Interpersonal coordination and ball dynamics in futsal (indoor football)

Analysis of player speed and angle toward the ball in soccer

The study analyzes how the magnitude and angle of the speed of soccer players change according to the distance to the ball and the phases of the game, namely the defensive and attacking phases. We observed how the role played in the team (goalkeeper, defender, midfielder, or forward) strongly determines the speed pattern of players. As a general trend, the speed's modulus is incremented as their position is closer to the ball, however, it is slightly decreased when arriving at it. Next, we studied how the angle of the speed with the direction to the ball is related to the distance to the ball and the game phases. We observed that, during the defensive phase, goalkeepers are the players that run more parallel to the ball, while forwards are the ones running more directly to the ball position. Importantly, this behavior changes dramatically during the attacking phase. Finally, we show how the proposed methodology can be used to analyze the speed-angle patterns of specific players to understand better how they move on the pitch according to the distance to the ball.

Interpersonal coordination analysis in bat-and-ball sports under a real game situation: Asymmetric interaction and delayed coupling

This study investigated the interpersonal coordination between the pitcher and the batter in bat-and-ball sports. Although the importance of interpersonal coordination is widely accepted in many sports, no studies have investigated it in bat-and-ball sports because the dominant task constraints surrounding the interaction between pitcher and batter make it difficult to apply conventional analytic techniques. To address the issue, this study proposes a new analytical framework to investigate interpersonal coordination in bat-and-ball sports under a real game situation with two main characteristics: asymmetric interaction and delayed coupling. First, the dynamic time warping technique was used to evaluate the stability of the head movement pattern of the pitcher and batter, and cross-correlation analysis was used to quantify the temporal relationship between them. We found that the head movement pattern of batters was significantly more unstable than that of pitchers, and approximately 60% of the variance of the change in the head movement pattern of batters could be explained by that of the pitchers. Moreover, expert batters followed a pitcher's movements with a specific time delay of approximately 250 ms. These findings highlight the characteristics of interpersonal coordination in bat-and-ball sports: the pitcher can make a pre-patterned stable motion, whereas the batter needs to follow and adjust their movement to it. Although the effects of prediction ability need to be investigated to understand its detailed mechanism, the contribution of this study is that it revealed the existence of the interpersonal coordination between the pitcher and batter of bat-and-ball sports under a real game situation.

Interpersonal coordination tendencies and perception of visual information for decision-making in futsal

This study investigated how futsal players visually perceived information on angular interpersonal coordination relations, between available sources such as nearest defender, goalkeeper position and ball, when deciding to shoot at goal. Experienced players (n = 180) participated in eighteen, video-recorded futsal matches, during which 32 participants wore an eye tracking device. Forty-five sequences of play were selected and edited from the moment a teammate passed the ball to the shooter, until the moment a shot was undertaken. Independent variables included the angle connecting the shooter to their closest defender and goalkeeper, and it's rate of change (velocity and variability) during performance. Then eye tracking system (TOBII PRO) was used to examine gaze patterns of shooters during task performance. Findings revealed that: (i) futsal players adapted their gaze patterns differently between key information sources when shooting confirmed as: their closest defender, goalkeeper, ball, and court floor; and (ii), the ball was the information source which was most fixated on, regardless of the characteristics of interpersonal coordination tendencies that emerged when shooting. These findings can be interpreted as evidence of functional perceptual behaviours used to regulate actions needed to ensure precise contact with the ball when shooting at goal. Further, adaptations of fixation patterns, varied between marking defender, goalkeeper, and ball, may provide functional postural orientation to facilitate a successful shot at goal.

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.

Strength and Power Performance Changes During an In-Season Resistance Training Program in Elite Futsal Players: A Case Study

In this study, we aimed to analyze (i) the strength and power changes after resistance training (RT) in elite futsal players, and (ii) the associations between the session rate of perceived exertion (sRPE) and perceived total quality recovery (TQR), and the sRPE and TQR with the volume load of the RT program. Ten elite futsal players (24.8 ± 5.4 years; 76.2 ± 7.1 kg; 1.77 ± 0.05 m) performed an in-season 8-week RT program twice per week. RT consisted of 2-3 sets x 3-6 reps at 45-65% of one-repetition maximum (1RM) with maximal velocities in the full squat and complementary exercises with the same volume. We assessed the TQR before every session, while the sRPE was calculated after each RT session. One week before and after the intervention, we measured the countermovement jump (CMJ) height, isometric hip adduction strength (IHAS), 1RM, and peak power (PP) in the full squat progressive loading test. After the 8-week training program, there was a significant improvement in most outcomes, yet the gains (%Δ) remained below the minimal detectable change (MDC), except for IHAS (CMJ: p < 0.05, %Δ = 6.7, MDC% = 7.2; IHAS: p < 0.001, %Δ = 19.1, MDC% = 14.6; 1RM: p > 0.05, %Δ = 9.2, MDC% = 21.5; PP: p < 0.05; %Δ = 14.4, MDC% = 22.4). We also found a significant negative correlation between TQR and the sRPE (r = -0.45, p < 0.001). Our data suggest that RT based on low-volume and low-to-moderate loads may not produce a sufficient stimulus to induce meaningful dynamic strength and power gains in elite futsal players, although it improves isometric strength. Furthermore, monitoring TQR before sessions may show coaches how the elite futsal player will perceive the session's intensity.

