Caffeine Gum Improves Reaction Time but Reduces Composure Versus Placebo During the Extra-Time Period of Simulated Soccer Match-Play in Male Semiprofessional Players.

This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p < .01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p < .01). Caffeine gum did not influence any other variables (p > .05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions.

Effect of Intermittent Exercise on Performance in 3D Multiple Objects Tracking in Children, Young and Older Adults-A Pilot Study.

BACKGROUND: Although an extensive body of literature is trying to verify the acute effects of exercise, findings are highly contradictory due to many different study protocols. The number of studies using an intermittent exercise (IE) protocol is limited, especially with regard to comparison across the life span. We examined whether the effects of a HIIE protocol on performance in a perceptual-cognitive task (NeuroTracker® (NT)) differed between children, young adults, and older adults to address this gap. METHODS: A total of 36 participants participated in the present study: 12 children (CH, 6 females, 9.83 ± 1.19 years), 12 young adults (YA, 6 females, 23.5 ± 3.55 years), and 12 older adults (OA, 4 females, 66.92 ± 4.08 years). The IE treadmill protocol used in the present study consisted of eleven 30-second intervals at 90% VO2max, interspersed with 2-minute active recovery periods at 50% VO2max. Before and during this exercise protocol, three series of the NeuroTracker® task were performed after 5, 15, and 25 minutes. RESULTS: We observed a significant main effect time and a significant main effect group regarding absolute NT scores and progression during IE. YA had significantly higher absolute NT scores than CH and OA. The normalized perceptual-cognitive task progression was observed in OA and YA but not in CH. YA, in particular, showed progression in the NT performance during IE. CONCLUSIONS: The present study confirmed previous findings on age-related differences in NT performance. Based on these findings, the effects of different exercise protocols (e.g., continuous vs. intermittent) seem to be a worthwhile subject for future investigations. Normalized speed thresholds should best capture improvement differences between groups to compare results across studies better, as pre-test values are taken as the baseline.

Does anticipation of penalty kicks in soccer transfer across similar and dissimilar sports?

The aim of the present study was to examine whether anticipation skill associated with penalty-kick scenarios is sport-specific, or whether it transfers between sports that have similar elements. A shortened participation history questionnaire was used to identify 97 soccer players, 47 invasion sport players (e.g., rugby), and 72 other sport players (e.g., swimming), as well as skill level (hours of engagement/competition level). These participants completed a video-based temporal occlusion anticipation test that required them to select the destination of the ball across a series of soccer penalty scenarios. Results indicated that the skilled soccer players were more accurate than the skilled and less-skilled invasion sport players and skilled and less-skilled other sport players. Skilled soccer players were also more accurate than the less-skilled soccer players, with less-skilled soccer players exhibiting similar accuracy to both the skilled and less-skilled invasion sport and other sport players indicating that processes associated with anticipation of penalty kicks may be specific to their sport.

Basketball videos presented on a computer screen appear slower than in virtual reality.

Decision-making skills are essential to successful performance. To train them, coaches frequently use video replays to show their athletes how to best respond when facing specific situations. Recently, it has been shown that presenting the videos in virtual reality (VR) led to enhanced transfer, from the laboratory to the playing field, compared to when the videos were presented on a standard computer screen (CS). Interestingly, although the videos were identical, many participants informally reported that the VR videos felt accelerated compared to those they usually see on television. Here, we tested this claim by having varsity-level basketball players perform a decision-making task concomitantly with a playback speed estimation task. All participants observed the same video clips in the VR and CS conditions, and the video clips were either presented at their normal speed or had been accelerated or decelerated by 10%. Our results revealed that participants perceived the VR videos as significantly faster than the CS videos (mean perceived playback speed of 100.7% ± 2.35% and 94.9% ± 2.24%, respectively). This difference was, however, caused by the CS videos appearing slower than they truly were. Our results indicate that VR videos appear immune to the speed underestimation frequently reported with CS videos.

Skill-Based Differences in the Detection and Utilization of Opponent Action Preferences Following Increasing Exposure and Changes in Tendencies.

