An examination of perceptual-motor recalibration in a 1-vs-1 anticipation test.

This study examined the processes of perceptual-motor calibration/recalibration of defensive football players in a 1-vs-1 scenario. Ankle weights were used to reduce the acceleration capabilities of players performing an anticipation test, with the aim being to examine the player's response to the disturbance in terms of when movement was initiated and the impact on the mechanisms that underpinned anticipation, namely gaze behaviour. The ankle weights disturbed the perceptual-motor system and players initiated movement significantly earlier in the 1-vs-1 anticipation test. Analyses of perceptual-motor calibration/recalibration revealed that players acted closer to their maximal action capabilities prior to the addition of ankle weights, which negatively influenced the scaling of action capabilities. Moreover, players were unable to recalibrate whilst wearing ankle weights. However, following the withdrawal of the ankle weights, players were able to recalibrate within 11-15 trials. Players did not adapt gaze behaviour as a result of the disturbance being placed on the perceptual-motor system, but task familiarization resulted in more efficient eye movements. The results of this study show the importance of providing players the opportunity to "scale" action to perceptual information.

The spatiotemporal control of expert tennis players when returning first serves: A perception-action perspective.

The aim of the current experiment was to examine the spatiotemporal control of expert tennis players while executing first service returns within a representative experimental setting. We recruited and tested 12 male expert tennis players in hard courts. A comprehensive analysis of the timing (eleven temporal variables analysed at 300 Hz) and performance success of the return actions were carried out, while simultaneously considering task constraints such as the accuracy and the speed of the serves. Temporal organisation of return actions were scaled relative to the server's racket-ball contact (5 ms), an adaptation of fly-time of the split-step, which resulted in consistent landings (133 ms), and initiation of lateral movements towards the ball - with no response errors - after the server's stroke (around 177 ms). Poorer returns occurred when responding to accurate serves accompanied by late trunk movements towards the ball. Returners scaled the timing of the response to the unfolding action of the serve in order to support both spatial and temporal accuracy. These novel findings highlight the significance of the study of fast-ball sports in representative settings and offer further detail on the spatiotemporal control of skilful perception-action.

Exploring to learn and learning to explore.

In respect to ecological psychology processes of attunement and calibration, this critical review focusses on how exploratory behaviors may contribute to skilled perception and action, with particular attention to sport. Based on the theoretical insights of Gibson (The senses considered as perceptual systems, Houghton Mifflin, Boston, 1966) and Reed (Encountering the world: Toward an ecological psychology, Oxford University Press, New York, 1996), exploratory and performatory actions have been differentiated in numerous experiments to study the perception of opportunities of action. The distinction between exploratory and performatory actions has informed the study of infant behavior in developmental psychology. In the current article, we highlight limitations with this distinction in the study of sports performers. We propose that a dynamic view of exploratory behavior would reveal how individuals develop exploratory activity that generates information about the fit between environmental properties and action capabilities. In this aim, practitioners should: (1) give learners the opportunity to safely develop exploratory behaviors even when they act outside their action boundary; and (2) guide learners to search for more reliable information to develop exploratory behaviors that would enhance the transfer of skills to various performance contexts.

Cognitive performance is associated with cerebral oxygenation and peripheral oxygen saturation, but not plasma catecholamines, during graded normobaric hypoxia.

