This study aimed to identify the effects of different pitch configurations on youth players positional and physical performances. Forty players participated in a Gk + 5vs5 + Gk small-sided game under four conditions: regular condition (regular), pitch with the direction of competitive matches; sided condition (sided), goals were changed to width; different pitch orientation (≠orientation), performed in side-to-side line compared to competitive matches; dynamic pitch (dynamic), boundaries were randomly changed every minute by: regular pitch; decrease 6 m width; diamond shape. The following variables were considered: players' effective playing space, distance between teammates' dyads time spent synchronized, average speed and a ratio between the distance covered at different intensities and distance covered while recovering. Overall, players exhibited better performances in pitches that are more representative of the environmental information seen during competitive matches (regular and ≠orientation). However, coaches may also use different boundary conditions to promote the players' ability to adapt to different context information.

The purpose of this study was to analyse the effect of players' dismissals on the outcome of attacks in elite futsal matches, and to establish the performance profile of the attacks made in numerical superiority by elite futsal teams. One hundred and twenty five attacking game situations in numerical superiority (dismissal of opponents from defensive team) were analysed from the regular season of the Spanish professional Futsal League. The effect of contextual-related variables (quality of opposition, match-location, match-periods, opponent team's fouls, match-status, attack-duration and match-type) on goal effectiveness was analysed using binomial logistic regression and two-step cluster analysis. Results from the binary logistic regression showed that the highest attack effectiveness was achieved when the teams play at home, perform the attack during minutes 33-36 and the opposing team has 3 fouls. Secondly, the two-step cluster analysis technique allowed identifying four types of attacks when the teams were playing with numerical superiority. The results showed the great importance (in order) of match-type, match-status, attacking team's fouls, match-period, quality of opposition, opposing team's fouls, match-location, goal situation, and attack duration. The identified trends may help coaches to design the superiority/inferiority scenarios more specifically during training and to monitor them during competition.

during the competitive season of professional football teams. Design: Prospective Cohort study. Setting: Controlled laboratory environment. Participants: Seventy-one players volunteered to participate. Main outcome measures: In the pre-season, maximal hip adductor strength was measured by means of the isometric adductor squeeze test. Hip adductor strength, normalized by body mass, was compared between players who suffered a groin injury (n ¼ 18) vs uninjured players (n ¼ 53). Risk ratios (RR) were used to evaluate the likelihood of players to suffer this type of injury. Results: Most of the reported groin injuries occurred during competitive matches (5.5 per 1000 match hours). Maximal isometric hip adductor strength was lower in the groin-injured group compared with their uninjured counterparts (429.8 ± 100 vs 564 ± 58.7 N, d¼ 1.58 and 5.40 ± 1.27 vs 7.71 ± 0.89 N/kg, d¼ 1.88, respectively). Results revealed that values of maximal isometric adductor strength lower than 465.33 N increased the probability to suffer a groin injury by 72%. Furthermore, values of force relative to body mass lower than 6.971 N/kg increased the probability to suffer a groin injury by 83%. Conclusion: The assessment of Hip adductor strength, in addition to other measurements, might help practitioners to determine the probability of suffering an overuse groin injuries in elite football players.

