playing positions were considered, differences between competitive levels were observed in all positions, mainly in HMLD and HMLD during the first-half variables. In addition, several differences between playing positions were observed, with CB presenting the lowest values in all variables compared to their counterparts in both competitive levels, whereas CM in First Division and WM in Second Division showed the highest values in the HMLD variables. Discussion: The findings are of interest to analyze the HMLD in professional soccer players, enabling the adaptation and individualization of training in this population according to the competitive level and specific playing position of each player.

Tell me how and where you play football and I'll tell you how much you have to run.

The aim of this study was to describe the team accumulated physical response per minute considering only the effective playing time (EPT) attending to different contextual and strategic variables in the Spanish Football First Division (LaLiga Santander). A sample of 2,959 performances was included in the analysis, considering a 4-year period of analysis (from 2016-17 to 2019-20). The physical variables were: total distance covered with (DTminPOS) and without (DTminNOpos) possession of the ball, and distance covered at > 21 km·h-1 with possession (DT21minPOS) and without (DT21minNOpos). Two contextual variables, i.e. Place (Home/Away) and Score (Lost/Draw/Win), and two strategic variables, i.e. level of effective playing time (LevelETP) and level of possession of the ball (LevelPOS), were analysed. The teams ran more without possession of the ball than with possession; nevertheless, the teams that had less possession of the ball had higher values in the distance covered at > 21 km·h-1 with possession of the ball and vice versa. Furthermore, the strategic variables also had influence on the physical response (DT and DT21) of the teams,LevelETP and LevelPOS, although with interactive effects: longer playing time, less accumulated distance, and greater possession, greater accumulated distance in the defensive phase, both per min. The findings of this study may offer important practical implications to practitioners in order to assess physical performances of the players in matches, because it is crucial to integrate in the analysis the different contextual and strategic variables where the match has taken place to assess performances of the teams.