We examined skill-based differences in the detection and utilization of contextual information over a period of increasing exposure to an opponent's action preferences in soccer. Moreover, we investigated the ability of athletes to adapt to changes in these action preferences over time. In an initial detection phase, the attacking opponent demonstrated a proclivity to either pass or dribble, with these preferences being reversed in a subsequent adaptation phase of the same length. Skilled soccer players showed superior anticipation accuracy across both phases compared with less-skilled counterparts. The skilled participants significantly enhanced their performance over both phases, despite a significant drop in performance immediately following the change in opponent action preferences. In contrast, the less-skilled group only improved over the detection phase. Gaze data revealed that the skilled participants fixated more on kinematically relevant areas, compared with the less-skilled group, and increased the time spent fixating the player "off the ball" following greater volumes of exposure. Our novel findings elaborate on how skilled performers use both action preferences and motion information to anticipate an opponent's impending actions in sport.

Howzat! Expert umpires use a gaze anchor to overcome the processing demands of leg before wicket decisions.

Cricket umpires are required to make high-pressure, match-changing decisions based on multiple complex information sources under severe temporal constraints. The aim of this study was to examine the decision-making and perceptual-cognitive differences between expert and novice cricket umpires when judging leg before wicket (LBW) decisions. Twelve expert umpires and 19 novice umpires were fitted with an eye-tracker before viewing video-based LBW appeals. Dependent variables were radial error (cm), number of fixations, average fixation duration (ms), final fixation duration (ms), and final fixation location (%). Expert umpires were significantly more accurate at adjudicating on all aspects of the LBW law, compared to the novice umpires (p < .05). The expert umpires' final fixation prior to ball-pad contact was directed significantly more towards the stumps (p < .05), whereas the novice umpires directed their final fixation significantly more towards a good length (p < .05). These data suggest that expert umpires utilize specialized perceptual-cognitive skills, consisting of a gaze anchor on the stumps in order to overcome the processing demands of the task. These data have implications for the training of current and aspiring umpires in order to enhance the accuracy of LBW decision-making across all levels of the cricketing pyramid.

The development of perceptual-cognitive skills in youth volleyball players.

In many sports, elite players outperform novices on tests for perceptual-cognitive skills, such as anticipation, decision-making and pattern recall. However, the developmental trajectory of these perceptual-cognitive skills has received limited attention. Therefore, this study examined the development of anticipation, decision-making and pattern recall in 202 female volleyball players aged between 7 and 26 years old. Participants were categorized into six age groups: U9, U11, U13, U15, U17 and Seniors. Using a video-based occlusion protocol, we assessed participants' ability to predict pass direction, decide the most optimal attack zone, or recall the opponents' defence positions. The results demonstrated that U17 and adult players had superior accuracy and shorter response times than younger players on all three tests. Notably, U9 players performed worse than older players on all tests. Binomial distributions showed that decision-making was above chance for U17 players and adults, whereas anticipation was above chance for almost all players. Our findings indicate that age-related improvements of perceptual-cognitive skills are evident at 11 years old. However, decision-making seems to develop considerably later than anticipation and pattern recall, suggesting different developmental trajectories for the different perceptual-cognitive skills. Longitudinal research regarding the development of perceptual-cognitive skills and their underlying mechanisms is warranted, as this could have important implications for talent detection and development.

Assessing Visual Exploratory Activity of Athletes in Virtual Reality Using Head Motion Characteristics.

Maximizing performance success in sports is about continuous learning and adaptation processes. Aside from physiological, technical and emotional performance factors, previous research focused on perceptual skills, revealing their importance for decision-making. This includes deriving relevant environmental information as a result of eye, head and body movement interaction. However, to evaluate visual exploratory activity (VEA), generally utilized laboratory settings have restrictions that disregard the representativeness of assessment environments and/or decouple coherent cognitive and motor tasks. In vivo studies, however, are costly and hard to reproduce. Furthermore, the application of elaborate methods like eye tracking are cumbersome to implement and necessitate expert knowledge to interpret results correctly. In this paper, we introduce a virtual reality-based reproducible assessment method allowing the evaluation of VEA. To give insights into perceptual-cognitive processes, an easily interpretable head movement-based metric, quantifying VEA of athletes, is investigated. Our results align with comparable in vivo experiments and consequently extend them by showing the validity of the implemented approach as well as the use of virtual reality to determine characteristics among different skill levels. The findings imply that the developed method could provide accurate assessments while improving the control, validity and interpretability, which in turn informs future research and developments.

