Soccer Environment Research Articles

Perspectives on the role of nutrition in influencing academy soccer player development and performance: A qualitative case study of key stakeholders from an English category one soccer academy

ABSTRACT This study aimed to explore player and stakeholder perceptions of the role of nutrition in influencing the development of male academy soccer players. Semi-structured interviews (28 ± 13 mins in length) were conducted with 31 participants from an English category one academy, including players (Youth Development Phase, YDP: n = 6; Professional Development Phase, PDP: n = 4), parents/guardians (n = 10), coaches (n = 3), sport scientists (n = 3), physiotherapists (n = 3), and catering (n = 2). Via reflexive thematic analysis, data demonstrate an apparent lack of understanding and awareness on the role of nutrition in influencing player development, especially in relation to growth, maturation and reducing injury risk. Players highlighted the influence of their parents on their dietary behaviours, whilst parents also called for education to better support their sons. Notably, players and stakeholders perceived that the daily schedule of an academy soccer player presents as “too busy to eat”, especially in relation to before school, and before and after training. The results demonstrate the necessity for the co-creation of player and stakeholder specific nutrition education programmes as an initial step towards positively impacting the nutrition culture associated with the academy soccer environment.

Contemporary practices of physical trainers in professional soccer: A qualitative study.

Physical trainers (PTs) are integral for managing load, reducing injury and optimizing performance in professional soccer. However, little is known about how this practitioners operate in the applied setting and how some of the nuances experienced influence practice. This study explored the contemporary practices of PTs in professional soccer. Semi-structured interviews were undertaken with eight PTs from different professional teams in European and South American leagues. Interview questions were designed to extract information on the evaluation of physical abilities, monitoring and control of training and injury prevention. Subsequently, the interviews were video-recorded, transcribed, translated and analyzed using a content analysis approach. The results suggest that the evaluation of physical capacities is carried out by PTs at the beginning of the preseason. It also appears that it is attempted that this process of regular testing is applied during the competitive period, with most participants conducting partial physiological and physical evaluations at different stages throughout the competitive season. In relation to the monitoring and control of training, subjective feedback scales are used to estimate the internal load, and the use of GPS devices is common to quantify external loads. Injury prevention programmes were implemented by all participants and were generally in a multi-component format focused on preventing or optimizing physical capabilities. These insights can be used as a scientific reference point to inform applied practice in professional soccer, especially for practitioners that are inexperienced and aspiring to enhance how they operate in the field. Future investigations should explore the practices of PTs in detail and across a wider network in order to gain deeper and comprehensive insights into the applied soccer environment.

축구선수의 은퇴인식 및 은퇴준비의 심층 분석

Objectives In this study, we will analyze in-depth the retirement awareness and retirement preparation of soccer players to explore what they perceive and recognize retirement awareness and retirement preparation as and what are the constituent factors.
 Methods To this end, this study adopted an open questionnaire and a focus group interview method. The open questionnaire surveyed 259 university, professional, and semi-professional soccer players, and the data collected through this were analyzed inductive content. Since then, in order to secure integrity, validity, and identity, a focus group interview (FGI) was conducted with 7 soccer players to understand in-depth the retirement awareness and retirement preparation of soccer players.
 Results As a result of the inductive content analysis of the open-ended questionnaire on the retirement awareness of soccer players, 647 detailed original data were derived, and 9 subcategories and 5 upper categories were derived. The five upper categories were derived as “Psychological conflict”, “Fear of the future”, “Challenge”, “Bittersweet”, and “Others”. From the results of the FGI analysis, actual and in-depth interview data on the retirement awareness of soccer players were derived. As a result of the open-ended question analysis on soccer players' retirement preparation, 607 detailed original data, 10 subcategories, and 7 upper categories were derived. The 7 derived categories were “Leader Preparation”, “Economic Preparation”, “Intellectual Competency Preparation”, “Interpersonal Relationship”, “Career Search”, “Focus on the present”, and “Others”.
 Conclusions The results of this study will be able to provide empirical data on soccer players' positive perception of retirement and efficient preparation, and ultimately lead soccer players' future happy lives and suggest a direction for soccer player welfare. In order to build a better retirement environment for players, it seems that members in the soccer environment must take the lead in creating it.

