Lateral preference in complex combat situations: Prevalence and relationship with general measures of hand and foot preference.

Laterality is considered relevant to performance in combat sports with particular emphasis being placed on fighters' handedness and combat stance. Such approach, however, may fall too short to understand the role of laterality in sports where fighters are allowed to use their hands and feet standing and on the ground. Here, we referred to grappling sports (i) to estimate lateral preferences in selected combat situations and (ii) to test for an association between those preferences and common measures of hand and foot preference. Based on the responses of 135 experienced grapplers who participated in an online questionnaire lateral preference, at the group-level, was revealed in 12 out of 18 combat situations. At an item-level, common measures of lateral preference and grappling-specific lateral preference were related in three out of 36 conditions (footedness only, not handedness). Across items, scores in a grappling-specific laterality index were positively related with foot but not with hand preference scores. Implications for the assessment of lateral preference in combat sports and the use of item-specific terminology in this context are discussed. On a broader scale, we also elaborate on potential consequences of our findings with regard to evolutionary explanations of the maintenance of left-handedness in humans.

Physical Load and Referees' Decision-Making in Sports Games: A Scoping Review.

Referees in sports games have a high level of responsibility as they have to make correct and appropriate decisions at any point during a match. Regarding referees' decision-making (RDM) as a perceptual-cognitive process, evidence suggests that physical load might reduce cognitive performance and thus might reduce RDM performance as well. In consideration of increasing game dynamics, referees have to cope with high physical load, but they have to make correct and appropriate decisions further on. Here, we review the current state of research on the relationship between physical load and RDM. A scoping review was performed, in accordance with the PRISMA guidelines, using the following databases: Scopus, PubMed, Web of Science (all databases), SURF and SPONET (both with an English and German search). Only primary studies written in English or German that investigated the relationship between physical load and RDM in sports games were included. Eleven studies included in the review investigated six physical parameters and RDM: match period, velocity, blood lactate, running time, heart rate, distance covered. Most findings of the studies showed no relationship between physical load and RDM (n = 18). Thirteen findings suggest a negative relationship and three findings indicate a positive relationship between physical load and RDM. Results of the scoping review show contradictory evidence across and within investigated different physical parameters. As RDM consists of multi-factorial components, it is recommended to conduct systematic research programs - field as well as experimental studies - to resolve the missing control of potential confounding variables and to consider the difference of internal and external load.

Body-specific influences on performance evaluation in realistic dynamic scenes.

According to the body-specificity hypothesis, left-handers (right-handers) are more likely to associate positive attributes with the left (right) side. We tested whether such body-specific influences also apply to evaluative judgments in realistic dynamic scenes. In two experiments (order counterbalanced), N = 231 participants watched videos from dual mogul competition where two skiers turn downhill through moguls side by side simultaneously and then comparatively rated the skiers' technical performances. Experiments differed in the required response mode only. In Exp. 1, participants made forced-choice decisions by selecting either the left or right skier as the better performer; in Exp. 2 graded judgments were made on a 10-point scale ranging from -5 (skier on the left side) to + 5 (skier on the right side). Body-specific associations were found in Exp. 1 (OR = 3.16), but not in Exp. 2 (OR = 1.50). A control experiment (Exp. 3; same participants) revealed that our sample (OR = 2.31) behaved similar to previously reported samples in a well-established cartoon character task, thereby confirming body-specific associations in our sample on a task with abstract static stimuli. Collectively, body-specific associations seem to apply to realistic dynamic scenes, particularly when frugal forced-choice decisions are required.

Goofy vs. Regular: Laterality effects in surfing.

The aim of the present study was to test if lateral preferences of surfers are associated with behaviour and performance depending on the direction of a breaking wave. We hypothesized that wave direction and surf stance interact in creating favourable or debilitative performance demands as surfers are either facing the wave (frontside) or the wave is breaking in the back of the surfers (backside). Study 1 was an online survey collecting self-report data of recreational surfers (n = 394). In Study 2, we analysed all wave scores (n = 2,552) and laterality of professional surfers during the season of 2014. Study 1 demonstrated that recreational surfers preferred surfing frontside and described themselves as more skilful when surfing frontside as this is facilitative for picking up visual information. Study 2 did not provide clear evidence that professional surfers on average scored higher during contests when surfing frontside, but when professional surfers had a choice of surfing frontside vs. backside, they were more likely to surf frontside. We discuss the diverging findings between Study 1 and Study 2 from the "circumvention-of-limits" argumentation within the expertise literature as professional surfers most likely have acquired skills allowing them to compensate for debilitative individual and environmental circumstances.

