Effects of pitch spatial references on players' positioning and physical performances during football small-sided games

The effects of individual and collective variability on youth players' movement behaviours during football small-sided games

This study aimed to identify the effects of playing with additional individual (IND), collective (COL) or individual-collective (MIX) variability on youth football players' performance during small-sided games. Twelve youth football players (U17, age = 16.1 ± 0.9 years) played a goalkeeper (Gk) + 6 outfield players a-side (Gk+6vs6+Gk) under four conditions: (i) playing in the 1:2:3:1 formation without any other rule (control condition, CTR); (ii) 1:2:3:1 formation with additional body restrictions changing each minute (individual condition, IND); (iii) using different tactical formations modified each minute (collective condition, COL; (iv) using different tactical formations and body restrictions varied each minute (individual-collective condition, MIX). Generally, there were similar behaviours across conditions, especially for the CTR and the MIX. Nevertheless, the CTR condition presented moderate higher values in the lateral direction (p ≤ .05), while also higher longitudinal synchronization compared to the IND (p ≤ .05). The COL condition presented higher spatial exploration (p ≤ .05), which may justify the higher values for distance covered while running and sprinting (p ≤ .05). Overall, coaches may use the IND condition to refine players' technical actions, while the COL condition to develop players' ability to perform in different playing positions and team structures.

How many creatives are enough? Exploring how manipulating the number of creative players in the opposing team impacts footballers' performance during small-sided games

This study explored how varying the number of creative opponents affects youth players' performance during football small-sided games (SSGs). Initially, 60 players from 3 different age groups with n = 20 in each (under-9, U9; under-11, U11; and under-13, U13) were tested during SSGs to rank them according to their creative potential. Based on these rankings, four players shown to possess with a medium creative potential were assigned to the intermediate team for each age group. This team competed against a team on which players with high creative potential were progressively included (from one to finally all four players, 1C to 4C) during a 4-a-side plus goalkeeper SSG. The results showed that U9 players increased the individual space explored when facing more creative opponents (p = .012), while the U11 (p = .026) and U13 (p < .001) only increased when facing 2C and 3C. Playing against more creative opponents induced more variability in the distance to own (p = .046) and the opponent team's centroid (p = .046) in the U9, regularity in the U11 (team centroid, p < .001; opponents' centroid, p = .001) and lower regularity in the U13 (team centroid, p = .013 opponents' centroid, p = .009). These distinct movement patterns seemed to reflect the differences in players' perceptual and motor skills. A higher creative score was found against 1C (vs 2C and 4C, p = .006) and 3C (vs 4C, p = .006) in the U9. The results from the effect sizes indicated higher values on the players' attempts, fluency and versatility when facing 1C to 3C, whereas a clear decrease was observed against 4C for all age groups. Hence, moderate and high demanding scenarios prompt the emergence of new behaviours while extremely high demanding scenarios (i.e. 4C) seem to constrain all the creativity components. Overall, adding creative players mostly impacts the team's collective behaviour rather than the players' creativity-related skills.

Quantifying Exposure and Intra-Individual Reliability of High-Speed and Sprint Running During Sided-Games Training in Soccer Players: A Systematic Review and Meta-analysis

BACKGROUND

Sided games (i.e., small sided, medium sided, large sided) involve tactical, technical, physical, and psychological elements and are commonly implemented in soccer training. Although soccer sided-games research is plentiful, a meta-analytical synthesis of external load exposure during sided games is lacking.

OBJECTIVE

The objective of this systematic review and meta-analysis was to: (1) synthesize the evidence on high-speed and sprint running exposure induced by sided games in adult soccer players, (2) establish pooled estimates and intra-individual reliability for high-speed and sprint running exposure, and (3) explore the moderating effects of game format and playing constraints.