Elite soccer teams that participate in European competitions need to have players in the best physical and psychological status possible to play matches. As a consequence of congestive schedule, controlling the training load (TL) and thus the level of effort and fatigue of players to reach higher performances during the matches is therefore critical. Therefore, the aim of the current study was to provide the first report of seasonal internal and external training load that included Hooper Index (HI) scores in elite soccer players during an in-season period. Nineteen elite soccer players were sampled, using global position system to collect total distance, high-speed distance (HSD) and average speed (AvS). It was also collected session rating of perceived exertion (s-RPE) and HI scores during the daily training sessions throughout the 2015-2016 in-season period. Data were analysed across ten mesocycles (M: 1 to 10) and collected according to the number of days prior to a one-match week. Total daily distance covered was higher at the start (M1 and M3) compared to the final mesocycle (M10) of the season. M1 (5589m) reached a greater distance than M5 (4473m) (ES = 9.33 [12.70, 5.95]) and M10 (4545m) (ES = 9.84 [13.39, 6.29]). M3 (5691m) reached a greater distance than M5 (ES = 9.07 [12.36, 5.78]), M7 (ES = 6.13 [8.48, 3.79]) and M10 (ES = 9.37 [12.76, 5.98]). High-speed running distance was greater in M1 (227m), than M5 (92m) (ES = 27.95 [37.68, 18.22]) and M10 (138m) (ES = 8.46 [11.55, 5.37]). Interestingly, the s-RPE response was higher in M1 (331au) in comparison to the last mesocycle (M10, 239au). HI showed minor variations across mesocycles and in days prior to the match. Every day prior to a match, all internal and external TL variables expressed significant lower values to other days prior to a match (p<0.01). In general, there were no differences between player positions. Conclusions: Our results reveal that despite the existence of some significant differences between mesocycles, there were minor changes across the in-season period for the internal and external TL variables used. Furthermore, it was observed that MD-1 presented a reduction of external TL (regardless of mesocycle) while internal TL variables did not have the same record during in-season match-day-minus.

The aim of this study was to identify the influence of prior knowledge of exercise duration on players' pacing patterns during soccer small-sided games. Twenty semi-professional male soccer players participated in this study. In the first game scenario, players were not informed how long they would be required to play the small-sided game and the activity was terminated after 20 min (Unknown Condition). In the second game scenario, players were told that they would play the small-sided game for 10 min, but immediately after completing the 10-min game, they were asked to complete another 10 min (Partially Condition). In the third game scenario, players were instructed that they would play the small-sided game for 20 min and then they completed the 20-min game (Known Condition). The results presented a tendency of higher values in all performance variables in the [0'-10'] min compared with the [10'-20'] min. As the players' previous knowledge about the tasks duration increased, the performance between two moments tended to be similar. Considering the entire 20-min game duration, the Partially Condition of the exercise was the most demanding condition. In conclusion, the knowledge of shorter durations of the exercise seems to lead to an increase of exercise duration demand, and longer exercise durations possibly tend to decrease differences between full knowledge and not knowing the exercise duration.

This study examined effects of player roles on interpersonal patterns of coordination that sustain decision-making in 1-vs-1 sub-phases of football in different field locations near the goal (left-, middle- and right zone). Participants were fifteen U-16yrs players from a local competitive amateur team. To measure interpersonal patterns of coordination in the 1-vs-1 dyads we recorded: (i) the relative distance value between each attacker and defender to the centre of the goal, and (ii), the relative angle between the centre of the goal, each defender and attacker. Results revealed how variations in field locations near the goal (left-, middle- and right-zones) constrained the relative distance and relative angle values that emerged between them and the goal. It reveals that relative position of the goal is a key informational variable that sustained participants' behaviours for dribbling and shooting. Higher values of relative distance and angle were observed in the middle zone, compared to other zones. Players' roles also constitute a constraint on the interpersonal coordination for dribbling and shooting. Additionally, it seems that players' foot preference constrains the dynamics of interpersonal patterns of coordination between participants, especially in left and right zones. The findings suggest that to increase participants' opportunities for action, coaches should account with field positions, players' roles and preference foot.

This study aimed to identify Career Indicators (CIs) over the stages of career development (Initiation/Development, Mastery, and Discontinuation stages) in the retirement stage of Portuguese football players. Three thousand five hundred retired Portuguese football players that played between 1960 and 2018 were considered in this study. A path analysis was performed to identify the standardized direct and indirect effects of the CI at each stage of career development, on Portuguese football players’ retirement age. The proposed model highlighted that the relationship between the CI number of seasons as a youth player, number of seasons as a youth player in top 3 clubs, age of first registration as a senior player, number of seasons as a senior player, number of seasons as a senior player in top 3 clubs, number of total games as a senior player, age of the last best result age achieved, number of games in the retirement season, and discontinuation stage length contribute to explain 40% of the retirement age of Portuguese football players. Results allowed the understanding of the influence of each stage of career development on career length. According to the Holistic Athletic Career Model, it was the first attempt to create a predictive model of CI of athletic variables. Further research should be developed to incorporate some mediator variables such as players’ performance levels and achievement to improve the explanation of the development of football players’ careers and retirement.

