The role of perspective in refereeing: Insights from a video-based decision-making experiment.

Decision accuracy is a crucial factor in the evaluation of refereeing performance. In sports research, officials' decision-making is frequently assessed outside real games through video-based decision experiments, where they evaluate recorded game situations from a third-person perspective. This study examines whether the inclusion of the first-person perspective influences decision accuracy and certainty. Twenty-four professional officials from the first and second German basketball leagues participated in the study. The officials assessed 50 game situations from both first-person and third-person perspectives, indicating their decisions and certainty levels. The statistical analysis utilises signal detection theory to evaluate the efficacy of the first-person perspective compared to the third-person perspective in identifying rule violations and no-calls in video recordings. The findings indicate that the first-person perspective does not yield superior accuracy in identifying foul calls. However, scenes from the first-person perspective exhibit a significant 9% increase in correctly identifying no-calls. Furthermore, officials report significantly higher levels of decision certainty and comfort when using the first-person perspective. The study suggests that sports officials may benefit from incorporating additional scenes from the first-person perspective into video-based decision training. Future studies should explore whether this additional perspective improves the training effect and translates into enhanced in-game performance.

Shot deception in basketball: Gaze and anticipation strategy in defence.

Anticipation of teammates and opponents is a critical factor in many sports played in interactive environments. Deceptive actions are used in sports such as basketball to counteract anticipation of an opponent. In this study, we investigated the effects of shot deception on the players' anticipation behaviour in basketball. Thirty one basketball players (15 expert, 16 novice) watched life-sized videos of basketball players performing real shots or shot fakes aimed at the basket. Four different shot outcomes were presented in the video stimuli: a head fake, a ball fake, a high shot fake, and a genuine shot. The videos were temporally occluded at three different time points (-160 ms, -80 ms, 0 ms to ball release) during a shooting motion. The participants had to perform a basketball-related response action to either shots or shot fakes. Response accuracy, response time, and decision confidence were recorded along with gaze behaviour. Anticipation accuracy was reduced at later occlusion points for fake shooting actions. For expert athletes, this effect occurred at later occlusion points compared to novices. The gaze analysis of successful and unsuccessful shot anticipations revealed more gaze fixations towards the hip and legs in successful anticipations, whereas more fixations towards the ball and the head were found in shots unsuccessfully anticipated. It is proposed that hip and leg regions may contain causal information concerning the vertical trajectory of the shooter and identifying this information may be important for perceiving genuine and deceptive shots in basketball.

The Defender's Vision-Gaze Behavior of One-on-One Defenders in Basketball.

In fast-paced team sports, anticipation is one important element in defense strategies. The primary objective of this study was to examine the recommendation for action and use of defensive gaze strategies by defensive players in basketball. Four national-level expert-basketball coaches were interviewed and a field study with mobile eye-tracking devices was conducted on 16 expert and 16 novice players defending in a one-on-one situation. Differences in relative fixation times between experts and novices were elaborated for the predetermined gaze zones-head, ball, torso, and feet-as given by the expert coaches. This was done for three phases of the movement sequence: receiving, dribbling, and shooting. The results of the interviews with expert coaches indicated that the existing coaching doctrine instructs players to look at the torso of an opponent to avoid being vulnerable to fakes. Surprisingly, our findings with the players showed a discrepancy in the evaluated gaze behavior of the experts and novices. For the receiving and dribbling phase, experts mainly fixated their gaze on the head while novices focused on the ball. For the final shooting phase, both the groups mainly fixated their gaze on the ball. Fixating the gaze on the ball or head makes the player potentially vulnerable to deceptive movements, as video-based research has shown. Expert coaches also indicated that peripheral vision is of importance to defenders, contradicting the existing assumption in the literature that focusing on the task-relevant areas is key for anticipation performance.

Shot fakes as an indicator of successful offense in basketball.

Past research has shown that tactical skills can increase the offensive output in basketball. Laboratory studies have confirmed this and indicated that fakes are useful, but their effectiveness is a function of expertise. In recent times, experts in the field have been able to correctly identify fakes with a higher accuracy. In this study, the primary objective was to investigate the offensive technical-tactical play shot fakes as a possible performance indicator in real basketball games. Furthermore, we evaluated how the attacker's initial offensive positioning and location on court influence the effectiveness of such shot fakes. We examined 45 NBA games using post-hoc video analyses. Though, on an average, a tenth of all points were scored after a shot fake, our data showed a significantly higher offensive effectiveness of possessions with a shot fake compared to the games' average for all offensive possessions. Moreover, shot fakes were found to be more effective being initially open, and were more often used when the focus player was being covered by a defender. In addition, 73% of all shot fakes were successful and advantageous for the attacker. This result, in conjunction with previous laboratory studies in which experts showed an above average probability of detection, points to the importance of time pressure for representative study designs. The evidence from this study proves that shot fakes are an important and effective offensive tool to gain an advantage over the opponent and increase offensive scoring, thereby setting the foundation for future research on shot fakes across sports.

Effects of Arm Dominance and Decision Demands on Change of Direction Performance in Handball Players.