NEW FINDINGS: What is the central question of this study? What are the mechanisms responsible for the decline in cognitive performance following exposure to acute normobaric hypoxia? What are the main findings and their importance? We found that (1) performance of a complex central executive task (n-back) was reduced at FIO2 0.12; (2) there was a strong correlation between performance of the n-back task and reductions in SpO2 and cerebral oxygenation; and (3) plasma adrenaline, noradrenaline, cortisol and copeptin were not correlated with cognitive performance. ABSTRACT: It is well established that hypoxia impairs cognitive function; however, the physiological mechanisms responsible for these effects have received relatively little attention. This study examined the effects of graded reductions in fraction of inspired oxygen ( FIO2 ) on oxygen saturation ( SpO2 ), cerebral oxygenation, cardiorespiratory variables, activity of the sympathoadrenal system (adrenaline, noradrenaline) and hypothalamic-pituitary-adrenal axis (cortisol, copeptin), and cognitive performance. Twelve healthy males [mean (SD), age: 22 (4) years, height: 178 (5) cm, mass: 75 (9) kg, FEV1 /FVC ratio: 85 (5)%] completed a four-task battery of cognitive tests to examine inhibition, selective attention (Eriksen flanker), executive function (n-back) and simple and choice reaction time (Deary-Liewald). Tests were completed before and following 60 min of exposure to FIO2 0.2093, 0.17, 0.145 and 0.12. Following 60 min of exposure, response accuracy in the n-back task was significantly reduced in FIO2 0.12 compared to baseline [82 (9) vs. 93 (5)%; P < 0.001] and compared to all other conditions at the same time point [ FIO2 0.2093: 92 (3)%; FIO2 0.17: 91 (6)%; FIO2 0.145: 85 (10)%; FIO2 12: 82 (9)%; all P < 0.05]. The performance of the other tasks was maintained. Δaccuracy and Δreaction time of the n-back task was correlated with both Δ SpO2 [r(9) = 0.66, P < 0.001 and r(9) = -0.36, P = 0.037, respectively] and Δcerebral oxygenation [r(7) = 0.55, P < 0.001 and r(7) = -0.38, P = 0.045, respectively]. Plasma adrenaline, noradrenaline, cortisol and copeptin were not significantly elevated in any condition or correlated with any of the tests of cognitive performance. These findings suggest that reductions in peripheral oxygen saturation and cerebral oxygenation, and not increased activity of the sympathoadrenal system and hypothalamic-pituitary-adrenal axis, as previously speculated, are responsible for a decrease in cognitive performance during normobaric hypoxia.

Relationship between split-step timing and leg stiffness in world-class tennis players when returning fast serves.

This study investigated split-step timing when returning serves and whether this timing is related to neuromechanical capabilities in world-class tennis players. In Experiment 1, the split-step timing of four groups of world-class players (male and female ATP/WTA seniors, and ITF juniors) was measured on court when returning serves of the same level players. The four groups initiated the split-step at a similar time, starting around the time ball-racket contact in the serve stroke and landed when early ball-flight information was available. In Experiment 2, the neuromechanical capabilities (leg stiffness and vertical jump performance) of a group of world-class players and three groups of less-skilled tennis players were examined. The results showed an increase in leg stiffness with an increase in the level of expertise. A cross-experiment analysis in world-class male players (ATP/ITF, n = 10) revealed that the timing of initial foot movement was significantly correlated with the leg stiffness (r2 = 0.54), with later lateral step after the serve in the players who had higher stiffness. The findings support the hypothesis that world-class tennis players adapt perceptual-motor control on the basis of their neuromechanical capabilities and maximise the time before initiating their interceptive action to rely on more reliable information.

Nothing magical: pantomimed grasping is controlled by the ventral system.

In a recent amendment to the two-visual-system model, it has been proposed that actions must result in tactile contact with the goal object for the dorsal system to become engaged (Whitwell et al., Neuropsychologia 55:41-50, 2014). The present study tested this addition by assessing the use of allocentric information in normal and pantomime actions. To this end, magicians, and participants who were inexperienced in performing pantomime actions made normal and pantomime grasps toward objects embedded in the Müller-Lyer illusion. During pantomime grasping, a grasp was made next to an object that was in full view (i.e., a displaced pantomime grasping task). The results showed that pantomime grasps took longer, were slower, and had smaller hand apertures than normal grasping. Most importantly, hand apertures were affected by the illusion during pantomime grasping but not in normal grasping, indicating that displaced pantomime grasping is based on allocentric information. This was true for participants without experience in performing pantomime grasps as well as for magicians with experience in pantomiming. The finding that the illusory bias is limited to pantomime grasping and persists with experience supports the conjecture that the normal engagement of the dorsal system's contribution requires tactile contact with a goal object. If no tactile contact is made, then movement control shifts toward the ventral system.