Context Affects Quiet Eye Duration and Motor Performance Independent of Cognitive Effort.

Extensive literature has shown the effect of "quiet eye" (QE) on motor performance. However, little attention has been paid to the context in which tasks are executed (independent of anxiety) and the mechanisms that underpin the phenomenon. Here, the authors aimed to investigate the effects of context (independent of anxiety) on QE and performance while examining if the mechanisms underpinning QE are rooted in cognitive effort. In this study, 21 novice participants completed golf putts while pupil dilation, QE duration, and putting accuracy were measured. Results showed that putting to win was more accurate compared with the control (no context) condition, and QE duration was longer when putting to win or tie a hole compared with control. There was no effect of context on pupil dilation. Results suggest that, while the task was challenging, performance scenarios can enhance representativeness of practice without adding additional load to cognitive resources, even for novice performers.

Seemingly Uninvolved Players' Impact on Assistant Referees' Offside Decisions.

Most studies on offside decision making in soccer have not addressed rather simplistic situational probabilities like the number of players involved in an offside situation. In three studies (one observational and two experimental), the authors tried to assess whether the number of players close to the offside situation can predict the quality of offside decision making. In all three studies, they found that the presence of additional players negatively affected the percentage of correct decisions. The exact relationship between the number of players and the decrease in decision-making performance differed between the studies, though. Importantly, there was a negative influence of the number of players on decision-making quality in Studies 2 and 3, even though the authors tried to add players clearly farther away from the offside line than the relevant pair of players. This points to a crowding effect as a potential explanation for why decision-making quality decreases with an increasing number of players.

Measuring Early Problem-Solving in Young Children with Motor Delays: A Validation Study.

AIM: There is a lack of evidence-based tools for measuring problem-solving in young children with motor delays. The purpose of this study was to evaluate the construct validity and responsiveness of the Assessment of Problem-Solving in Play. METHODS: 125 young children (10.72, SD 2.62 months) with mild, moderate, and severe motor delays were assessed with the Bayley Scales of Infant and Toddler Development, Third Edition Cognitive Scale and the Assessment of Problem-Solving in Play up to 4 times over 12 months. The baseline and change over time assessment scores were compared. RESULTS: The Assessment of Problem-Solving in Play was strongly, positively correlated with the Bayley Scales of Infant and Toddler Development, Third Edition Cognitive Scale raw scores at baseline (r=.83, p<.001) and for changes in scores across time (r=.64, p<.001). On average, participants demonstrated positive change in problem-solving scores across time. Participants with severe motor delay scored lower at baseline and changed less as compared to other participants. CONCLUSIONS: Results provide evidence for the construct validity and responsiveness of the Assessment of Problem-Solving in Play scores in quantifying problem-solving in young children with motor delays 7-27 months of age.

Could Neurotracker be used as a clinical marker of recovery following pediatric mild traumatic brain injury? An exploratory study.

PRIMARY OBJECTIVE: This study aimed to explore the potential for the Neurotracker, a perceptual-cognitive, multiple-object tracking test, and train paradigm, as a marker of functional recovery after mild traumatic brain injury (mTBI). It is hypothesized that Neurotracker could serve as a proxy for assessing cerebral functioning. RESEARCH DESIGN: A comparative, 6 time points, longitudinal study design was used to compare Neurotracker performance between children and adolescents who were clinically recovered from mTBI and healthy controls. METHODS AND PROCEDURES: Clinical measures were collected at the initial and final visits. Neurotracker trainings were performed at each of the 6 visits. Speed thresholds (Neurotracker performance) were recorded at each visit. MAIN OUTCOMES AND RESULTS: A two-way repeated measures ANOVA suggested no differences between the groups but a significant time effect was apparent. CONCLUSIONS: Clinically recovered children and adolescents exhibit similar training abilities to control subjects on this task. These results support further investigations using Neurotracker as a marker of recovery following mTBI.

The impact of self-generated and explicitly acquired contextual knowledge on anticipatory performance.