METHODS

A literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. Four databases (PubMed/MEDLINE, Scopus, SPORTDiscus, Web of Science Core Collection) were systematically searched up to 25 January, 2022. Eligibility criteria were adult soccer players (population); training programs incorporating sided games (intervention); game manipulations including number of players, pitch dimension, and game orientation (comparator); and high-speed, very high-speed, and sprint relative (m[Formula: see text]min^-1) running distances and associated intra-individual reliability (outcome). Eligible study risk of bias was evaluated using RoBANS. Pooled estimates for high-speed and sprint running exposure, and their intra-individual reliability, along with the moderating effect of tracking device running velocity thresholds, pitch dimension (i.e., area per player), and game orientation (i.e. score or possession), were determined via a multi-level mixed-effects meta-analysis. Estimate uncertainty is presented as 95% compatibility intervals (CIs) with the likely range of relative distances in similar future studies determined via 95% prediction intervals.

RESULTS

A total of 104 and 7 studies met our eligibility criteria for the main and reliability analyses, respectively. The range of relative distances covered across small-sided games, medium-sided games, and large-sided games was 14.8 m[Formula: see text]min^-1 (95% CI 12.3-17.4) to 17.2 m[Formula: see text]min^-1 (95% CI 13.5-20.8) for high-speed running, 2.7 m[Formula: see text]min^-1 (95% CI 1.8-3.5) to 3.6 m[Formula: see text]min^-1 (95% CI 2.3-4.8) for very high-speed running, and 0.2 m[Formula: see text]min^-1 (95% CI 0.1-0.4) to 0.7 m[Formula: see text]min^-1 (95% CI 0.5-0.9) for sprinting. Across different game formats, 95% prediction intervals showed future exposure for high-speed, very high-speed running, and sprinting to be 0-46.5 m[Formula: see text]min^-1, 0-14.2 m[Formula: see text]min^-1, and 0-2.6 m[Formula: see text]min^-1, respectively. High-speed, very high-speed running, and sprinting showed poor reliability with a pooled coefficient of variation of 22.8% with distances being moderated by device speed thresholds, pitch dimension, and game orientation.

CONCLUSIONS

This review is the first to provide a detailed synthesis of exposure and intra-individual reliability of high-speed and sprint running during soccer sided games. Our estimates, along with the moderating influence of common programming variables such as velocity thresholds, area per player, and game orientation should be considered for informed planning of small-sided games, medium-sided games, and large-sided games soccer training.

CLINICAL TRIAL REGISTRATION

Open Science Framework available through https://osf.io/a4xr2/ .

Comparison of the Physical Response During Official Matches and Small-Sided Games in International Cerebral Palsy Footballers: Implications for Evidence-Based Classification

This study aimed to analyze whether there are differences and associations in the physical responses in international-level cerebral palsy footballers between official matches and 2v2 small-sided games (2v2-SSG). One hundred seventy international cerebral palsy footballers participated in this study during three international championships. The physical responses of mean and maximum velocities, total distance, distance covered at different intensities, short-term actions, and player load were collected during 2v2-SSG and the real competition. The mean velocity, total distance, jogging, medium- and high-intensity distances, the number of moderate/high accelerations, decelerations, and player load were relatively higher in the 2v2-SSG than in the official matches. Even though the 2v2-SSG could become an appropriate drill to include during the classification process, due to the differences between a 2v2-SSG and the official competition, it is necessary to deepen the scientific knowledge for developing observation methods during real competition to strengthen the relationships between eligible impairments and activity limitation.

Integrating physical and tactical factors in football using positional data: a systematic review

Background

Positional data have been used to capture physical and tactical factors in football, however current research is now looking to apply spatiotemporal parameters from an integrative perspective. Thus, the aim of this article was to systematically review the published articles that integrate physical and tactical variables in football using positional data.

Methods and Materials

Following the Preferred Reporting Item for Systematic Reviews and Meta-analyses (PRISMA), a systematic search of relevant English-language articles was performed from earliest record to August 2021. The methodological quality of the studies was evaluated using the modified Downs and Black Quality Index (observational and cross-sectional studies) and the Physiotherapy Evidence Database (PEDro) scale (intervention studies).