Integração entre a análise do desempenho e o ensino-aprendizagem nos esportes coletivos

RESUMO Nos esportes coletivos, a análise do desempenho e a condução do processo de ensino-aprendizagem implicam, implícita ou explicitamente, escolhas metodológicas. Neste trabalho, serão apresentadas algumas das principais abordagens teórico-metodológicas que embasam a análise do desempenho e o ensino-aprendizagem nos esportes coletivos e suas implicações práticas. Será discutida a integração desses conteúdos com o intuito de contribuir com o suporte científico para a prática pedagógica do professor/treinador.

Lateral Preference and Inter-limb Asymmetry in Completing Technical Tasks During Official Professional Futsal Matches: The Role of Playing Position and Opponent Quality

This study had the purpose of analyzing dominant and non-dominant limb performances (frequency of use and accuracy) during match-play technical actions with ball possession (receiving, passing, and shooting a ball) in professional futsal and also check for the possible influence of playing position and the quality of opponent. We have analyzed data pertaining to eight matches of the FIFA Futsal World Cup Thailand 2012™ in which 76 male professional senior futsal players participated (44 right-footed and 32 left-footed). In total, we coded 5,856 actions (2,550 ball receptions, 3,076 passes, and 230 shoots). Our main findings were that (a) players used the dominant limb more frequently than the non-dominant limb for all actions considered [p < 0.001; effect size (ES) medium-to-large]; (b) accuracy was generally greater when using the dominant limb, regardless of the quality of opponent (p < 0.01; ES large); and (c) in shooting actions, pivots showed similar accuracy between dominant and non-dominant limbs (p = 0.51; ES small). The study suggested that when completing technical actions with the ball in futsal, high-level players depended to a greater extent on the use of their dominant lower limb during official matches. Excepting a similarity detected between limbs on shooting performance of pivots, players from all positional roles generally showed a higher accuracy rate in receiving, passing, and shooting a ball when using their dominant limb as compared to their non-dominant one during match-play and the limb usage and accuracy seemed to be independent of the quality of opponents.

How Informational Constraints for Decision-Making on Passing, Dribbling and Shooting Change With the Manipulation of Small-Sided Games Changes in Futsal

In this study, we explored how manipulating floaters' positions in small-sided futsal games (SSGs) promote changes in the informational constraints that support decision-making (DM) for passing, dribbling and shooting tactics. We made changes in four experimental 3 vs 3 small-sided game conditions with 30 male futsal players (U19 age category): (a) Floaters Off (FO), (b) Final Line Floaters (FLF), (c) Lateral Floaters own field sideline (LFofsl) and (d) Lateral Floaters full field sideline (LFffsl). We assessed players' activity with WIMU PRO™ software during the SSGs, using the Game Performance Evaluation Tool (GPET) to analyze a total of 1,635 decisions. DM for dribbling was generally based on the interpersonal distance between the ball carrier and direct opponent, considering the defensive team length and the offensive team area. Shooting decisions were constrained, by certain attacking-defending teams' spatial-temporal relations with regard to playing space and team balance as affected by manipulating floaters' positions. The coaches' decisions to change the floaters' positions during SSGs may change informational variables sustaining the dribbling decision, but no changes in SSG variables affected passing DM.

Identification of the Patterns Produced in the Offensive Sequences That End in a Goal in European Futsal

Victory is the ultimate aim in high performance sports; when it comes to team sports, the goal is the key that allows players to achieve that victory. This is the case with futsal which, due to its internal structure as well as the speed in the development of its game, makes the achievement of a goal not an isolated event, but rather more than one goal must be scored to achieve victory. The aim of the present study is to analyze the construction of offensive sequences that have resulted in goal-scoring in the two main European futsal leagues, the Spanish and the Italian, as well as to identify the patterns relating to offensive actions that have ended with a goal being scored. Observational methodology was used to develop the research and an ad hoc observation instrument (OAF-I) was developed for this purpose. The data was analyzed using inferential statistics as well as sequential analysis of delays in a diachronic analysis to identify the patterns of offensive actions. The results obtained enable recognition of a league’s idiosyncrasy patterns in goal-scoring in each of the leagues studied. The results obtained will allow experts to have a better understanding of how goals are scored and how to establish more specific training tasks, in both attack and defense.