The aim of this study was to identify the effects of adding spatial references during football small-sided games in youth players' tactical and physical performance. Twelve under-15 players performed a Gk+ 6v6+ Gk game under two playing conditions: (i) without spatial references (CONTROL condition); (ii) with spatial references, by dividing equally the pitch into three corridors and three sectors (experimental situation, LINES). Players' positional data was used to compute time-motion and tactical-related variables. The results revealed that performance under LINES situation increased the regularity in the zones occupied (~14%, Cohen's d: 0.5; ±0.3; p = 0.003) and in the distance between teammates' dyads (~19%, 0.9; ±0.2; p < 0.001). Oppositely, LINES condition decreased the longitudinal synchronization of players' displacements (0.4; ±0.2; p = 0.002), players' average speed (0.5; ±0.3; p = 0.002) and distance covered at lower (0.9; ±0.3; p < 0.001) and moderate speed (0.5; ±0.3; p < 0.001). Adding spatial references seems to promote a more structured pattern of play and increase positional regularity. However, coaches should be aware that this constraint may decrease the synchronization between players. Overall, these findings may be generalized to most invasion team sports.

This study examined the effects of induced mental and muscular fatigue on soccer players' physical activity profile and collective behavior during small-sided games (SSG). Ten youth soccer players performed a 5vs5 SSG under three conditions: a) control, playing without any previous activity; b) muscular fatigue, playing after performing a repeated change-of-direction task; c) mental fatigue, playing after completing a 30 min Stroop color-word task. Players' positional data was used to compute time-motion and tactical-related variables. The muscular fatigue condition resulted in lower distances covered in high speeds (∼27%, 0.3; ±0.5) than the control condition. From the tactical perspective, the muscular fatigue condition resulted in lower distance between dyads and players spent ∼7% more time synchronized in longitudinal displacements than the control condition (0.3; ±0.3). Additionally, players spent ∼14% more time synchronized with muscular fatigue than with mental fatigue (0.7; ±0.3). The mental fatigue condition resulted in a very likely more predictable pattern in the distance between dyads than in muscular fatigue condition (0.4; ±0.2). Also, the mental fatigue possibly decreased the teams' stretch index when compared with control (0.2; ±0.3) and likely increased compared with muscular fatigue (0.5; ±0.5). The better levels of longitudinal synchronization after muscular fatigue, might suggest the usage of tactical-related tasks after intense exercise bouts. The lower physical performance and time spent longitudinally synchronized after mental fatigue, should alert to consider this variable before matches or training activities that aim to improve collective behavior.

The concern with the performance of football referees has opened lines of investigation in areas such as technical and physical performance. Theoretical and analytical gaps regarding the causes of their performances in a holistic perspective are scarce. The purpose of this study is to understand how various processes of personal, career development and contextual nature influences the classification of football referees. The literature review on excellence and the performance of the referees allowed to define a model that contemplates three distinct areas: 1) personal experience; 2) sports course; 3) surrounding context. The model to understand the causes of the performance of the Portuguese referees was obtained by comparing the classification of referees for national boards between the periods of 2009-10 and 2018-19 with the relative data to their age, experience as a federated player and referee, region density and proximity to peers of national board. The results show that the performance of the referees is influenced by a set of processes such as individual experience, sporting background and the context. This article opens a new perspective on the referees' training process. Its content may constitute an important insight for the implementation of referee training programs, namely at the base.