This field study investigated the effect of unilateral dominance (handedness of players) on the change of direction speed in a specific cutting manoeuvre with a ball (in the direction of the throwing arm vs. against the direction of the throwing arm) in team handball. In addition, the effect of a cutting manoeuvre in response to an immediate stimulus compared to one planned in advance on the movement speed was analysed. Forty participants (22 male, 18 female, Mage 23 years) performed change of direction actions to the left and the right side (the direction of the throwing arm vs. against the direction of the throwing arm) under planned and reactive (light as visual stimuli) conditions. Change of direction speed was measured post-hoc by video-analyses. The results showed two effects. First, the decision demand in reaction to a visual stimulus reduced the speed in the change of direction compared to the planned action. Second, participants performed their action faster in the direction of the throwing arm than against it. The results replicate the effects of decision demands of previous studies and regardless of the reaction to the stimuli being unspecific, further studies could investigate if specific training can reduce the speed loss due to decision demands. The lateral speed differences of cutting manoeuvres of handball players have been analysed for the first time in this study. This effect could have several causes (e.g., coordination, power, motivation) which should be investigated in future studies in more detail.

The Integration of Wheelchair Users in Team Handball.

Thus far, there are only a few sports activities in which people with and without intellectual disabilities can participate together and on an equal footing. The situation is even more complicated when people who are dependent on a wheelchair want to take part. The sports project Freiwurf Hamburg aims to make team handball playable for everyone. This case study documents how this can be achieved with a modified version of the handball game for runners and wheelchair users. Qualitative and quantitative data are collected and evaluated. The results show that players tend to distinguish between the roles of runner and wheelchair user rather than between disabled and non-disabled.

Adaptive Gaze Behavior and Decision Making of Penalty Corner Strikers in Field Hockey.

In recent years, studies have increasingly dealt with the interaction of gaze behavior and decision making of team sports athletes. However, there is still a variety of important game situations, for example, in the case of penalty corners in field hockey, in which this interaction has not been investigated in detail yet. Penalty corners present a meaningful goal scoring opportunity by providing a relatively free shot. This paper considers two studies. The first study investigated a possible connection between the gaze behavior and the quality of decisions of experienced field hockey players and evaluated the level of success of different gaze strategies. A preliminary study (Study 1) was designed as a survey questionnaire with the aim of preparing for the main study by obtaining subjective assessments of the individual gaze behavior and decision making of professional athletes. In the second and the main study (Study 2), the gaze behavior of experienced field hockey players was recorded using mobile eye-tracking systems to analyze different strategical approaches in associated gaze behavior and decision making. Study 1 showed that players consider reacting to the defenders' behavior during a penalty corner a promising avenue for improving success at penalty corner attempts. It also indicated that such defense-dependent strategies are currently only rarely employed. Study 2 demonstrated how gaze behavior differs between different strategical approaches of the offense. It was shown that the gaze direction on the ball, the stopper, and the goal area is important to allow for a more optimal adaptation to the tactical behavior of defense. It can be concluded that adaptive decision making (i.e., choosing which variation will be carried out just after the "injection" of the ball) seems promising but requires further training to improve the success rate of penalty corner.

Gaze Coordination of Groups in Dynamic Events - A Tool to Facilitate Analyses of Simultaneous Gazes Within a Team.

The performance and the success of a group working as a team on a common goal depends on the individuals' skills and the collective coordination of their abilities. On a perceptual level, individual gaze behavior is reasonably well investigated. However, the coordination of visual skills in a team has been investigated only in laboratory studies and the practical examination and knowledge transfer to field studies or the applicability in real-life situations have so far been neglected. This is mainly due to the fact that a methodological approach along with a suitable evaluation procedure to analyze the gaze coordination within a team in highly dynamic events outside the lab, is still missing. Thus, this study was conducted to develop a tool to investigate the coordinated gaze behavior within a team of three human beings acting with a common goal in a dynamic real-world scenario. This team was a (three-person) basketball referee team adjudicating a game. Using mobile eye-tracking devices and an indigenously designed software tool for the simultaneous analysis of the gaze data of three participants, allowed, for the first time, the simultaneous investigation of the coordinated gaze behavior of three people in a highly dynamic setting. Overall, the study provides a new and innovative method to investigate the coordinated gaze behavior of a three-person team in specific tasks. This method is also applicable to investigate research questions about teams in dynamic real-world scenarios and get a deeper look at interactions and behavior patterns of human beings in group settings (for example, in team sports).

The impact of team preferences on soccer offside judgments in laypersons: a quasi-experimental study.

The present study uses a quasi-experimental design to investigate the impact of team preferences on the accuracy of offside judgments. In Experiments 1 and 2, supporters of two German soccer clubs (i.e., Borussia Dortmund and FC Schalke 04) judged offsides in artificial scenes from a match between the clubs. We expected that supporters of both clubs would less frequently report the offside position of a forward from the preferred team. The results of Experiment 1 partly confirmed the predictions. Both groups reported the offside position of a yellow forward less frequently than that of a blue forward, and this effect was much larger for supporters of Borussia Dortmund than for supporters of Schalke 04. The difference between groups could be attributed to team preferences. The weaker effect of team preference in supporters of Schalke 04 was attributed to an unexpected perceptual effect that increased the accuracy of offside judgments for blue forwards in both groups. Experiments 2 and 3 showed the presumed effect of team preferences and the perceptual effect, respectively, in isolation. In summary, the results of our experiments provide evidence for (a) an effect of team preferences and (b) an effect of shirt-background contrast on offside judgments in soccer.