Development of Defensive Actions in Small-Sided and Conditioned Games With Offensive Purposes in Futsal

Based on ecological dynamics approach, non-linear pedagogy (NLP) have emerged with the goal of promoting a holistic approach through the use of small-sided and conditioned games (SSCGs), to optimize specific tactical defensive and offensive behaviors of players. This study analyzed the indirect effects of an intervention program, based on NLP (task design based on tactical principles of attack and numerical advantage of attacking team), in decision-making (DM) and execution (Ex) in defensive technical–tactical actions in U16 futsal. Eight futsal players (U16 years) participated in 12 training sessions, spread over two phases: preintervention and intervention. The Game Performance Evaluation Tool (GPET) instrument was used to analyze the DM and Ex of 2,600 defensive actions measured during competitive matches. Results showed significant improvements in marking actions (to the player with the ball: DM, p = 0.001; Ex, p = 0.001; and to the player without the ball: DM, p = 0.039; Ex, p = 0.046), improvements in blocking actions (DM, p = 0.015), and improvements in help-coverage actions (Ex, p = 0.014). No significant differences were found in the interception and tackling actions. This study has shown evidence that the NLP approach is an appropriate theoretical framework to enhance acquisition of defensive tactical behavior in futsal. However, not all actions improved. Therefore, coaches should design representative tasks to optimally develop technical–tactical training processes based on the phases of futsal game (offensive and defensive) and considering the level of opposition.

A systematic review of collective tactical behaviour in futsal using positional data

Although many studies on collective tactical behaviour have been published in the last decade, no study has revised and summarized the findings provided for futsal. The main aim of this systematic review was to identify and discuss the geometrical centre (GC), distance and area tactical variables used to assess team behaviour in futsal. In addition, it summarizes the findings on the tactical response during futsal competition and training. A systematic review of the relevant articles provided on futsal was carried out using seven electronic databases (SPORTDiscus, ProQuest, Cochrane Plus, Scopus, Google Scholar, PubMed and Web of Science) until September 25, 2019. From a total of 1,209 studies initially found, 12 were included in the qualitative synthesis. There were some trends in the analysis of positional data in futsal with the most relevant situations analysed being 1 vs 1 and 5 vs 4+Goalkeeper. The distances and angles between two points were the most assessed tactical variables. Five types of distance variables were used to assess collective tactical behaviour in futsal: GC-GC, GC-player, player-player, player-ball and player-space. Pressure (GC-GC) was greater in shots on goal than in tackles during professional futsal matches. Area variables were reduced to occupied space, exploration space and dominant area. Occupied space was measured only during competition while the dominant area was measured only during training sessions. The surface area and dominant regions were greater when players were attacking in comparison to when they were defending. In addition, two non-linear techniques (i.e. relative phase and entropy) were applied to analyse synchronisation and complexity and regularity or predictability. Defenders were highly synchronous, while attackers tried to break this coordination to achieve possibilities for action. Task constraints are suitable to induce different regularity patterns. This review is an opportunity to develop studies aimed at bridging the gap in collective tactical behaviour in futsal.

The Influence of Functional Flywheel Resistance Training on Movement Variability and Movement Velocity in Elite Rugby Players

The aim of this study was to identify the changes in movement variability and movement velocity during a six-week training period using a resistance horizontal forward-backward task without (NOBALL) or with (BALL) the constraint of catching and throwing a rugby ball in the forward phase. Eleven elite male rugby union players (mean ± SD: age 25.5 ± 2.0 years, height 1.83 ± 0.06 m, body mass 95 ± 18 kg, rugby practice 14 ± 3 years) performed eight repetitions of NOBALL and BALL conditions once a week in a rotational flywheel device. Velocity was recorded by an attached rotary encoder while acceleration data were used to calculate sample entropy (SampEn), multiscale entropy, and the complexity index. SampEn showed no significant decrease for NOBALL (ES = -0.64 ± 1.02) and significant decrease for BALL (ES = -1.71 ± 1.16; p < 0.007) conditions. Additionally, movement velocity showed a significant increase for NOBALL (ES = 1.02 ± 1.05; p < 0.047) and significant increase for BALL (ES = 1.25 ± 1.08; p < 0.025) between weeks 1 and 6. The complexity index showed higher levels of complexity in the BALL condition, specifically in the first three weeks. Movement velocity and complex dynamics were adapted to the constraints of the task after a four-week training period. Entropy measures seem a promising processing signal technique to identify when these exercise tasks should be changed.

Early warning signals in motion inference

The ability to infer intention lies at the basis of many social interactions played out via motor actions. We consider a simple paradigm of this ability in humans using data from experiments simulating an antagonistic game between an Attacker and a Blocker. Evidence shows early inference of an Attacker move by as much as 100ms but the nature of the informational cues signaling the impending move remains unknown. We show that the transition to action has the hallmark of a critical transition that is accompanied by early warning signals. These early warning signals occur as much as 130 ms before motion ensues-showing a sharp rise in motion autocorrelation at lag-1 and a sharp rise in the autocorrelation decay time. The early warning signals further correlate strongly with Blocker response times. We analyze the variance of the motion near the point of transition and find that it diverges in a manner consistent with the dynamics of a fold-transition. To test if humans can recognize and act upon these early warning signals, we simulate the dynamics of fold-transition events and ask people to recognize the onset of directional motion: participants react faster to fold-transition dynamics than to its uncorrelated counterpart. Together, our findings suggest that people can recognize the intent and onset of motion by inferring its early warning signals.