Left-handedness and time pressure in elite interactive ball games.

According to the fighting hypothesis, frequency-dependent selection gives relatively rarer left-handers a competitive edge in duel-like contests and is suggested as one mechanism that ensured the stable maintenance of handedness polymorphism in humans. Overrepresentation of left-handers exclusively in interactive sports seems to support the hypothesis. Here, by referring to data on interactive ball sports, I propose that a left-hander's advantage is linked to the sports' underlying time pressure. The prevalence of left-handers listed in elite rankings increased from low (8.7%) to high (30.39%) time pressure sports and a distinct left-hander overrepresentation was only found in the latter (i.e. baseball, cricket and table tennis). This indicates that relative rarity and the interactive nature of a contest are not sufficient per se to evoke a left-hander advantage. Refining the fighting hypothesis is suggested to facilitate prediction and experimental verification of when and why negative frequency-dependent selection may benefit left-handedness.

Pushing through evolution? Incidence and fight records of left-oriented fighters in professional boxing history.

The fighting hypothesis proposes that left-oriented athletes enjoy a negative frequency-dependent advantage in combat sports such as boxing. Supporting evidence, however, is restricted to cross-sectional frequency data from small samples. Here, we examined the incidence and fight records of 2,403 left- and right-oriented fighters who were listed in the annual ratings of professional boxing from 1924 to 2012. Unexpectedly, left-oriented boxers were overrepresented in no more than 7 of the 89 years considered, their percentages varied up to 30% and increased over the entire period, and frequencies varied substantially between weight divisions. In support of the fighting hypothesis, lose-win ratios indicated larger fighting strength in left- compared to right-oriented boxers, which, however, was not reflected in different proportions of wins and losses by knockout. Our findings are partly consistent with an assumed left-oriented fighters' advantage in combat sports. Such advantage could be explained by negative frequency-dependent selection mechanisms; however, our study also revealed potential limits of the fighting hypothesis such that alternative explanations cannot be fully excluded. We propose that interference by factors not related to performance could also limit the suitability of data from elite sporting competition for testing evolutionary models of human handedness.

On-court position influences skilled tennis players' anticipation of shot outcome.

When anticipating future events like an opponent's stroke direction in tennis, players are assumed to rely on both kinematic and contextual cues such as an opponent's on-court position. However, knowledge of position dependency in shot-direction probabilities and experimental evidence of the effect of on-court position on action-outcome anticipation is missing. Here we show that shot-direction probabilities vary as a function of a hitting player's on-court position in professional tennis. Moreover, unlike novices, skilled players in particular relied on information about an opponent's position when anticipating forehand baseline shot direction in a video-based experiment. The position dependency in skilled players' prediction behavior was most evident when little information on an opponent's stroke kinematics was available. Findings suggest that skilled players consider the reliability of different information sources by weighting the available contextual and kinematic cues differently in the course of an opponent's unfolding action.

Perception-action coupling in anticipation research: a classification and its application to racket sports.

Anticipation is key to performance in many sports. By definition, anticipation as a perceptual-cognitive process is meant to inform action and help athletes reduce potential motor costs under spatiotemporal pressure. Anticipation research has repeatedly been criticized for neglecting action and raised the need for predominant testing under conditions of perception-action coupling (PAC). To the best of our knowledge, however, there is a lack of explicit criteria to characterize and define PAC conditions. This can lead to blurred terminology and may complicate interpretation and comparability of PAC conditions and results across studies. Here, we make a first proposal for a 7-level classification of PAC conditions with the defining dimensions of stimulus presentation and response mode. We hope this classification may constitute a helpful orientation for study planning and reporting in research on anticipation. Further, we illustrate the potential utilization of the PAC classification as a template for experimental protocol analysis in a review on anticipation in racket sports. Analysis of N = 115 studies reported in N = 91 articles confirms an underrepresentation of representative PAC conditions and reveals little change in PAC approaches over more than 40 years of research in that domain. We discuss potential reasons for these findings, the benefits of adopting the proposed PAC classification and reiterate the call for more action in anticipation research.

Expert goalkeepers' and coaches' views on anticipation and cue utilisation facing backcourt throws in handball goalkeeping.