Looking further! The importance of embedding visual search in action.

A unified account of visual search in complex everyday environments requires additional deliberations on the functional grounding of Hulleman & Olivers' (H&O's) functional viewing field (FVF) model. Their model can accommodate exploitation of information that is distributed across the immediate environment. Yet the differences in search between genuinely interacting in the environment and merely watching it should challenge researchers to look further.

The development of a method for identifying penalty kick strategies in association football.

Penalty takers in association football adopt either a keeper-independent or a keeper-dependent strategy, with the benefits of the keeper-independent strategy presumed to be greater. Yet, despite its relevance for research and practitioners, thus far no method for identifying penalty kick strategies has been available. To develop a validated and reliable method, Experiment 1 assessed characteristics that observers should use to distinguish the two strategies. We asked participants to rate 12 characteristics of pre-recorded clips of kicks of penalty takers that used either a keeper-independent or keeper-dependent strategy. A logistic regression model identified three variables (attention to the goalkeeper, run-up fluency and kicking technique) that in combination predicted kick strategy in 92% of the penalties. We used the model in Experiment 2 to analyse prevalence and efficacy of both the strategies for penalty kicks in penalty shoot-outs during FIFA World Cups (1986-2010) and UEFA Football Championships (1984-2012). The keeper-independent strategy was used much more frequently (i.e., 78-86%) than the keeper-dependent strategy, but successes did not differ. Penalty takers should use both the strategies to be less predictable. Goalkeepers can use the developed model to improve their chances to succeed by adjusting their behaviour to penalty takers' preferred penalty kick strategy.

Decision-Making in Action: How International-Level Professional Football Players Gain an Advantage.

Understanding how both visual and contextual in-game information influences player's attempts to gain an advantage over their opponent is key to understanding skilled decision-making in fast-ball sports. In the present study, we conducted semi-structured interviews with 15 male professional football players to explore their reported behaviours and perspectives on their in-game decision-making and the ways in which they adapt to gain an advantage over their opponent. Professional players who have competed internationally at either Under 17, Under 19, Under 21, or senior level took part in semi-structured interviews. The data were analysed using reflexive thematic analysis (Braun et al., 2016; Braun & Clarke, 2019) which generated four higher-order themes about players reported behaviours and perspectives on their decision-making and ways of gaining an advantage: (i) being "unpredictable"; (ii) option generation and invitation, comprising two sub-themes: (iia) generating and realising options in action; and (iib) act on what invites you in the moment; (iii) anticipation and awareness; and (iv) dictating and controlling the game. A key finding was that players attempts to gain an advantage were largely grounded in the aim of 'being unpredictable' through the use of deception and disguise, as well as deliberate manipulation of action sequences in order to make their actions 'hard to read'. A further important finding was that players do not always seek a universal optimal decision, as their individual action capabilities influence their available options. These findings have important implications for the assessment of decision-making performance in future empirical research.

Henri Cochet's theory of angles in tennis (1933) reveals a new facet of anticipation.

In this study, we tested the theory of angles that was proposed almost a century ago by the tennis player Henri Cochet. This theory proposes that expert tennis players should position themselves on the bisector of the angle of the opponent's possibilities in order to optimize shot return, suggesting a geometric occupation of the court relative to the opponent's affordances; namely what he/she is capable of doing. We tested this hypothesis by analysing player and ball positioning data from professional tennis matches recorded with a Hawk-Eye system. We compared this hypothesis with two alternative computational and probabilistic hypotheses which would consist in positioning oneself on the average or the median of the shots usually played from a given location. The results show that expert tennis players apply the principles of the theory of angles and thus confirm Henri Cochet's intuition. That is, for lateral court positioning, a geometric strategy is deemed optimal by expert players. It also appears that the more experienced the players are, the more precise their application of this strategy becomes.

The effects of sleep deprivation, acute hypoxia, and exercise on cognitive performance: A multi-experiment combined stressors study.