Variability in tactical behavior of futsal teams from different categories

The aim of the present study was to analyze the time series of team spread during futsal official matches in the frequency domain for different categories. Using an automatic tracking method, trajectories of 258 players (excluding goalkeepers) were obtained, composed of 79 players from the under-15 (U15) category, 86 from the under-18 (U18), and 93 from the professional. We calculated the team spread defined as the Euclidean norm of the distance-between-player vector as a function of time. We applied the Fast Fourier Transformation method and calculated the median frequency for each time series of spread. The results of mean ± SD of the median frequency of the time series of spread from the first to the second half were significantly different only for the U15 category (first half, 1.04 ± 0.46, second half 1.40 ± 0.34). The frequency values differed significantly between the categories. The younger categories presented a higher frequency of spread oscillation than the professional category, which reflects the dynamics of the game between attack and defense sequences. The results provide insights into the features of the sport and present a basis for appropriate training interventions for players in each category, planning for future transition to the following category.

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.

Goals scored and received in 5vs4 GK game strategy are constrained by critical moment and situational variables in elite futsal

The aim of this study was to identify the importance and meaning of goals using the goalkeeper as an outfield player in elite futsal according to critical and situational variables. The sample consisted of 11,446 actions corresponding to 1,325 matches from the 1^st division Spanish Futsal League during the seasons from 2010 to 2015. Multinomial logistic regression and classification tree multivariate models were used to identify the best predictor variables related to the likelihood of scoring goals, receiving goals, or no goals. Results from Multinomial logistic regression emphasised goals scored in balanced matches and playing with the goalkeeper as an outfield player before the last eight minutes. When the teams were drawing or losing, finished with goals received or without goals. The classification tree results identified a greater likelihood of scoring goals when the teams were winning, in balanced matches, and within the last eight minutes. Conversely, a greater likelihood of suffering goals was observed using the goalkeeper as an outfield player when the teams were losing, in unbalanced matches and in the last eight minutes. The identified trends will allow futsal coaches to recognise the most suitable situations for achieving efficacy when using the goalkeeper as an outfield player strategy.

Attacking Profiles of the Best Ranked Teams From Elite Futsal Leagues

This study aimed to (i) explore the discriminatory power of the task-related variables and the context in establishing differences in the elite futsal leagues of Portugal, Spain, and Russia and (ii) understand how these variables vary according to the match outcome. Methodological issues concerning efficiency (goals and shots), offensive organisation (positional attack, counterattack, set pieces, or 5vs4+Goalkeeper), 1st goal scored during matches (home or away team), match type (balanced or unbalanced), and match outcome (winner, loser, or drawer) were discussed. Archival data were obtained from the 2017–2018 season of Portuguese, Spanish, and Russian professional futsal leagues for all play-off matches. Crosstabs analysis was conducted to establish the significance relationship between the elite futsal leagues and the situational variables. Afterward, discriminant analysis was used to identify the task-related variables that maximise mean differences between different league teams for defining offensive profile, and the variations found when the condition of the winner, loser, or drawer is taken into account. The results allowed to understand that the Portuguese and Russian teams used the positional attacks more, and less the counterattacks and set pieces than the Spaniards, who present a more balanced offensive profile. Overall, winners were better discriminated by goals scored, whereas 5vs4+Goalkeeper strategy discriminated loser teams. Coaches should be aware of these different offensive profiles in order to increase control over the match planning and decrease predictability against opposing teams.

Effects of Low-Moderate Load High-Velocity Resistance Training on Physical Performance of Under-20 Futsal Players

Resistance training (RT) is an effective methodology to improve physical performance of athletes. However, up to now, no studies have addressed the RT benefits in under-20 futsal players. The purpose of this study was to evaluate the effects of six weeks of RT with high-velocity movements, low-to-moderate loads, and low volume on physical performance of under-20 futsal players. A total of 21 players were divided into two groups: A control group (CG, n = 10) and a RT group (RTG, n = 11). The RTG performed two weekly training sessions constituted by leg-press, jumps, and sprints, along with three futsal training sessions, while the CG only performed the futsal training. Before and after the intervention, the sprint time in 0–10 m (T₁₀), 10–20 m (T_10–20), and 0–20 m (T₂₀), the countermovement jump (CMJ) height, the T-Test time, the kicking ball speed (KBS), and the maximum dynamic strength in the leg-press, were assessed. In post-test, significant improvements in CMJ, T-Test, KBS, and leg-press were found for the RTG, whilst a significant decrease in T_10–20 was evidenced in the CG. The present results suggested that RT based on high velocity movements, low-to-moderate loads, and low volume produce positive effects on physical performance of under-20 futsal players.