Introduction: Handball goalkeepers have to act under severe spatio-temporal pressure in both standardised (e.g., 7 m penalty) and non-standardised situations (e.g., backcourt throws) which require them to predict action outcome before ball flight is visible. So far, research on goalkeepers' cue utilisation for anticipation of an opponent's action has mainly focused on 7 m throw situations whereas little attention has been paid to the latter, more complex and far more frequently occurring backcourt throw situations. Methods: To address this gap, we conducted semi-structured interviews with N = 6 expert handball goalkeepers and goalkeeper coaches [all of whom were (former) expert handball goalkeepers] on anticipation and cue utilisation when facing backcourt throws. The interviews were subsequently transcribed, coded and results were inductively as well as deductively categorised by means of a thematic analysis. Results: Results reveal a variety of kinematic and contextual cues relevant for action anticipation that become available before the game and before or during the throw. Participants reported to use information from the offence (e.g., thrower's jump; opposing team's task distribution) and the defence (e.g., defensive players' strategies, block position) for anticipation in backcourt throw situations. Additionally, we identified several factors that influence cue availability and utilisation. Discussion: Our findings provide a thorough basis to (a) guide future research that yields questions on kinematic and contextual cue integration and in-situ cue usage as well as (b) inform the development of training programs to foster goalkeepers' anticipatory skill.

Human handedness in interactive situations: Negative perceptual frequency effects can be reversed!

Left-handed performers seem to enjoy an advantage in interactive sports. Researchers suggest this is predominantly due to the relative scarcity of left-handers compared with right-handers. Such negative frequency-dependent advantages are likely to appear in inefficient game-play behaviour against left-handed opponents such as reduced ability to correctly anticipate left-handers' action intentions. We used a pre-post retention design to test whether such negative frequency-dependent perceptual effects can be reversed via effective training. In a video-based test, 30 handball novices anticipated the shot outcome of temporally occluded handball penalties thrown by right- and left-handed players. Between the pre- and post-tests, participants underwent a perceptual training programme to improve prediction accuracy, followed by an unfilled retention test one week later. Participants were divided into two hand-specific training groups (i.e. only right- or left-handed shots were presented during training) and a mixed group (i.e. both right- and left-handed shots were presented). Our results support the negative frequency-dependent advantage hypothesis, as hand-specific perceptual training led to side-specific improvement of anticipation skills. Similarly, findings provide experimental evidence to support the contention that negatively frequency-dependent selection mechanisms contributed to the maintenance of the handedness polymorphism.

Raw Data Visualization for Common Factorial Designs Using SPSS: A Syntax Collection and Tutorial.

Transparency in data visualization is an essential ingredient for scientific communication. The traditional approach of visualizing continuous quantitative data solely in the form of summary statistics (i.e., measures of central tendency and dispersion) has repeatedly been criticized for not revealing the underlying raw data distribution. Remarkably, however, systematic and easy-to-use solutions for raw data visualization using the most commonly reported statistical software package for data analysis, IBM SPSS Statistics, are missing. Here, a comprehensive collection of more than 100 SPSS syntax files and an SPSS dataset template is presented and made freely available that allow the creation of transparent graphs for one-sample designs, for one- and two-factorial between-subject designs, for selected one- and two-factorial within-subject designs as well as for selected two-factorial mixed designs and, with some creativity, even beyond (e.g., three-factorial mixed-designs). Depending on graph type (e.g., pure dot plot, box plot, and line plot), raw data can be displayed along with standard measures of central tendency (arithmetic mean and median) and dispersion (95% CI and SD). The free-to-use syntax can also be modified to match with individual needs. A variety of example applications of syntax are illustrated in a tutorial-like fashion along with fictitious datasets accompanying this contribution. The syntax collection is hoped to provide researchers, students, teachers, and others working with SPSS a valuable tool to move towards more transparency in data visualization.

Varying Degrees of Perception-Action Coupling and Anticipation in Handball Goalkeeping.

Anticipation in sports is commonly investigated using perception-action uncoupled methods, thus raising questions regarding transferability of findings to the field. The aim of this study was to investigate the influence of different degrees of perception-action coupling on anticipation in handball goalkeeping. Advanced, intermediate and novice handball goalkeepers watched videos of throws on the goal and were asked to anticipate throw direction via key press (perception-action artificial condition) and via natural movement response (perception-action simulated condition). Results reveal overall superior performance in the artificial compared to the simulated condition. Skill-based differences, however, were descriptively more pronounced in the simulated condition compared to the artificial condition. The findings further highlight the importance of more representative research methods to unravel perceptual-cognitive skill in sports.

Handedness and Relative Age in International Elite Interactive Individual Sports Revisited.