How to Balance the Foreign Players and Local Players to Develop Chinese Soccer

Foreign athletes are a common phenomenon in all kinds of leagues around the world. It not only contributes effectively to the improvement in performance but also leads to an active football market. But in the Chinese soccer league, a low-level soccer league, how to utilize these international super players to improve the skills and tactics of local players is significant to change the current situation in the Chinese soccer environment. This research could be conducted through observation, SWOT analysis, and literature review methods to analyze how international players drive the development of local players and improve the development of Chinese soccer. The result shows that to improve the youth football training system, the CFA should make thorough policies or rules, expand the number of teams, improve the management system of football agents and clubs should establish a sound system for the management and introduction of foreign players.

Free-play street soccer environments: examining youth sport injury risk through a biopsychosocial lens

ABSTRACT This review of literature articulates how the ‘free-play’ street soccer environment creates the context for athletes to thrive in sport, while simultaneously minimizing the injury risks associated with such activity. Williams’ and Andersen's well-known model of stress and athletic injury outlines how athletes’ cognitive and physiological responses to potentially stressful athletic situations can influence sport injuries. This ‘stress response’ is influenced by the personality, history with stressors, and coping resources that athletes bring to the environment. Wiese-Bjornstal furthered theory in this domain by developing the biopsychosocial sport injury risk profile. Her framework identifies potential antecedents to injury that emerge across four categories, each of which holds various levels of risk exposure, risk behavior, and vulnerability to injury: biological, physical, psychological, and sociological. These models provided the framework for this narrative. Specifically, given its psychosocial nature, the free-play street soccer environment may act as a protective sport activity design insofar as it mitigates against known injury risk antecedents. Hence, the inherent risk mitigation of free-play, taken together with the potential it has to create psychological, physiological, and technical development among young people, support greater emphasis on street soccer as a powerful construct for youth development in the game of soccer.

Parameter Adjustment of EROS Humanoid Robot Soccer using a Motion Visualization

Humanoid robot is a robot whose overall appearance is formed based on the human body and can interact with equipment and the environment created by humans. The robot's balance becomes fundamental in carrying out various tasks in designing humanoid robots. To deal with this, the adjustment of the humanoid robot movement is crucial in this work, research related to the virtual visualization of robots. Virtual robot visualization can be done by creating a simulator that contains dynamic parameters, including the physics of the robot. With the simulation containing dynamic parameters, the humanoid robot movement can be tried many times until the robot movement is robust. Applying the URDF (Unified Robot Description Format) model to the Gazebo simulator, which is supported by the ROS (Robot Operating System) framework, can make a simulator with dynamic parameters mimicking a real environment. In order to make a robust robot motion, feedback is needed in position and torque to find out the difference between simulation and reality. On the other hand, simulations can be done without cost or risk and, most importantly, mimic the actual robot soccer environment.

Programmatic Modeling and Generation of Real-Time Strategic Soccer Environments for Reinforcement Learning

The capability of a reinforcement learning (RL) agent heavily depends on the diversity of the learning scenarios generated by the environment. Generation of diverse realistic scenarios is challenging for real-time strategy (RTS) environments. The RTS environments are characterized by intelligent entities/non-RL agents cooperating and competing with the RL agents with large state and action spaces over a long period of time, resulting in an infinite space of feasible, but not necessarily realistic, scenarios involving complex interaction among different RL and non-RL agents. Yet, most of the existing simulators rely on randomly generating the environments based on predefined settings/layouts and offer limited flexibility and control over the environment dynamics for researchers to generate diverse, realistic scenarios as per their demand. To address this issue, for the first time, we formally introduce the benefits of adopting an existing formal scenario specification language, SCENIC, to assist researchers to model and generate diverse scenarios in an RTS environment in a flexible, systematic, and programmatic manner. To showcase the benefits, we interfaced SCENIC to an existing RTS environment Google Research Football (GRF) simulator and introduced a benchmark consisting of 32 realistic scenarios, encoded in SCENIC, to train RL agents and testing their generalization capabilities. We also show how researchers/RL practitioners can incorporate their domain knowledge to expedite the training process by intuitively modeling stochastic programmatic policies with SCENIC.