Response requirements affect offside judgments in football (soccer).

Judging offside in football represents a typical go-nogo task (offside-raising the flag, no offside-no response). Nevertheless, several studies involved two-choice tasks (e.g. offside-press key A, no offside-press key B) to investigate potential sources of errors in offside situations. While go-nogo and choice-response tasks are commonly used in experimental psychology, response preferences may differ between the two tasks. Therefore, we investigated the impact of response requirements on offside judgments in a sample of male participants without experience in professional refereeing. Each participant judged displays of potential offside situations in a go-nogo condition and in a two-choice condition. The results show that response requirements affected the response bias of the participants and suggest that go-nogo requirements increase the preference for the positive response (i.e. the offside response) as compared to the two-choice task. We discuss both methodological and theoretical implications of this finding.

Foul or No Foul? Effects of Permitted Fouls on the Defence Performance in Team Handball.

Attacking phases in team handball are highly dynamic, characterized by fast movements and a high frequency of fast passes with the aim to score a goal. Consequently, the opposing/defending team tries to prevent successful offensive actions by restraining the offensive opportunities and the probabilities of scoring a goal. According to the rules, defensive players are allowed to use body contact (e.g. with bent arms) to get in and keep their optimal defending position. If such a contact is not in line with the rules (e.g. clutching or pushing) and results in a turnover of ball possession, a foul is called and a free-throw awarded. However, there is a lack of research answering the question if a permitted foul (without personal sanction) is an effective way to increase the probability of defending the own goal successfully, because afterwards the attacking team keeps possession of the ball. Thus, we investigated 1052 attacking phases during games at the elite level to verify whether fouls committed by a defender influenced successful attacking (goal vs. no goal). It was found that when the attack was interrupted by a permitted foul, 50.60% of the attacks ended with a goal. Yet, when no foul was committed, only 47.09% of the attacks ended with a goal, however, the analysis revealed that this difference was not significant. Therefore, we concluded that neither a strategy of stopping offensive actions by body contact nor avoiding fouls and focusing only on intercepting the ball were favourable solutions in successful defending in team handball. It seems effective to implement a defence strategy with clearly defined fouling zones and situations, to deal with the tactical possibility of permitted fouls in handball. This idea and further considerations are discussed for sports practice.

Top 10 Research Questions Related to Teaching Games for Understanding.

In this article, we elaborate on 10 current research questions related to the "teaching games for understanding" (TGfU) approach with the objective of both developing the model itself and fostering game understanding, tactical decision making, and game-playing ability in invasion and net/wall games: (1) How can existing scientific approaches from different disciplines be used to enhance game play for beginners and proficient players? (2) How can state-of-the-art technology be integrated to game-play evaluations of beginners and proficient players by employing corresponding assessments? (4) How can complexity thinking be utilized to shape day-to-day physical education (PE) and coaching practices? (5) How can game making/designing be helpfully utilized for emergent learning? (6) How could purposeful game design create constraints that enable tactical understanding and skill development through adaptive learning and distributed cognition? (7) How can teacher/coach development programs benefit from game-centered approaches? (8) How can TGfU-related approaches be implemented in teacher or coach education with the goal of facilitating preservice and in-service teachers/coaches' learning to teach and thereby foster their professional development from novices to experienced practitioners? (9) Can the TGfU approach be considered a helpful model across different cultures? (10) Can physical/psychomotor, cognitive, affective/social, and cultural development be fostered via TGfU approaches? The answers to these questions are critical not only for the advancement of teaching and coaching in PE and sport-based clubs, but also for an in-depth discussion on new scientific avenues and technological tools.

Soccer Offside Judgments in Laypersons with Different Types of Static Displays.

Four experiments investigated offside decisions in laypersons with different types of static displays. Previous research neglected this group although the majority of assistant referees in soccer games at the amateur level are laypersons. The aims of our research were (a) to investigate the spatial resolution in laypersons' perception of offside situations, (b) to search for biases in laypersons' offside judgments, and (c) to develop useful displays for future research. The displays showed the moment when a midfielder passes the ball to a forward moving in the vicinity of a defender. We varied the spatial location of the forward around the defender in eleven steps and participants made their offside decision by pressing a key. Across experiments, displays varied in abstractness (simple shapes, clipart figures, photographs). There were two major findings. Firstly, both accuracy and speed of offside judgments deteriorated when the spatial distance between forward and defender decreased, approaching guessing rate at the smallest distances. Secondly, participants showed a consistent bias in favor of the non-offside response, in contrast to most studies on professional assistant referees. In sum, the results highlight the limited spatial resolution of the visual system and underscore the role of response bias in offside-judgment tasks.