Results

The literature search returned 982 articles (WoS = 495; PubMed = 232 and SportDiscus = 255). After screening, 26 full-text articles met the inclusion criteria and data extraction was conducted. All studies considered the integration of physical and tactical variables in football using positional data (n = 26). Other dimensions were also reported, such as psychophysiological and technical factors, however the results of these approaches were not the focus of the analysis (n = 5). Quasi-experimental approaches considered training sets (n = 20) and match contexts (n = 6). One study analysed both training and play insights. Small sided-games (SSG) were the most common training task formats in the reviewed studies, with only three articles addressing medium-sided (MSG) (n = 1) and large-sided games (LSG) (n = 2), respectively.

Conclusions

Among the current systematic review, the physical data can be integrated by player's movement speed. Positional datasets can be computed by spatial movement, complex indexes, playing areas, intra-team and inter-team dyads. Futures researches should consider applying positional data in women's football environments and explore the representativeness of the MSG and LSG.

Impact of absent crowds on technical and physical performances in the Chinese Soccer Super League

Purpose

Spectators have a significant impact on match performances in soccer, but to what extent crowd support contributes to the technical and physical performances remains unclear. This study aimed to (1) investigate the differences in terms of technical and physical performances with and without spectators; and (2) identify the key factors differentiating between win and loss when playing with and without the presence of an audience.

Methods

Our study examined 794 performance records from 397 matches during the 2019-2020 seasons in the Chinese Soccer Super League. The least absolute shrinkage and selection operator (LASSO)-logistic regression was utilized to select significant predictors. Using an independent t-test and the Mann-Whitney non-parametric test explores the difference between matches with and without spectators. Key factors between win and loss were explored using univariate and multivariate logistic regression analyses.

Results

Our study found that cross (p < 0.01, ES = -0.24), shots (p < 0.001, ES = -0.25), and shot accuracy (p < 0.05, ES = -0.18) displayed decreasing trends whereas sprint distances (p < 0.05, ES = 0.16) presented an increasing trend without spectators comparing with the crowd support. Moreover, the above three technical variables were the main factors differentiating between wins and losses. Similarly, team and opponent quality remained important potential factors affecting the match outcome.

Conclusion

Match outcome or team performance is determined by a myriad of factors, but there are clear differences in technical and physical performances between matches with and without the presence of an audience. Similarly, our study provides a better explanation for the impact of crowd support on match performances whereby coaches can deploy players and adjust match strategies for ultimate success.

Visual occlusion effects on youth football players’ performance during small-sided games

This study aimed to explore how youth players’ physical, technical and positional performance may be affected by visual occlusion when playing under different SSG pitch sizes. Under-15 players performed two experimental scenarios: a) normal situation, without visual occlusion; b) visual occlusion, by using an eye patch in the eye corresponding to the dominant foot. These scenarios were tested in a small (40x30m) and a larger pitch (50x35m). Players’ positional data was used to compute tactical and time-motion variables. In addition, technical analysis was comprised using video footage. Playing with visual occlusion in the larger pitch size induced higher distance covered while walking but lower running distance (p < .05). Although no statistically significant effects were identified between the normal and visual occlusion conditions for the tactical behaviour and technical performance a lower number of successful passes (small to moderate effect sizes) and higher regularity in the distance to the opponent’s team centroid (moderate effect size) were found with visual occlusion. Players covered more distance and achieved higher maximum speed in the larger compared to the small pitch (moderate to large effect size, p < .05), while also increasing their distance to both team’s centroid and increasing the regularity to these distances (moderate to large effect size, p < .05). Overall, despite similar effects for tactical and technical variables, some important practical information can be depicted. Accordingly, coaches may use the visual occlusion to promote more stable and regular behaviors while decreasing the physical demands. Larger pitches may be used to increase the distance between players’ and teams, as well as to induce higher physical load in both the normal and visual occlusion conditions. From the technical perspective, coaches may design smaller pitches to emphasize the use of the non-dominant foot during the occlusion scenario and promote the pass during the normal scenario.