An Examination of the Experiences of Practitioners Delivering Sport Psychology Services within English Premier League Soccer Academies.

Sport psychology has become increasingly recognized and accepted within professional sports, including soccer. To date, there is a lack of research that examines the provision of sport psychology within elite soccer, particularly from the experience of applied practitioners working within the field. The current study adopted a qualitative, inductive approach, to examine the experiences of practitioners responsible for sport psychology delivery within elite soccer academies in England. Seven participants (four females; three males), working within academies in the English Premier League, took part in semi-structured interviews about their experience of delivering sport psychology services within elite soccer academies. Results demonstrated that the provision of sport psychology is continually evolving, yet there are a number of factors that appear to inhibit the full integration of the discipline into academy soccer. Six key themes were identified: The breadth of sport psychology provision; what is sport psychology; the stigma surrounding sport psychology services; psychological literacy; the elite youth soccer environment; and the delivery of sport psychology under the Elite Player Performance Plan. Participants identified a lack of psychological literacy among coaches and academy staff, as well as a low level of guidance regarding the provision of psychology within the England Football Association’s guiding document—the Elite Player Performance Plan—leading to considerable variation in the nature of the sport psychology provision. Future research would do well to also sample from a range of staff working within English soccer academies, in order to assess their perception of the level of provision and understanding of psychology.

Multiagent Reinforcement Learning for Strategic Decision Making and Control in Robotic Soccer Through Self-Play

Reinforcement Learning (RL) has shown promising performance in environments for both robotic control and strategic decision making. However, they are usually treated as separate problems with different objectives. In this work, we propose the use of Reinforcement Learning to solve both control and strategic problems as one, in a multi-agent robotic soccer environment. We use the IEEE Very Small Size Soccer (VSSS) challenge from the Latin American Robotics Competition (LARC) as a study case. In the VSSS, two autonomous teams of wheeled robots compete by pushing the ball around to score goals. To unify both control and strategy problems, our approach gives full control of the actuators’ speed to the RL algorithm whilst keeping the broader objective of winning the game. Our method achieves win rates as high as 93% against hand-coded heuristic strategies. In this work we contribute by developing an RL agent that can learn from self-play and generalize against new opponents. Our methodology uses multi-agent Reinforcement Learning with self-play in order to build up the knowledge for complex tasks. We also developed a simulated environment for the robotic soccer game.

When it is no longer a bit of banter: Coaches’ perspectives of bullying in professional soccer

ABSTRACT Studies exploring bullying in sport psychology remain relatively limited despite various media reports of the abusive practice of some professional soccer coaches. This research explores coaches’ views of bullying in professional soccer academies and how it is framed in relation to banter. Five professional soccer coaches were interviewed using a semi-structured interview guide. The methodology and analysis were guided by interpretative phenomenological analysis. Coaches highlighted key components which identify bullying in professional soccer environments, such as intent to harm; frequency of behaviour; and an imbalance of power. Coaches also highlighted different individual and contextual factors which separated bullying from banter. These included individual differences; unintentional behaviour; immaturity; and the masculinity of the soccer culture. These findings provide an important extension to the bullying literature in sport by highlighting coaches’ own perspectives on this concept within the professional soccer context. The findings also illustrate the subtle nuances through which coaches separate bullying from banter. As such, important applied implications are discussed for the development of coach education programmes to raise greater awareness around these concepts as well as the potential consequences of bullying and banter on player welfare in professional soccer.