INTRODUCTION: Both sleep deprivation and hypoxia have been shown to impair executive function. Conversely, moderate intensity exercise is known to improve executive function. In a multi-experiment study, we tested the hypotheses that moderate intensity exercise would ameliorate any decline in executive function after i) three consecutive nights of partial sleep deprivation (PSD) (Experiment 1) and ii) the isolated and combined effects of a single night of total sleep deprivation (TSD) and acute hypoxia (Experiment 2). METHODS: Using a rigorous randomised controlled crossover design, 12 healthy participants volunteered in each experiment (24 total, 5 females). In both experiments seven executive function tasks (2-choice reaction time, logical relations, manikin, mathematical processing, 1-back, 2-back, 3-back) were completed at rest and during 20 min semi-recumbent, moderate intensity cycling. Tasks were completed in the following conditions: before and after three consecutive nights of PSD and habitual sleep (Experiment 1) and in normoxia and acute hypoxia (FIO2 = 0.12) following one night of habitual sleep and one night of TSD (Experiment 2). RESULTS: Although the effects of three nights of PSD on executive functions were inconsistent, one night of TSD (regardless of hypoxic status) reduced executive functions. Significantly, regardless of sleep or hypoxic status, executive functions are improved during an acute bout of moderate intensity exercise. CONCLUSION: These novel data indicate that moderate intensity exercise improves executive function performance after both PSD and TSD, regardless of hypoxic status. The key determinants and/or mechanism(s) responsible for this improvement still need to be elucidated. Future work should seek to identify these mechanisms and translate these significant findings into occupational and skilled performance settings.

Training for "Worst-Case" Scenarios in Sidestepping: Unifying Strength and Conditioning and Perception-Action Approaches.

Sidesteps can impose high demands on the knee joint and lead to non-contact anterior cruciate ligament (ACL) injuries. Understanding how different constraints shape an athlete's movement strategy and the associated joint demands can help design training interventions to increase injury resilience. Motor capacities, such as muscular strength and power, act as boundaries for the safe execution of perceptual-motor skills and co-determine the emergence of unique movement strategies. Increasing single- and multi-joint strength enables a broader solution space for movement strategies and increases load tolerance. Manipulating task constraints during sidesteps can be used in the training process to systematically expose athletes to increasing demands (on the knee joint or any joint or structure) in preparation for "worst-case" scenarios. In particular, the type and timing of information available influence the preparation time, subsequently affecting the movement strategy and the associated magnitude of external knee joint loading (e.g., knee valgus moment). While an athlete's perceptual-cognitive skills contribute to the preparation time during in situ scenarios, attempts to further improve those skills with the aim of increasing athlete preparation time prior to "worst-case" scenarios are yet to demonstrate conclusive evidence of transfer to on-field situations. Therefore, in the current article, we reflect on the impact of different interacting constraints that influence the execution of sidesteps during in situ scenarios and impose high demands on the knee joint. Subsequently, we discuss how an integrated perspective, drawing on knowledge and perspectives from strength and conditioning and perception-action, may enhance an athlete's ability to withstand "worst-case" scenarios and adapt to perform varied movement executions when sidestepping.

The visual control of locomotion when stepping onto moving surfaces: A comparison of younger and older adults.

Stepping between static and moving surfaces presents a locomotor challenge associated with increased injury frequency and severity in older adults. The current study evaluates younger and older adults' behaviours when overcoming challenges sampling moving walkway and escalator environments. Twelve younger adults (18-40 years, Male = 8) and 15 older adults (60-81 years, Male = 5) were examined using an integration of optoelectronic motion capture and mobile eye-tracking. Participants were investigated approaching and stepping onto a flat conveyor belt (static or moving; with or without surface (demarcation) lines). Specifically, the four conditions were: (i) static surface without demarcation lines; (ii) static surface with demarcation lines; (iii) moving surface without demarcation lines; and (iv) moving surface with demarcation lines. A two (age group) x two (surface-condition) x two (demarcation-condition) linear mixed-model revealed no main or interaction effects (p > .05) for perturbation magnitude, indicating participants maintained successful locomotion. However, different adaptive behaviours were identified between conditions with moving and accuracy demands (e.g., moving surfaces increased step length, demarcations reduced step length). Between subject effects identified differences between age groups. Older adults utilised different behaviours, such as earlier gaze transfer from the final approach walkway step location. Overall, the current study suggests that adaptive behaviours emerge relative to the environment's specific demands and the individual's action capabilities.