The present study aimed to investigate the impact of self-generated and explicitly acquired contextual knowledge of teammates' defensive qualities on anticipatory performance in a complex sensorimotor task. Twelve expert and twelve near-expert handball players were examined in a domain-specific defence task presented in an immersive virtual-reality environment. In two-thirds of the trials, 1:1 situations (i.e., teammate versus opponent) were presented in which the teammates next to the participant played a specific role. Whilst the weak teammate lost every situation, which required the participant to block a throw, the strong teammate won every situation, which required the participant to stay in his position. Since explicit knowledge of this pattern was only provided in a later phase of the experiment, participants would have to generate the respective knowledge themselves beforehand. To this end, the following variables were analysed: the detection of experimentally induced patterns, the correctness of the participants' motor responses and their positioning as a function of the respective teammate's defensive quality. Main results showed that experts are better able to utilize both self-generated as well as explicitly acquired knowledge regarding teammates' defensive qualities, whereas near-experts' performance was enhanced only by explicitly provided contextual knowledge.

Examining the roles of working memory and visual attention in multiple object tracking expertise.

When tracking multiple moving targets among visually similar distractors, human observers are capable of distributing attention over several spatial locations. It is unclear, however, whether capacity limitations or perceptual-cognitive abilities are responsible for the development of expertise in multiple object tracking. Across two experiments, we examined the role of working memory and visual attention in tracking expertise. In Experiment 1, individuals who regularly engaged in object tracking sports (soccer and rugby) displayed improved tracking performance, relative to non-tracking sports (swimming, rowing, running) (p = 0.02, ηp2 = 0.163), but no differences in gaze strategy (ps > 0.31). In Experiment 2, participants trained on an adaptive object tracking task showed improved tracking performance (p = 0.005, d = 0.817), but no changes in gaze strategy (ps > 0.07). They did, however, show significant improvement in a working memory transfer task (p < 0.001, d = 0.970). These findings indicate that the development of tracking expertise is more closely linked to processing capacity limits than perceptual-cognitive strategies.

The role of viewing distance and viewing angle on referees' decision-making performance during the FIFA World Cup 2014.

The present study aims to reveal the effects of positioning on decision-making performance in top-level refereeing in association football. To this end, for all 64 matches of the FIFA World Cup 2014, potential foul-play situations were videometrically analysed in terms of the referee's position relative to the infringement. Contrary to earlier studies, viewing angles were analysed in addition to viewing distances and error rates were considered for not only falsely whistled but also falsely non-whistled events. Moreover, direct logistic regression analysis was applied to detect position-dependent differences. For the total of 1,527 potential foul play situations, an overall low error rate of 6.9% was found. The similar numbers of total whistle (n = 52) and non-whistle errors (n = 54) reflect referees' ability to balance both types of errors. Regarding the overall viewing-distance effect, referees were 2.58 times (95% CI 1.47-4.54) more likely to commit a whistle error at 10-15 m and 5.51 times (95% CI 1.35-22.47) more likely to commit a non-whistle error at 0-5 m, corresponding to the position ranges occurring with the highest (10-15 m: 30.3%) and lowest (0-5 m: 5.8%) frequencies. In contrast, no significant effects of viewing-angle on decision-making accuracy could be revealed.

Testing the functionality of peripheral vision in a mixed-methods football field study.

In team sports, peripheral vision might be useful to simultaneously monitor movements of opponents and teammates. Until now, however, little is known about the perceptual-cognitive processes underlying peripheral vision in a sporting task. Therefore, we used a mixed-methods approach with in-situ decision making (3 vs. 3 situations) and retrospective verbal reports to identify perceptual strategies used for optimal information pick-up in high- and low-skilled football players. Our results show that the use of peripheral vision by central defenders depends on the position of the ball and the position of the direct opponent. Players were shown to either use a pivot strategy, whereby they frequently look at the direct opponent if he is not in the possession of the ball in addition to making saccades to monitor other players, or they employ a more direct strategy, in which gaze is anchored on this location, avoiding saccades and monitoring the other players with peripheral vision. Based on our findings we make recommendations about how these gaze strategies can be further tested in future research and how sports practice can benefit from these results.

Quiet eye facilitates sensorimotor preprograming and online control of precision aiming in golf putting.