Two-stage training algorithm for AI robot soccer.

In multi-agent reinforcement learning, the cooperative learning behavior of agents is very important. In the field of heterogeneous multi-agent reinforcement learning, cooperative behavior among different types of agents in a group is pursued. Learning a joint-action set during centralized training is an attractive way to obtain such cooperative behavior; however, this method brings limited learning performance with heterogeneous agents. To improve the learning performance of heterogeneous agents during centralized training, two-stage heterogeneous centralized training which allows the training of multiple roles of heterogeneous agents is proposed. During training, two training processes are conducted in a series. One of the two stages is to attempt training each agent according to its role, aiming at the maximization of individual role rewards. The other is for training the agents as a whole to make them learn cooperative behaviors while attempting to maximize shared collective rewards, e.g., team rewards. Because these two training processes are conducted in a series in every time step, agents can learn how to maximize role rewards and team rewards simultaneously. The proposed method is applied to 5 versus 5 AI robot soccer for validation. The experiments are performed in a robot soccer environment using Webots robot simulation software. Simulation results show that the proposed method can train the robots of the robot soccer team effectively, achieving higher role rewards and higher team rewards as compared to other three approaches that can be used to solve problems of training cooperative multi-agent. Quantitatively, a team trained by the proposed method improves the score concede rate by 5% to 30% when compared to teams trained with the other approaches in matches against evaluation teams.

Perceived inclusion in youth soccer teams: The role of societal status and perceived motivational goal climate

ObjectivesOur aim was to investigate the link between youth soccer players' perceptions of the coach-initiated motivational goal climate within their team and their perceptions of inclusion as a function of societal status. Societal status refers to one's national background which numerically forms the majority or a minority in a particular society. Design and methodsSurvey data was collected among 245 male youth soccer players (M = 12.9 years, SD = 1.60), who all played in culturally diverse teams in the Netherlands. The societal status of 94 players (38.4%) was majority, and 151 players (61.6%) were classified as minority. To test our main hypothesis, perceived inclusion as the dependent variable was hierarchically regressed on coach-initiated mastery goal climate perceptions, performance goal climate perceptions, societal status, and their interactions. ResultsOverall, mastery goal perceptions and performance goal perceptions of intra-team competition were positively and negatively related, respectively, to perceived team inclusion. As hypothesized, only among players with a societal minority status, perceptions of inclusion were higher when mastery goal climate perceptions were higher and performance goal climate perceptions were lower. Discussion and conclusionOur findings suggest that a coach-initiated mastery-oriented team climate may enhance an inclusive soccer environment in culturally and nationally diverse teams. For societal minority players, intra-team competition should be de-emphasized by the coach in order to strengthen the experience of inclusion.

Effects of Strength vs. Plyometric Training on Change of Direction Performance in Experienced Soccer Players.

The purpose of this study was to compare how 6 weeks of strength- vs. plyometric training, which were matched upon direction of motion and workload, influences change of direction (COD) performance. Twenty-one experienced male soccer players (age: 22.2 ± 2.7) were pair-matched into a strength- (n = 10) and a plyometric (n = 11) training group. CODs of 45°, 90°, 135° and 180° performed from either a 4 m or 20 m approach distance were compared before and after intervention. Results showed no significant difference between groups. Significant effects were only found within the plyometric training group (−3.2% to −4.6%) in 90°, 135° and 180° CODs from 4 m and a 180° COD from a 20 m approach distance. Individual changes in COD performances showed that with the 4 m approach at least 55% and 81% of the strength and plyometric training group, respectively, improved COD performance, while with the 20 m approach at least 66% of both groups improved performance. This study showed that the plyometric training program can improve most CODs, with angles over 90°, although this is dependent on the distance approaching the COD. Considering the limited time of implementing physical conditioning, in addition to regular soccer practice in most soccer environments, the current plyometric training program can be advantageous in improving CODs at maximal intensity.