Differences in Physical Performance According to the Competitive Level in Futsal Players

The purpose of the present study was to describe performance in acceleration capacity, change of direction ability, vertical jump, horizontal jump, repeated sprint ability, and endurance (Yo-Yo Intermittent Recovery Test Level 1) in futsal players, and analyze the differences according to competitive categories or levels. The total sample (n = 40) was divided into three groups depending on the category in which the participants competed: Second Division B (n = 15), Third Division (n = 12) and juniors (n = 13). All the tests were performed with participants’ regular competition shoes and on the usual playing surface, in an indoor pavilion with a floating wood floor. The results of the study did not show significant differences in acceleration capacity (5 and 15 m) or change of direction ability among the different categories. In contrast, significant differences were found among the categories with regard to horizontal jump and vertical jump capacity (p < 0.05); but not in all the variables analyzed. Performance in repeat sprint ability varied significantly among the different categories in 30 m (p < 0.01) but not in 5 m (p > 0.05). The distance covered in the Yo-Yo Intermittent Recovery Test Level 1 by the Second Division B and the Third Division groups was greater than that covered by the junior group. In the light of these results repeated sprint ability and aerobic endurance could be two discriminating qualities of the competitive level among different futsal categories.

How do futsal players of different categories play during official matches? A tactical approach to players' organization on the court from positional data

The purpose of this study was to analyze futsal players’ organization on the court in different categories while attacking and defending, in interception and shot to goal situations. We obtained the trajectories of 89 players from the under-15 category, 102 players from the under-18 category, and 110 professional players, during official matches. The spread, surface area, and Euclidian distances between the teams’ centroids were measured to represent the distribution of the futsal players on the court. The variables were analyzed during each offensive and defensive sequence, and during situations of shots to goal and interceptions, with and without the outfield goalkeeper player participation. While the players were attacking, all categories presented greater spread and surface area, compared to values when players were defending (P < 0.01). Among the categories, the results showed lower spread and area values for the younger players (P < 0.01). The results of spread, surface area, and distances between the teams’ centroids showed different forms of organization for each of the categories in specific situations of shots to goal and interceptions. The study provided insights that allow coaches to better plan suitable tactical training according to the requirements of each category.

Coordinated Interpersonal Behaviour in Collective Dance Improvisation: The Aesthetics of Kinaesthetic Togetherness

Collective dance improvisation (e.g., traditional and social dancing, contact improvisation) is a participatory, relational and embodied art form which eschews standard concepts in aesthetics. We present our ongoing research into the mechanisms underlying the lived experience of “togetherness” associated with such practices. Togetherness in collective dance improvisation is kinaesthetic (based on movement and its perception), and so can be simultaneously addressed from the perspective of the performers and the spectators, and be measured. We utilise these multiple levels of description: the first-person, phenomenological level of personal experiences, the third-person description of brain and body activity, and the level of interpersonal dynamics. Here, we describe two of our protocols: a four-person mirror game and a ‘rhythm battle’ dance improvisation score. Using an interpersonal closeness measure after the practice, we correlate subjective sense of individual/group connectedness and observed levels of in-group temporal synchronization. We propose that kinaesthetic togetherness, or interpersonal resonance, is integral to the aesthetic pleasure of the participants and spectators, and that embodied feeling of togetherness might play a role more generally in aesthetic experience in the performing arts.

Influence of stimulus velocity profile on unintentional visuomotor entrainment depends on eye movements

Humans spontaneously entrain their movements to visual rhythms in the environment. Previous research has shown that the strength of such unintentional visuomotor entrainment is enhanced when observing rhythms characterized by the nonlinear, Rayleigh kinematics typical of human movements; such movements are characterized by greater slowness towards the trajectory turning points compared to sinusoidal movements. However, the enhanced unintentional entrainment to rhythms exhibiting Rayleigh kinematics has only been shown to occur when participants tracked stimulus movements with their eyes, which might have facilitated access to important information for enhanced entrainment. The current study compared the strength of unintentional visuomotor entrainment with both Rayleigh and sinusoidal kinematics when participants were either tracking (eye following the oscillating stimulus) or non-tracking (eye fixed at the centre of the stimulus trajectory) stimulus movements. The results showed that enhanced unintentional entrainment with Rayleigh stimuli only occurred with eye-tracking, supporting that slowness of rhythmic movements towards turning points facilitate entrainment and that access to this information depends on eye movements.