Capturing and Quantifying Tactical Behaviors in Small-Sided and Conditioned Games in Soccer: A Systematic Review

Purpose: To systematically describe and analyze the tracking systems, the variables, and the statistical methods used to evaluate the players and teams' tactical behavior in small-sided and conditioned games (SSCGs). Methods: A search was done in Web of Science, PubMed, Science Direct, and Scielo databases to identify manuscripts published between 2008 and 2019 that manipulated small-sided and conditioned games (SSCGs) and analyzed tactical behaviors of players and teams. Results: From 349 articles identified, 31 were selected for review. To collect positional data, the global positioning system (GPS), the local position measurement (LPM) system, and TACTO were identified as reliable tracking systems. Twenty-one positional variables were identified to evaluate tactical behaviors, grouped into five main categories: team balance, playing space, width and length of playing space, and interpersonal distance. Tactical behavior patterns were analyzed using approximate entropy, sample entropy, Shannon entropy, and patterns of coordination between players and teams were analyzed using relative phase and running correlation. Discussion: The tracking systems analyzed were reliable but revealed different advantages and disadvantages of their use. Authors should define the use of each tracking system based on their purpose and level of precision required for analysis. A great duplication was observed on the variables used with similar purposes of tactical analysis. The identification of the variables according to their purpose of analysis will allow a better understanding of their use in the future.

Amplifying perceptual demands: How changes in the colour vests affect youth players performance during medium-sided games

This study explored how manipulating the colour of training vests affects footballers' individual and collective performance during a Gk+6vs6+Gk medium-sided game. A total of 21 under-17 years old players were involved in three experimental conditions in a random order for a total of four days: i) CONTROL, two teams using two different colour vests; ii) SAME, both teams wearing blue vests; iii) MIXED, all 6 players per team wore different colour vests. Players' positional data was used to compute time-motion and tactical-related variables, while video analysis was used to collect technical variables. Further, these variables were synchronized with spatiotemporal data allowing to capture ball-related actions in a horizontal 2D plan. All variables were analysed from the offensive and defensive perspective. From the offensive perspective, players performed more and further shots to goal during the CONTROL than in SAME and MIXED (small effects) conditions, with a decreased distance to the nearest defender (small effects). While defending, results revealed lower distance to the nearest teammate (small effects) in the CONTROL than in the SAME and MIXED conditions, and higher team longitudinal synchronization (small effects). In addition, the CONTROL showed in general lower values of team width while defending than in the other 2 conditions. Overall, coaches may use the CONTROL condition to emphasize offensive performance and defensive behaviour over the longitudinal direction with increased physical demands. In turn, coaches may use the manipulation of players vests to emphasize defensive performance, as players seem to behave more cohesively under such scenarios.

Reference values for collective tactical behaviours based on positional data in professional football matches: a systematic review

Match collective tactical behaviours can be used as a reference to design and select training strategies to improve individual and team performance in professional football. The aim of the systematic review was to cluster the collective tactical variables used to highlight and compare male soccer teams’ collective behaviour during professional official matches, providing reference values for each of them. A systematic review of relevant articles was carried out using three electronic databases (PubMed, SPORTdiscus and Web of Science). From a total of 1,187 studies initially found, 13 original articles were included in the qualitative synthesis. The articles found concerned studies carried out on the Spanish, Portuguese, English and Brazilian 1^st divisions and during the European UEFA Champions League. The team length and width ranged from 31 to 46 m and from 35 to 48 m, respectively. The distance from a defending team’s goalkeeper to the nearest teammate ranged from 9 ± 6 to 30 ± 7 m, the goal line-recovery location from 27 to 37 m, and the opponent’s goal line from 42 to 50 m. The stretch index ranged from 7 to 16 m. Mean team area was ~900 m² and the area of the pitch which included all outfield players divided by the 20 outfield players ranged from 79 ± 15 to 94 ± 16 m². All studies provided greater distance and area values during the team-possession phase in comparison to the non-possession one. The ball location on the pitch determined the collective tactical behaviour of the teams. The differences between halves in the distance and area values were contradictory. Further studies should assess the effect of the interaction between the contextual factors on the collective tactical behaviour to obtain more accurate references. This could help football coaches in the design of suitable training tasks to optimize tactical performance.