Relative age effects (RAE) describe the unintended side effect of annual age grouping such that athletes born close to a specific cutoff date are more likely to be associated with attaining higher performance status than athletes born later. One factor suggested to override the RAE is handedness. Given the left-handers' rarity and their proposed performance advantage in interactive sports, left-handedness may be associated with a lower likelihood of suffering from selection inequalities like RAE in those sports compared with right-handedness. Here, in a two-study approach, we tested that hypothesis by examining male and female athletes from various interactive individual sports sampled over a 10-year period from 2007 to 2016. Study 1 investigated distributions of birth and handedness of senior athletes listed in the top 200 of year-end world rankings in table tennis, tennis, squash, and fencing (épée, foil, and saber). Study 2 followed a similar design but focused on junior athletes in the fencing disciplines and tennis. Unlike the above prediction, in both studies, birth distribution was not found to be reliably associated with handedness in any of the sports or disciplines considered. Left-handers were consistently overrepresented in épée, foil, and table tennis, occasionally in saber and tennis, and not at all in squash. Birth frequencies decreased from quartile Q1 (January to March) to Q4 in almost any sporting domain at the junior level, whereas such trend was rarely found at the senior level. In conclusion, while providing novel insight on the role handedness may play at the junior level, our findings do not support the hypothesis that left-handedness helps override birth-related inequalities in high sporting achievement in elite interactive individual sports.

Automated processes in tennis: do left-handed players benefit from the tactical preferences of their opponents?

Previous research on laterality in sport suggests an over-representation of left-handers in interactive sports such as tennis and cricket. These findings potentially reflect left-handers' advantage over their right-handed competitors in those sports. Although considered crucial for successful performance, the tactical component of their superiority has yet to be analysed. Two studies were conducted to test for a side bias in tennis players' tactical preferences. In the first study, 108 right- and left-handed players of varying skill watched rallies on a computer screen and had to indicate where they would place the ball in the opposing half. The results showed the tactical preference of players to place more balls on a left-handed opponent's mostly stronger forehand side compared with when faced with a right-hander. In the second study, 54 professional tennis matches involving right- and left-handers were analysed with respect to ball placement frequencies on the opponent's backhand side. Significantly fewer balls were hit to the backhand side of a left-handed opponent, thus replicating the findings of Study 1 in on-court situations. Both studies indicate players' preference to place shots to their right irrespective of their opponent's handedness. Findings support the assumption that left-handers might enjoy a strategic advantage in tennis.

Motor competence is not enough: Handedness does not facilitate visual anticipation of same-handed action outcome.

Visual understanding of others performing an action depends on both an observer's visual and motor experience with that action. With regard to visual anticipation of lateralized action outcome in one-on-one confrontative situations, however, the particular role of motor experience is poorly understood. Here, we considered handedness to test the laterality-specific contribution of visual and motor experience to action outcome anticipation. In two experiments, 55 left- and 114 right-handed handball players predicted the outcome (Exp. 1: throw direction; Exp. 2: type of throw) of videos showing left- and right-handed penalty-throws viewed from a goalkeeper's perspective. Analyses reveal that left- and right-handed participants performed similarly and had more difficulties anticipating the outcome direction, but not type of throw, of left- compared to right-handed penalties. Thus, albeit left- and right-handers differ in their lateralized motor experience, this does not seem to be sufficient to facilitate visual anticipation of same-handed action outcome. Instead, findings lend further support to the specificity of perceptual learning and visual experience arising from both left- and right-handers' predominant exposure to more common right-handed movements.

On the Influence of Action Preference on Female Players' Gaze Behavior During Defense of Volleyball Attacks.

Knowledge of an opponent's action preference may affect visual anticipation of their action outcome. Specifically, if an opponent acts according to their purported preference, anticipation may be facilitated. Conversely, if an opponent does not act according to their purported preference, anticipation may be unaffected or even harmed. The underlying perceptual-cognitive mechanisms of that effect, however, remain unclear. Here we tested the hypothesis that players might change their gaze behavior once provided with preference information. To this end, 27 female volleyball players anticipated the direction of attacks in two test blocks with 40 videos each. Videos were shown on a large screen and stopped 240 ms prior to hand-ball-contact. Participants simulated defensive reaction while their gaze was recorded using a mobile eye-tracker. One female attacker directed 75% of shots diagonally (25% longline), while another female attacker distributed shots equally to both directions. After block one, half of the participants were informed that either both attackers preferred diagonal shots in 75% of occasions (group preferred) or that both attackers distributed shots equally across directions (group non-preferred). Analysis of decision behavior (i.e., proportion of diagonal decisions), but not prediction accuracy (i.e., proportion of correct predictions), revealed that those instructions led both groups decide differently according to the purported preferences from block 1 to block 2. Analysis of gaze behavior did not reveal group-specific effects across blocks or attackers with/-out action preference. Findings underline the influence of contextual information on anticipation, but they leave open whether the availability of contextual information similarly affects gaze behavior.