An occlusion protocol was used to elucidate the respective roles of preprograming and online control during the quiet eye period of golf putting. Twenty-one novice golfers completed golf putts to 6-ft and 11-ft targets under full vision or with vision occluded on initiation of the backswing. Radial error (RE) was higher, and quiet eye was longer, when putting to the 11-ft versus 6-ft target, and in the occluded versus full vision condition. Quiet eye durations, as well as preprograming, online and dwell durations, were longer in low-RE compared to high-RE trials. The preprograming component of quiet eye was significantly longer in the occluded vision condition, whereas the online and dwell components were significantly longer in the full vision condition. These findings demonstrate an increase in preprograming when vision is occluded. However, this was not sufficient to overcome the need for online visual control during the quiet eye period. These findings suggest the quiet eye period is composed of preprograming and online control elements; however, online visual control of action is critical to performance.

Exploring the interaction of physical exercise load and pattern recall performance in female handball players.

Studies examining experts' superiority within domain-specific structured pattern recall tasks have typically had athletes perform them at rest, which is far different from how they are executed in their sport. The aim of this study was to investigate whether performing these tasks under different physical exercise intensities influenced pattern recall results of experts, advanced and novices. In two experiments, 68 participants (experiment 1: n = 33; experiment 2: n = 35) were tested using a handball-specific pattern recall task both at rest and during physical exercise. Physical exercises of 60 % heart rate reserve (constant workload: experiment 1) and of 86.5-90 % HRmax (handball-specific interval load: experiment 2) were induced. Results of both experiments revealed significant group differences with experts recalling patterns more accurately than novices but no significant within-subject differences for the two conditions and no interaction between both factors. Our findings replicate prior research concerning perceptual-cognitive expertise in structured specific pattern recall tasks. However, the lack of intergroup differences between the two conditions or interactions was surprising, suggesting sport-specific pattern recall skill is robust to changes in exercise stimuli. Future work is needed to further examine the impact of "physiological specificity" on perceptual-cognitive expertise.

Anxiety, anticipation and contextual information: A test of attentional control theory.

We tested the assumptions of Attentional Control Theory (ACT) by examining the impact of anxiety on anticipation using a dynamic, time-constrained task. Moreover, we examined the involvement of high- and low-level cognitive processes in anticipation and how their importance may interact with anxiety. Skilled and less-skilled tennis players anticipated the shots of opponents under low- and high-anxiety conditions. Participants viewed three types of video stimuli, each depicting different levels of contextual information. Performance effectiveness (response accuracy) and processing efficiency (response accuracy divided by corresponding mental effort) were measured. Skilled players recorded higher levels of response accuracy and processing efficiency compared to less-skilled counterparts. Processing efficiency significantly decreased under high- compared to low-anxiety conditions. No difference in response accuracy was observed. When reviewing directional errors, anxiety was most detrimental to performance in the condition conveying only contextual information, suggesting that anxiety may have a greater impact on high-level (top-down) cognitive processes, potentially due to a shift in attentional control. Our findings provide partial support for ACT; anxiety elicited greater decrements in processing efficiency than performance effectiveness, possibly due to predominance of the stimulus-driven attentional system.

The effects of physical exertion on decision-making performance of Australian football umpires.

Decision-making is a key component of an umpire's in-game performance, with each decision potentially having a direct impact on the result of the game. Additionally, umpires have to be physically fit to ensure they keep up with the gameplay. While research has identified the decision-making demands and running demands of umpires separately, few have explored the relationship between them. The aim of this investigation was to examine the relationship between physical exertion and decision-making performance of Australian football umpires at the sub-elite and junior levels. A total of 18 Australian football umpires (sub-elite, n = 10; junior n = 8) performed 10 × 300 m runs, with each repetition immediately followed by a video-based decision-making test, then 1 min of recovery. A Mann-Whitney U assessment indicated a significant difference between the sub-elite and junior level umpires for decision-making accuracy (U = 13.00, z = -2.43, P = 0.016, r = -0.5). However, there was no significant difference in response time (U = 28.00, z = -1.07, P = 0.315, r = -0.25). The sub-elite umpires completed the running efforts in significantly less time than the junior umpires (P < 0.05). Further, there was no significant correlation between decision-making performance and running times for either skill level (P > 0.05). This suggests decision-making performance may not be affected by physical exertion. Therefore, it may be suggested coaches of football umpires allocate more time to the decision-making development of their umpires instead of focusing largely on the physical fitness side, as is currently the trend.