A Pre-Match Video Self-Modeling Intervention in Elite Youth Football

In this study, a self-modelling video intervention was delivered to four elite youth soccer players over 13 weeks of the competitive soccer season. A multiple-baseline, repeated measures single-subject design was used to explore the impact of the intervention on subcomponents of soccer performance and psychological variables, including self-efficacy and positive/negative affect. Statistical analysis indicated that there were significant changes between pre- and post-intervention scores for two players (1 & 3) on three subcomponents of performance (turns, headers and tackles). The findings of this study highlight the potential benefits of designing individualised pre-match video interventions with elite youth athletes.Lay Summary: Video self-modelling (VSM) is a behavioural intervention in which an athlete views a video of themselves engaged in adaptive behaviour, in order to learn to reproduce it effectively under pressure. In this study, the impact of a self-modelling video intervention is examined within a youth football soccer environment.

Artificial neural networks and player recruitment in professional soccer.

The aim was to objectively identify key performance indicators in professional soccer that influence outfield players’ league status using an artificial neural network. Mean technical performance data were collected from 966 outfield players’ (mean SD; age: 25 ± 4 yr, 1.81 ±) 90-minute performances in the English Football League. ProZone’s MatchViewer system and online databases were used to collect data on 347 indicators assessing the total number, accuracy and consistency of passes, tackles, possessions regained, clearances and shots. Players were assigned to one of three categories based on where they went on to complete most of their match time in the following season: group 0 (n = 209 players) went on to play in a lower soccer league, group 1 (n = 637 players) remained in the Football League Championship, and group 2 (n = 120 players) consisted of players who moved up to the English Premier League. The models created correctly predicted between 61.5% and 78.8% of the players’ league status. The model with the highest average test performance was for group 0 v 2 (U21 international caps, international caps, median tackles, percentage of first time passes unsuccessful upper quartile, maximum dribbles and possessions gained minimum) which correctly predicted 78.8% of the players’ league status with a test error of 8.3%. To date, there has not been a published example of an objective method of predicting career trajectory in soccer. This is a significant development as it highlights the potential for machine learning to be used in the scouting and recruitment process in a professional soccer environment.

A reversal theory perspective on the motivational states of soccer players in Canada, Germany, and Japan

This descriptive, exploratory study used a reversal theory framework to examine the in-event motivational states of 179 intercollegiate soccer players in Canada, Germany, and Japan. Information was also gathered on players’ thoughts about the university soccer environment. The results suggest that all of the participants were oriented toward the mastery (strength, control) and conformity motivational states while playing. In addition, Japanese players reported the strongest endorsement of the telic (serious) state, and they were more sympathetic and alloic (concerned with others’ outcomes) than the Canadian and German cohorts. With respect to the salience of these motivational states, Canadian players were most aware of the mastery orientation. In Japan it was the telic state that was most dominant, and in Germany it was spread out between the alloic, autic (concern about own outcomes), and mastery states. Other findings, obtained through content analysis, revealed that university soccer in Canada and Japan fosters both a social and performance-focused atmosphere, while in Germany it is perceived as more social and recreational than in the other two countries. These results provide a preliminary foundation for follow-up cross-cultural work. Future research should also examine the motivational states of more elite players (including those in Brazil) and the correlation of these states with winning and losing over time.