The Influence of Exercise-Induced Fatigue on Inter-Limb Asymmetries: a Systematic Review.

BACKGROUND: Non-contact injuries such as anterior cruciate ligament ruptures often occur during physical load toward the end of a match. This is ascribed to emerging processes due to exercise-induced fatigue. Moreover, non-contact injuries often occur during dynamic actions such as landing or cutting movements. Inter-limb asymmetries are suggested as one possible cause for those injuries based on findings indicating that asymmetries between limbs are associated with a higher injury risk. Hence, assessing inter-limb asymmetry during physical load in the condition of exercise-induced fatigue is warranted to identify potentially relevant precursors for non-contact injuries. OBJECTIVE: The objective of this study was to overview the current state of evidence concerning the influence of exercise-induced fatigue on inter-limb asymmetries through a systematic review. METHODS: A systematic literature search was conducted using the databases Web of Science, Scopus, PubMed, SURF, and SPONET to identify studies that assessed inter-limb asymmetries of healthy people, calculated with an asymmetry equation, before and after, or during a loading protocol. RESULTS: Thirteen studies were included in the systematic review. The loading protocols involved running, race walking, jumping, squatting, soccer, rowing, and combinations of different exercises. Moreover, different tasks/procedures were used to assess inter-limb asymmetries, e.g., squats, single-leg countermovement jumps, gait analysis, or isokinetic strength testing. The results seem to depend on the implemented loading protocol, the tasks/procedures, and the measured parameters. CONCLUSIONS: Future research needs more systematization and consistency, assessing the effect of exercise-induced fatigue on inter-limb asymmetries. Moreover, the emergence of inter-limb asymmetries should be regarded in the context of sport-specific movements/tasks. Testing before, after, and during a physical loading protocol is advisable to consider the influence of exercise-induced fatigue on sport-specific tasks and to identify the possible mechanisms underlying load-dependent inter-limb asymmetries with regard to risk of non-contact injury.

Extending Research on Deception in Sport - Combining Perception and Kinematic Approaches.

The spatio-temporal demands of many high performance sport contexts require a strategic interplay between anticipation from early kinematic cues and the appropriate movement strategy. Despite the importance of the interaction between observer and deceiver in these contexts, this dyad is usually considered separately (i.e., from perceptual-cognitive or kinematic perspectives). The present approach proposes a consolidation of perceptual-cognitive and kinematic perspectives into a dyad of deception that focuses on the interplay between opposing actors within antagonistic contexts. A framework is proposed for analyzing movement deception within this dyad. Applying a functional approach, the deceptive act is positioned as a means of optimally solving an antagonistic performance task with high spatio-temporal demands. The framework involves three elements: first, the context of the movement deception is evaluated relative to the constraints imposed by the athlete, object, and deceptive content. Together, these constraints generate a range of potential kinematic options for movement deception. Second, movement deception is determined by the spatio-temporal constraints of the original context. More simply, misleading information is only useful if it mimics elements of the genuine movement. Third, the framework emphasizes targeting the spatio-temporal interplay as well as differentiating between active and co(ntra)-active movement deception. Our goal with this framework is to supplement movement deception research by providing a conceptional context that can be applied across sports.

Anticipation in sport.

Anticipation has become an increasingly important research area within sport psychology since its infancy in the late 1970s. Early work has increased our fundamental understanding of skilled anticipation in sports and how this skill is developed. With increasing theoretical and practical insights and concurrent technological advancements, researchers are now able to tackle more detailed questions with sophisticated methods. Despite this welcomed progress, some fundamental questions and challenges remain to be addressed, including the (relative) contributions of visual and motor experience to anticipation, intraindividual and interindividual variation in gaze behaviour, and the impact of non-kinematic (contextual or situational) information on performance and its interaction with advanced kinematic cues during the planning and execution of (re)actions in sport. The aim of this opinion paper is to shortly sketch the state of the art, and then to discuss recent work that has started to systematically address open challenges thereby inspiring promising future routes for research on anticipation and its application in practice.