Dynamics of tactical behaviour in association football when manipulating players' space of interaction

The analysis of positional data in association football allows the spatial distribution of players during matches to be described in order to improve the understanding of tactical-related constraints on the behavioural dynamics of players. The aim of this study was to identify how players' spatial restrictions affected the exploratory tactical behaviour and constrained the perceptual-motor workspace of players in possession of the ball, as well as inter-player passing interactions. Nineteen professional outfield male players were divided into two teams of 10 and 9 players, respectively. The game was played under three spatial constraints: a) players were not allowed to move out of their allocated zones, except for the player in possession of the ball; b) players were allowed to move to an adjacent zone, and; c) non-specific spatial constraints. Positional data was captured using a 5 Hz interpolated GPS tracking system and used to define the configuration states of players for each second in time. The configuration state comprised 37 categories derived from tactical actions, distance from the nearest opponent, distance from the target and movement speed. Notational analysis of players in possession of the ball allowed the mean time of ball possession and the probabilities of passing the ball between players to be calculated. The results revealed that the players' long-term exploratory behaviour decreased and their short-term exploration increased when restricting their space of interaction. Relaxing players' positional constraints seemed to increase the speed of ball flow dynamics. Allowing players to move to an adjacent sub-area increased the probabilities of interaction with the full-back during play build-up. The instability of the coordinative state defined by being free from opponents when players had the ball possession was an invariant feature under all three task constraints. By allowing players to move to adjacent sub-areas, the coordinative state became highly unstable when the distance from the target decreased. Ball location relative to the scoring zone and interpersonal distance constitute key environmental information that constrains the players' coordinative behaviour. Based on our results, dynamic overlap is presented as a good option to capture tactical performance. Moreover, the selected collective (i.e. relational) variables would allow coaches to identify the effects of training drills on teams and players' behaviour. More research is needed considering these type variables to understand how the manipulation of constraints induce a more stable or flexible dynamical structure of tactical behaviour.

Teams as Complex Adaptive Systems: Reviewing 17 Years of Research

At the turn of the century, Arrow, McGrath, and Berdahl portrayed teams as complex adaptive systems (CAS). And yet, despite broad agreement that this approach facilitates a better understanding of teams, it has only now been timidly incorporated into team research. To help fully incorporate the logic of teams as CAS in the science of teams, we review extant research on teams approached from a nonlinear dynamical system theory. Using a systematic review approach, we selected 92 articles published over the last 17 years to integrate what we know about teams as CAS. Our review reveals the evidence supporting teams as CAS, and the set of analytical techniques to analyze team data from this perspective. This review contributes to teams’ theory and practice by offering ways to identify both research methods and managing techniques that scholars and practitioners may apply to study and manage teams as CAS.

Soft-assembled Multilevel Dynamics of Tactical Behaviors in Soccer

This study aimed to identify the tactical patterns and the timescales of variables during a soccer match, allowing understanding the multilevel organization of tactical behaviors, and to determine the similarity of patterns performed by different groups of teammates during the first and second halves. Positional data from 20 professional male soccer players from the same team were collected using high frequency global positioning systems (5 Hz). Twenty-nine categories of tactical behaviors were determined from eight positioning-derived variables creating multivariate binary (Boolean) time-series matrices. Hierarchical principal component analysis (PCA) was used to identify the multilevel structure of tactical behaviors. The sequential reduction of each set level of principal components revealed a sole principal component as the slowest collective variable, forming the global basin of attraction of tactical patterns during each half of the match. In addition, the mean dwell time of each positioning-derived variable helped to understand the multilevel organization of collective tactical behavior during a soccer match. This approach warrants further investigations to analyze the influence of task constraints on the emergence of tactical behavior. Furthermore, PCA can help coaches to design representative training tasks according to those tactical patterns captured during match competitions and to compare them depending on situational variables.

Tactical expertise assessment in youth football using representative tasks

Specific football drills improve the development of technical/tactical and physical variables in players. Based on this principle, in recent years it has been possible to observe in daily training a growing volume of small-sided and conditioned games. These games are smaller and modified forms of formal games that augment players’ perception of specific tactics. Despite this approach, the assessment of players’ knowledge and tactical execution has not been well documented, due mainly to the difficulty in measuring tactical behavior. For that reason, this study aims to provide a narrative review about the tactical assessment of football training by using representative tasks to measure the tactical expertise of youth football players during small-sided and conditioned games. This study gives an overview of the ecological approach to training and the principles used for representative task design, providing relevant contribution and direction for future research into the assessment of tactical expertise in youth football.

Effects of Practice and Psychological Pressure on Interpersonal Coordination Failures

Although sports players in the same team try to manage their interpersonal coordination for improved performance, failures such as hesitations and collisions are often seen in interpersonal coordination between teammates. However, it is unclear what factors influence the occurrence of such hesitations and collisions. The purpose of this study was to examine the effects of practice and psychological pressure on the occurrence of hesitations and collisions. A total of 80 right-handed university students (aged 19.1 years ± 0.8; 32 males and 48 females) were randomly assigned into pairs and were instructed to perform a serial-tapping task cooperatively. An apparatus had five buttons in a row, which flashed once in each trial in a quasi-random order. When a flashing button was hit, a corresponding light went off and another button flashed. The participants were instructed that the task was to hit a flashing button as quickly and accurately as possible, and either member of the pair could hit the button. They performed 80 practice trials, 10 trials as a control test, and 10 trials as a pressure test. Before the pressure test, pressure was added by informing them about audience and confiscation of the prize if they could not fulfill a criterion. As a result, the occurrence rates of hesitations and collisions and the performance time significantly decreased from the first 40 trials to the next 40 trials of the practice session. Under pressure, state anxiety, the intention to cooperate, and the occurrence rates of hesitations and collisions increased, though heart rate and performance time did not change. These results suggested that interpersonal coordination improved with practice but deteriorated under pressure.