The effectiveness of penalty takers' deception: A scoping review.

Attackers are supposed to take advantage of producing deceptive actions in competitive ball sports, particularly in penalty situations. We conducted a scoping review of the experimental literature to scrutinize whether penalty takers do indeed benefit from using deceptive actions in penalty situations, especially by increasing the likelihood to score a goal. Studies using video-based and in-situ tasks in which soccer and handball goalkeepers try to save a penalty were evaluated. Results showed that penalty takers' manipulation of spatial information available to the goalkeeper during deception (i.e., by using misleading and/or disguising actions) is less effective in in-situ than video-based studies. We argue that this difference occurs because goalkeepers adapt differently to the spatiotemporal constraints in the video-based and in-situ tasks. Goalkeepers appear to prioritize picking up spatial information in video-based tasks while prioritizing temporal information in-situ tasks. Therefore, the manipulation of spatial information appears to be less effective in the more representative in-situ studies than in video-based studies. In order to deceive, penalty takers are advised to manipulate temporal information during on-field penalty situations.

LoCoMoTe - a Framework for Classification of Natural Locomotion in VR by Task, Technique and Modality.

Virtual reality (VR) research has provided overviews of locomotion techniques, how they work, their strengths and overall user experience. Considerable research has investigated new methodologies, particularly machine learning to develop redirection algorithms. To best support the development of redirection algorithms through machine learning, we must understand how best to replicate human navigation and behaviour in VR, which can be supported by the accumulation of results produced through live-user experiments. However, it can be difficult to identify, select and compare relevant research without a pre-existing framework in an ever-growing research field. Therefore, this work aimed to facilitate the ongoing structuring and comparison of the VR-based natural walking literature by providing a standardised framework for researchers to utilise. We applied thematic analysis to study methodology descriptions from 140 VR-based papers that contained live-user experiments. From this analysis, we developed the LoCoMoTe framework with three themes: navigational decisions, technique implementation, and modalities. The LoCoMoTe framework provides a standardised approach to structuring and comparing experimental conditions. The framework should be continually updated to categorise and systematise knowledge and aid in identifying research gaps and discussions.

Nonverbal behavior in soccer: the influence of dominant and submissive body language on the impression formation and expectancy of success of soccer players.

In the present article, we investigate the effects of specific nonverbal behaviors signaling dominance and submissiveness on impression formation and outcome expectation in the soccer penalty kick situation. In Experiment 1, results indicated that penalty takers with dominant body language are perceived more positively by soccer goalkeepers and players and are expected to perform better than players with a submissive body language. This effect was similar for both video and point-light displays. Moreover, in contrast to previous studies, we found no effect of clothing (red vs. white) in the video condition. In Experiment 2, we used the implicit association test to demonstrate that dominant body language is implicitly associated with a positive soccer player schema whereas submissive body language is implicitly associated with a negative soccer player schema. The implications of our findings are discussed with reference to future implications for theory and research in the study of person perception in sport.

Evaluating the integration of eye-tracking and motion capture technologies: Quantifying the accuracy and precision of gaze measures.

Integrating mobile eye tracking and optoelectronic motion capture enables point of gaze to be expressed within the laboratory co-ordinate system and presents a method not commonly applied during research examining dynamic behaviors, such as locomotion. This paper examines the quality of gaze data collected through the integration. Based on research suggesting increased viewing distances are associated with reduced data quality; the accuracy and precision of gaze data as participants (N = 11) viewed floor-based targets at distances of 1-6 m was investigated. A mean accuracy of 2.55 ± 1.12° was identified, however, accuracy and precision measures (relative to targets) were significantly (p < .05) reduced at greater viewing distances. We then consider if signal processing techniques may improve accuracy and precision, and overcome issues associated with missing data. A 4th-order Butterworth lowpass filter with cut-off frequencies determined via autocorrelation did not significantly improve data quality, however, interpolation via Quintic spline was sufficient to overcome gaps of up to 0.1 s. We conclude the integration of gaze and motion capture presents a viable methodology in the study of human behavior and presents advantages for data collection, treatment, and analysis. We provide considerations for the collection, analysis, and treatment of gaze data that may help inform future methodological decisions.