Efecto de la orientación de las tareas de entrenamiento en fútbol femenino

El objetivo de este estudio ha sido analizar si la modificación de las tareas de entrenamiento, en concreto la orientación del espacio, tiene consecuencias en los diferentes parámetros que identifican la carga de trabajo en el fútbol femenino. En el estudio participaron 18 jugadoras de fútbol femenino (M = 21.89; DT = 6.20), que realizaron dos sesiones con cuatro tareas cada una. Las tareas estaban contrabalanceadas para cada sesión para evitar el efecto del orden de las mismas. Se utilizaron GPS Polar Team Pro para medir la carga física y cuestionarios para la carga mental. Para comparar los resultados de cada sesión se llevó a cabo una prueba T de medidas relacionadas. Los resultados muestran que la carga física fue mayor en las tareas donde no hubo orientación, al igual que la carga mental. Por tanto, el espacio en el que se desarrollan las tareas de entrenamiento resulta determinante en la carga mental percibida en fútbol femenino.

Match Analysis of Soccer Refereeing Using Spatiotemporal Data: A Case Study

This case study explored how spatiotemporal data can develop key metrics to evaluate and understand elite soccer referees’ performance during one elite soccer match. The dynamic position of players from both teams, the ball and three elite referees allowed to capture the following performance metrics: (i) assistant referees: alignment with the second last defender; (ii) referee: referee diagonal movement—a position density was computed and a principal component analysis was carried to identify the directions of greatest variability; and (iii) referee: assessing the distance from the referee to the ball. All computations were processed when the ball was in-play and separated by 1st and 2nd halves. The first metric showed an alignment lower than 1 m between the assistant referee and the second last defender. The second metric showed that in the 1st half, the referee position ellipsis area was 548 m², which increased during the 2nd half (671 m²). The third metric showed an increase in the distance from the referee to the ball and >80% of the distance between 5–30 m during the 2nd half. The findings may be used as a starting point to elaborate normative behavior models from the referee’s movement performance in soccer.

Identification, Computational Examination, Critical Assessment and Future Considerations of Spatial Tactical Variables to Assess the Use of Space in Team Sports by Positional Data: A Systematic Review

The aim of the review was to identify the spatial tactical variables used to assess the use of space in team sports using positional data. In addition, we examined computational methods, performed a critical assessment and suggested future considerations. We considered four electronic databases. A total of 3973 documents were initially retrieved and only 15 articles suggested original spatial variables or different computation methods. Spatial team sport tactical variables can be classified into 3 principal types: occupied space, total field coverage by several players; exploration space, the mean location (±standard deviations in X- and Y-directions) of the player/team during the entire game; and dominant/influence space, the region the players can reach before any other players. Most of the studies, i.e., 55%, did not include goalkeepers (GKs) and total playing space to assess occupied space, however, several proposed new variables that considered that all playing space could be “played” (i.e. effective free-space, normalized surface area). Only a collective exploration space variable has been suggested: the major range of the geometrical centre (GC). This suggestion could be applied to assess collective exploration space variables at a sub-system level. The measurement of the dominant/influence space has been based on the Voronoi region (i.e. distance d criteria), but several studies also based their computation on the time (t). In addition, several weighted dominant areas have been suggested. In conclusion, the use of spatial collective tactical variables considering the principal structural traits of each team sport (e.g. players of both teams, the location of the space with respect to the goal, and the total playing space) is recommended.