FIFA 11+ Warm-up

In an effort to reduce soccer injury rates, the Fédération Internationale de Football Association (FIFA) developed the 11+ warm-up. Widespread uptake of this program remains a challenge despite its effectiveness, but may be increased if positive impacts on physical performance as well as injury risk factors such as neuromuscular control are shown. Effects of the program on physical performance measures and movement control have not been investigated in young female soccer athletes. PURPOSE: To determine the effect of the FIFA 11+ program, compared to a standard warm-up, on movement control, agility, vertical jump (VJ), and core stability in young female athletes after a 5 month indoor soccer season. METHODS: Forty-seven girls from the U10 and U11 divisions of a developmental soccer club were randomized by team to the intervention group (IG) or the control group (CG). IG teams were taught the 11+ warm-up, consisting of 15 exercises broken into 3 sections: 1) slower running drills, 2) strength and plyometric exercises, and 3) faster sprints. The CG continued with their previously planned warm-up. Teams practiced and played 2-3x/week. Blinded assessors conducted pre- and post-season testing of movement control (Landing Error Scoring System), and physical performance (T-test, VJ, and static plank). Two-way Repeated Measures ANOVA analyses were used to compare movement control and physical performance of the groups over time. RESULTS: The IG demonstrated a significantly greater increase in static plank hold time compared to the CG (26.1 ± 38.5 vs. 2.1 ± 37.1 seconds, p=.047). All athletes, regardless of group, improved their LESS score (pre- 6.8 ± 1.6; post-season 6.2 ± 1.4, p=.005) and agility T-test time (pre- 14.2 ± 1.2; post-season 13.8 ± 1.0 seconds, p=.001). No differences were found for the VJ. CONCLUSIONS: The 11+ program, performed over a 5 month indoor soccer season by 9-11 year old soccer players, resulted in improved core stability compared to a regular warm-up, but this did not translate into a significantly greater change in LESS score in the IG. The 11+ program may not be more effective than other dynamic warm-ups at improving neuromuscular control and agility. However, time and space limitations inherent in the indoor soccer environment may have negatively impacted the program’s ability to reach its full potential.

Young Female Soccer Players’ Perceptions of Their Modified Sport Environment

Competitive engineering is a process whereby sport organizations modify the rules, facilities, and equipment involved in sport to facilitate desirable athlete outcomes and experiences. Competitive engineering is being increasingly adopted by youth sport organizations with empirical evidence positively supporting its influence on skill development and performance. The purpose of this study was to explore young female athletes’ experiences in their modified soccer environment. Seventeen recreational and competitive soccer players, aged 8–11, participated in semistructured photo elicitation interviews that featured several visual qualitative methods (i.e., athlete-directed photography, drawing exercises, and pile-sorting) to facilitate insight on their sport environments. Results revealed that the athletes’ competitively engineered soccer experience was perceived as being a distinct environment that emphasized personal development, positive relationships, and the underlying enjoyment of sport. These findings shed light of how youth sport structure modifications influence the athletes’ experiences, providing practical implications to further promote positive youth sport experiences.

An Advising Framework for Multiagent Reinforcement Learning Systems

Reinforcement Learning has long been employed to solve sequential decision-making problems with minimal input data. However, the classical approach requires a long time to learn a suitable policy, especially in Multiagent Systems. The teacher-student framework proposes to mitigate this problem by integrating an advising procedure in the learning process, in which an experienced agent (human or not) can advise a student to guide her exploration. However, the teacher is assumed to be an expert in the learning task. We here propose an advising framework where multiple agents advise each other while learning in a shared environment, and the advisor is not expected to necessarily act optimally. Our experiments in a simulated Robot Soccer environment show that the learning process is improved by incorporating this kind of advice.

Arquitectura Basada en Roles Aplicada en Equipos de Fútbol de Robots con Control Centralizado

Robot soccer offers an adequate domain in order to design and validate architectures for robot-coordination. One classification refers to centralized architectures, which correspond to robot soccer environments with global perception and centralized control of the robots, using only one decision-making system. In this paper it is presented a centralized robot soccer architecture based on roles, where one role is assigned to each player in order to select a specific behaviour depending on game conditions. Roles are assigned using an assignment function, which is activated when the ball changes of the quadrant in the playing field. This strategy has been compared by simulation in games against an opposition team with constant roles, and other team with a hierarchical strategy which assigns roles depending on a tactic previously selected. The results showed a better performance in the team with the role-based strategy outperformed the rest of the methods. As well as uniformity within the players’ behaviors during the role and behavior transitions.