Maximising Grip on Deception and Disguise: Expert Sports Performance During Competitive Interactions.

Expert performers in fast-ball and combat sports continuously interact with their opponents and, if they are to be successful, adapt behaviour in order to gain an advantage. For example, disguise and deception are recognised as skilful behaviours that are employed to disrupt an opponent's ability to successfully anticipate their actions. We contend that such skilled behaviour unfolds during the interaction between opposing players, yet typical research approaches omit and/or artificially script these interactions. To promote the study of skilled behaviour as it emerges during competitive interactions, we offer an account informed by contemporary ecological perspectives for shaping investigation into how deception and disguise can be used to gain an advantage over an opponent and the challenges it poses to anticipation. We propose that each player attempts to develop maximum grip on the interaction through exploiting information across multiple timescales to position themselves as to facilitate openness to relevant affordances. The act of deception can be understood as offering a misleading affordance that an opponent is invited to act on, imposing a significant challenge to an opponent's ability to attain grip by manipulating the information available. Grounded in our ecological perspective, we emphasise the need for future investigation into: (1) the role of disguise for disrupting anticipation; (2) how deception can be employed to gain an advantage by manipulating information on multiple timescales, before detailing; (3) how opposing performers go beyond merely exploiting information and actively elicit information to deal with deception and disguise during an interaction.

Visual control during climbing: Variability in practice fosters a proactive gaze pattern.

In climbing, the visual system is confronted with a dual demand: controlling ongoing movement and searching for upcoming movement possibilities. The aims of the present research were: (i) to investigate the effect of different modes of practice on how learners deal with this dual demand; and (ii) to analyze the extent this effect may facilitate transfer of learning to a new climbing route. The effect of a constant practice, an imposed schedule of variations and a self-controlled schedule of variations on the gaze behaviors and the climbing fluency of novices were compared. Results showed that the constant practice group outperformed the imposed variability group on the training route and the three groups climbing fluency on the transfer route did not differ. Analyses of the gaze behaviors showed that the constant practice group used more online gaze control during the last session whereas the imposed variability group relied on a more proactive gaze control. This last gaze pattern was also used on the transfer route by the imposed variability group. Self-controlled variability group displayed more interindividual differences in gaze behaviors. These findings reflect that learning protocols induce different timing for gaze patterns that may differently facilitate adaptation to new climbing routes.

The influence of skill and task complexity on perception of nested affordances.

This study investigated how skill level and task complexity influence the calibration of perception-action and particularly how close an individual acts relative to his or her maximal action capabilities. Complexity was manipulated between two (Touch, Grasp) and more than two (Removing, Moving Up) nested affordance conditions. For all conditions, we examined whether advanced climbers had greater maximal action capabilities than intermediate climbers or whether they better scaled their action (i.e., acted nearer to their maximal action capabilities) or both. Eleven intermediate and 11 advanced male climbers were first asked to estimate the maximum distance that they could reach a climbing hold. The hold was moved along a slide and fixed once requested by the participant; subsequently, the distance to the starting hold was measured. After each estimation, the participant was required to execute the climbing action. After four estimation-action trials in each of the four conditions, the maximal action capability (i.e., actual maximal reaching distance) was determined. Advanced climbers demonstrated greater actual maximal reaching distances than intermediate climbers for all conditions, but they only estimated greater maximal reaching distances for the more complex conditions, which featured more than two nested affordances. When estimated maximal reaching distances were scaled to actual maximal reaching distances, advanced climbers did not differ from intermediate climbers for any condition, and there were no differences between conditions. Our findings indicate that expertise was a function of greater action capabilities, but not due to the accuracy of calibration.