How Numerical Unbalance Constraints Physical and Tactical Individual Demands of Ball Possession Small-Sided Soccer Games

This study aimed to explore the effects of playing different unbalanced ball possession small-sided games on external workload (distance covered while walking, running, and sprinting, and max speed), tactical individual actions (number of passes with dominant and non-dominant foot), and internal load (rating of perceived exertion, RPE) in under-23 soccer players. Participants played 4v2, 4v3, 4v4, 4v5, and 4v6 small-sided games (SSGs) on a 30 × 25 m playing area. Data were analyzed under an opponent-based perspective, by fixing one team (4vX), and by cooperation-based perspective according to teammates (4v2+X). Global Position System (GPS) monitors were used to collect and compute external workloads and individual tactical actions, and Borg Scale CR10 was used to evaluate RPE. High-Superiority (4v2), Superiority (4v3), and Very Low-Cooperation (4v2+0) formats allow players in balanced teams to cover more distance while walking; on the other side, Inferiority (4v5), High-Inferiority (4v6), and Very High-Cooperation (4v2+4) allow players to sprint more and practice more tactical individual actions as a resultant emergent behavior; all players in SSG conditions with a lower number of conditions, perceived the exercise as more intense, especially in situations with less than two players. Overall, playing in high inferiority situations (4v2 and 4v6) may be used to increase physical demand for the outnumbered team, while coaches may use low superiority situations to adjust the task complexity when developing the players’ tactical individual actions.

Identification, Computational Examination, Critical Assessment and Future Considerations of Distance Variables to Assess Collective Tactical Behaviour in Team Invasion Sports by Positional Data: A Systematic Review

The aim of the study was the identification, computational examination, critical assessment and future considerations of distance variables to assess collective tactical behaviour in team invasion sports by positional data. A total of 3973 documents were initially retrieved. Finally, 72 articles met the inclusion criteria, but only 26 suggested original tactical variables based on the distance variables. The distance variables can be classified into player–player, player–space, player–ball, and Geometrical Centre (GC)–GC /player/space/goal. In addition, several nonlinear techniques have been used to analyse the synchronisation and predictability of the distance variables in team invasion sports. Player–opponent distance is of special interest in those sports in which man-marking is commonly used, and in the micro-structure close to scoring situations in all sports. In addition, player–player distances are used to measure the length and the width of the team and player–GC distance to assess the dispersion of the team. Player–space distances have been measured to assess the distance of the player/team-line to relevant areas of the playing space. Several techniques have been applied to analyse the synchronisation (i.e., Hilbert transformation and cluster analyses) and the complexity and regularity or predictability (i.e., approximate entropies, sample entropy, cross-sample entropy and average mutual information) of the distance variables in team invasion sports, revealing the lack of consensus. Although the distance variables may be interesting tactical variables when considered in isolation, it would be enriching to analyse the relationship among these variables.

Effects of Temporary Numerical Imbalances on Collective Exploratory Behavior of Young and Professional Football Players

The aim of this study was to explore how the use of temporary numerical imbalances during small-sided Game SSGs affects team’s exploratory behaviors (i.e., variety and quantity of responses given in an ever-changing game context and its rate of change) in different age groups. Two different age groups (under−15 and under−23) of football players participated in the study. For each age group, three teams of five players played six small-sided games of 5 min duration in different conditions: (i) numerical balance (GK + 4 vs. 4 + GK); (ii) temporary numerical imbalance, which consisted of a numerical change of teammates and opponents every one minute. Latitude and longitude GPS coordinates were used to determine the positioning-derived variables. The dynamic overlap (i.e. the measure of average similarity of the game patterns that take place in increasingly larger time intervals) was used to provide information of the rate and breadth of exploratory behavior. The results revealed that the long-term exploratory breadth increased for the under−23 age group. Non-clear effects were found for the short-term rate of exploration, but with an increasing trend. In the under−15 group, the exploratory behavior was more likely to increase in the long term. The increase for the short-term rate of exploration was unclear, but it follows an increasing trend. These results suggest that the use of temporary numerical imbalances could offer coaches more dynamic training situations and different adaptive training environments similar to matches.

Effects of the pitch configuration design on players' physical performance and movement behaviour during soccer small-sided games

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.