Quantifying the offensive sequences that result in goals in elite futsal matches

The aim of this study was to quantify the type of offensive sequences that result in goals in elite futsal. Thirty competitive games in the Spanish Primera Division de Sala were analysed using computerised notation analysis for patterns of play that resulted in goals. More goals were scored in positional attack (42%) and from set pieces (27%) compared to other activities. The number of defence to offense "transitions" (n = 45) and the start of offensive plays due to the rules of the game (n = 45) were the most common type of sequences that resulted in goals compared to other patterns of play. The central offensive zonal areas were the most common for shots on goal, with 73% of all goals scored from these areas of the pitch compared to defensive and wide zones. The foot was the main part of the body involved in scoring (n = 114). T-pattern analysis of offensive sequences revealed regular patterns of play, which are common in goal scoring opportunities in futsal and are typical movement patterns in this sport. The data demonstrate common offensive sequences and movement patterns related to goals in elite futsal and this could provide important information for the development of physical and technical training drills that replicate important game situations.

Informational constraints on spontaneous visuomotor entrainment

Past research has revealed that an individual's rhythmic limb movements become spontaneously entrained to an environmental rhythm if visual information about the rhythm is available and its frequency is near that of the individual's movements. Research has also demonstrated that if the eyes track an environmental stimulus, the spontaneous entrainment to the rhythm is strengthened. One hypothesis explaining this enhancement of spontaneous entrainment is that the limb movements and eye movements are linked through a neuromuscular coupling or synergy. Another is that eye-tracking facilitates the pick up of important coordinating information. Experiment 1 investigated the first hypothesis by evaluating whether any rhythmic movement of the eyes would facilitate spontaneous entrainment. Experiments 2 and 3 (respectively) explored whether eye-tracking strengthens spontaneous entrainment by allowing the pickup of trajectory direction change information or allowing an increase in the amount of information to be picked-up. Results suggest that the eye-tracking enhancement of spontaneous entrainment is a consequence of increasing the amount of information available to be picked-up.

Footballers' movement behaviour during 2-, 3-, 4- and 5-a-side small-sided games

The aim of this study was to compare footballers' movement behaviour during 2-, 3-, 4- and 5-a-side small-sided games. Ten young professional players (age = 18.0 ± 0.67 years) participated in 3 bouts of each small-sided games for 6 min with 1 min of active rest between bouts. Positional data were collected using GPS system units and used to calculate the following variables: team centroid, distance between each player and own and opponent team centroids and distance between centroids. Approximate entropy was used to identify the time series regularity for each variable. The distance to own team centroid increased with the number of players (effect sizes from moderate to perfect). The results from the distance to the opponent's centroid exhibited a similar trend. The distance between centroids decreased from 2- to the 4-a-side, but then increased in 5-a-side. A higher number of players were associated with lower approximate entropy values, suggesting higher positional organisation in small-sided games with more players. The highest movement regularity found in 4- and 5-a-side identified these formats as more adequate to promote team-related emergent and self-organised behaviours.

The effects of congested fixtures period on tactical and physical performance in elite football

The aim of this study was to examine the physical and tactical performances of a professional football team under congested and non-congested fixture periods. Six home matches of an English professional football team were analysed during competitive season (3 matches distancing three days from the previous fixture and 3 matches distancing six or more days from the previous fixture). Players' physical performances were measured by the total distance covered and distance covered at different speed categories. Tactical performances were measured by the percentage of time of players' movement synchronisation of lateral and longitudinal displacements. This variable was calculated considering all the possible pairs of outfield players, for the overall match and at different speed categories. Results showed no differences in the physical performance, although players' spent more time synchronised during the non-congested fixtures compared to congested fixtures, both for lateral (41.26% to 38.51%, ES: -0.3, P < 0.001) and longitudinal displacements (77.22% to 74.48%, ES: -0.5, P < 0.001). These coordination differences were particularly evident at the lower speed categories and in dyads composed by positions that tend to be further apart during the match, typically central and wing positioned players. Tactical performance seems to be affected by fixtures distribution, with players' spending more time synchronised during the non-congested fixtures. As players' cover the same amount of distance at similar intensities in both fixtures distribution, this reduction of synchronisation may be associated with an increased perception of fatigue and consequent adaptation strategies.

Angular relationships regulate coordination tendencies of performers in attacker-defender dyads in team sports

This study examined the continuous interpersonal interactions of performers in dyadic systems in team sports, as a function of changing information constraints. As a task vehicle, we investigated how attackers attained success in 1v1 sub-phases of basketball by exploring angular relations with immediate opponents and the basket. We hypothesized that angular relations would convey information for the attackers to dribble past defenders. Four basketball players performed as an attacker and defender in 1v1 sub-phases of basketball, in which the co-positioning and orientation of participants relative to the basket was manipulated. After video recording performance behaviors, we digitized participant movement displacement trajectories and categorized trials as successful or unsuccessful (from the attackers' viewpoint). Results revealed that, to successfully dribble past a defender, attackers tended to explore the left hand side of the space by defenders by increasing their angular velocity and decreasing their angular variability, especially in the center of the court. Interpersonal interactions and goal-achievement in attacker-defender dyads appear to have been constrained by the angular relations sustained between participants relative to the scoring target. Results revealed the functionality of exploratory behaviors of participants attempting re-align spatial relations with an opponent in 1v1 sub-phases of team games.

Embodiment of intersubjective time: relational dynamics as attractors in the temporal coordination of interpersonal behaviors and experiences

This paper addresses the issue of “being together,” and more specifically the issue of “being together in time.” We provide with an integrative framework that is inspired by phenomenology, the enactive approach and dynamical systems theories. To do so, we first define embodiment as a living and lived phenomenon that emerges from agent-world coupling. We then show that embodiment is essentially dynamical and therefore we describe experiential, behavioral and brain dynamics. Both lived temporality and the temporality of the living appear to be complex, multiscale phenomena. Next we discuss embodied dynamics in the context of interpersonal interactions, and briefly review the empirical literature on between-persons temporal coordination. Overall, we propose that being together in time emerges from the relational dynamics of embodied interactions and their flexible co-regulation.

Numerical relations and skill level constrain co-adaptive behaviors of agents in sports teams

Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national--NLP and regional-level--RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed emergence of co-adaptive behaviors between interacting neurobiological social system agents in the context of sport performance. Such observations have broader implications for training design involving manipulations of numerical relations between interacting members of social collectives.

Thought self-leadership and effectiveness in self-management teams

This study empirically examines the multilevel nature of thought self-leadership at work. Furthermore, this study tests the relationship between team level thought self-leadership and team effectiveness (i.e. performance and viability) through collective efficacy. A total of 103 self-management teams (453 individuals), enrolled in a five-week management competition participated in the study. The results from multilevel confirmatory factor analysis suggest that thought self-leadership is functionally equivalent across levels of analysis (i.e. individuals and teams). In addition, we found an indirect effect of team level thought self-leadership on team effectiveness criteria, through collective efficacy. These findings extend previous work on thought self-leadership and team effectiveness, and open new roads for research in self-managing work teams. Finally, this study also provides guidelines for organizations in case they wish to foster team performance and viability in their work force.

Coupling tendencies during exploratory behaviours of competing players in rugby union dyads

This study investigated interpersonal coordination tendencies in 1vs.1 dyads in rugby union, here expressed by participants' movement velocity towards or away from the sideline as they competed to score or prevent a try. We examined whether coupling tendencies of members of each dyad shaped key performance outcomes (try or successful tackle). Data on movement displacement trajectories of eight male rugby union players (aged 11-12 years) were analysed during performance in 47 trials. To assess coordination tendencies during exploratory behaviours in the dyads, analyses of performance time series data were undertaken using variable time graphs, running correlations and cross-correlations. Results revealed distinct coupling patterns characterised by shifts between synchronous coordination and asynchronous coordination tendencies and uncoordinated actions. Observed behaviours were interpreted as attempts of competing participants to create and perceive possibilities for action while seeking to achieve specific performance goals. Findings also revealed that a variety of patterned relations between participants resulted in different performance outcomes.

Competing with lower level opponents decreases intra-team movement synchronization and time-motion demands during pre-season soccer matches

This study aimed to quantify the time-motion demands and intra-team movement synchronization during the pre-season matches of a professional soccer team according to the opposition level. Positional data from 20 players were captured during the first half of six pre-season matches of a Portuguese first league team. Time-motion demands were measured by the total distance covered and distance covered at different speed categories. Intra-team coordination was measured by calculating the relative phase of all pairs of outfield players. Afterwards, the percentage of time spent in the −30° to 30° bin (near-in-phase mode of coordination) was calculated for each dyad as a measure of space-time movement synchronization. Movement synchronization data were analyzed for the whole team, according to each dyad average speed and by groups of similar dyadic synchronization tendencies. Then, these data were compared according to the opponent team level (first league; second league; amateurs). Time-motion demands showed no differences in total distance covered per opposition levels, while matches opposing teams of superior level revealed more distance covered at very high intensity. Competing against superior level teams implied more time in synchronized behavior for the overall displacements and displacements at higher intensities. These findings suggest that playing against higher-level opponents (1^st league teams) increased time-motion demands at high intensities in tandem with intra-team movement synchronization tendencies.