Is Anticipation Skill Learning Bayesian?

Purpose: The aims of this study were to examine the learning of anticipation skill in the presence of kinematic and outcome probabilities information, and to see if this learning exhibited characteristics of Bayesian integration. Method: Participants with no competitive tennis playing experience watched tennis player stimuli playing forehand tennis shots and were tasked with predicted shot outcomes. Accuracy, response times and perceived task effort were recorded, pre, post and during four acquisition blocks where outcome feedback was provided. In both Experiment 1 and 2, kinematic information about shot direction was either present in the training group stimuli or absent. In Experiment 1, left/right shot probability information remained equi-probable for both groups. In Experiment 2, both groups also trained with a bias in the shot outcome probability toward one shot direction on 80% of the trials across acquisition blocks (and were not told about this manipulation). Results: Pre-to-post anticipation performance improved in the presence of kinematic (EXP 1) or both information sources (EXP 2). Pre-to-post improvements in the presence of shot outcome probability information were congruent with the bias in the shot direction trained (EXP 2). Superior anticipation performance was found when both information sources were present. The presence of kinematic information resulted in increased perceived effort during early training (EXP 1 & 2). Bayesian odds ratios indicated that shot direction probabilities and kinematic information were integrated during anticipation skill learning. Conclusion: Learning with shot direction probabilities and kinematic information shows characteristics of Bayesian integration.

Skill and experience impact neural activity during global and local biological motion processing

During biological motion perception, individuals with perceptual experience learn to use more global processing, simultaneously extracting information from multiple body segments. Less experienced observers may use more local processing of individual body segments. The parietal lobe (e.g., alpha and beta power) has been shown to be critical to global and local static stimulus perception. Therefore, in this paper, we examined how skill impacts motion processing by assessing behavioral and neural responses to degrading global or local motion information for soccer penalty kicks. Skilled (N = 21) and less skilled (N = 19) soccer players anticipated temporally occluded videos of penalty kicks under normal, blurred (degraded local information), or spatially occluded (hips-only; degraded global information) viewing conditions. EEG was used to measure parietal alpha and beta power. Skilled players outperformed less skilled players, albeit both skill groups were less accurate in the blurred and hips-only conditions. Skilled performers showed significant decreases in bilateral parietal beta power in the hips-only condition, suggesting a greater reliance on global motion information under normal viewing conditions. Additionally, the hips-only condition elicited significantly greater beta relative to alpha power (beta - alpha), lower beta power, and lower alpha power than the control condition for both skill groups, suggesting spatial occlusion elicited a shift towards more local processing. Our novel findings demonstrate that skill and experience impact how motion is processed.

Skilled Performers Show Right Parietal Lateralization during Anticipation of Volleyball Attacks

Global and local biological motion processing are likely influenced by an observer's perceptual experience. Skilled athletes anticipating an opponent's movements use globally distributed motion information, while less skilled athletes focus on single kinematic cues. Published reports have demonstrated that attention can be primed globally or locally before perceptual tasks; such an intervention could highlight motion processing mechanisms used by skilled and less skilled observers. In this study, we examined skill differences in biological motion processing using attentional priming. Skilled (N = 16) and less skilled (N = 16) players anticipated temporally occluded videos of volleyball attacks after being primed using a Navon matching task while parietal EEG was measured. Skilled players were more accurate than less skilled players across priming conditions. Global priming improved performance in both skill groups. Skilled players showed significantly reduced alpha and beta power in the right compared to left parietal region, but brain activity was not affected by the priming interventions. Our findings highlight the importance of right parietal dominance for skilled performers, which may be functional for inhibiting left hemispheric local processing or enhancing visual spatial attention for dynamic visual scenes. Further work is needed to systematically determine the function of this pattern of brain activity during skilled anticipation.

Perceiving the inertial properties of actions in anticipation skill

Inertial properties of throwing or striking actions constrain action outcomes, but their role in anticipation skill has not been investigated yet. Therefore, the aim of this study was to systematically investigate the effect of inertial constraints on anticipation skill. Fifteen semi-professional and fifteen novice soccer players were tasked with determining the kick direction of penalty kicks occluded at 160 ms, 80 ms before ball-foot contact, at ball-foot contact, or 80 ms after ball-foot contact. The inertial constraints were manipulated by loading the kicking leg with a 2.25 kg weight around the shank of the kicking leg and were compared with unloaded kicks. Anticipation accuracy of kick direction, response time, and decision confidence were recorded. It was found that loaded kick directions were anticipated more accurately, faster, and at earlier occlusion periods than unloaded kicks. The higher accuracy for the loaded kicks was found in the earlier occlusion conditions in experts compared to novices, as were the positive relationships between accuracy and confidence. It was concluded that the perception of the inertial constraints of the kicking action allowed for earlier anticipation of kick direction. It is proposed that accurate perception of the biomechanical property radius of gyrations in the body segments linking proximal to distal towards the kicking foot may provide this information.

The effects of injury, contextual match factors and training load upon psychological wellbeing in English Premier League soccer players via season-long tracking

The study aimed to track psychological wellbeing (PWB) across two consecutive soccer seasons examining the effects of injury, illness, training load (TL) and contextual match factors (playing status, match selection and individual win rate). Furthermore, examine PWB prior to injury or illness event. Thirty-two English Premier League (EPL) soccer players completed the "Warwick-Edinburgh Mental Wellbeing Scale" every two weeks. No differences were found for group averaged PWB across the seasons (52.2 ± 0.3 vs. 51.8 ± 1.1) (p > 0.05). Previous 7-day TL measured using GPS (session duration, total distance, explosive distance, low-intensity distance, high-speed distance (HSD) and sprint distance (SD)) were not related to current PWB (p > 0.05). Yet, previous 14-day HSD (r (385) = -0.095) and 21-day SD (r (385) = 0.100) were related to current PWB (p < 0.05). Only 100% (vs. 0%) win rate in the previous 14-days to the questionnaire revealed a higher current PWB score (52.7 ± 4.7 vs. 50.9 ± 5.6 (p < 0.05)). PWB did not differ prior to an injury or illness event, when players were injured or had low contextual match factors at time of questionnaire or previous match, and the previous 7-days (p > 0.05). In conclusion, PWB fluctuations across the season are associated with prior TL and multiple negative results. But prior PWB was not linked to injury or illness events. Implications for prioritising interventions to improve PWB during periods of chronic high intensity TLs and losing streaks, monitoring PWB, and use in injury and illness prediction are discussed.HighlightsPsychological wellbeing responses, as measured by the "Warwick-Edinburgh Mental Wellbeing Scale" did not change significantly at a group level between the phases of the two seasons.Prior training load was associated with wellbeing scores, specifically previous 14-day high-speed distance and 21-day sprint distance.Psychological wellbeing scores were only affected by win/loss rate in the previous 14-days.These findings highlight the importance of timely interventions to improve wellbeing in periods of negative results, and the recommendation of longitudinally monitoring wellbeing.

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.

Spatial Separation and Working Memory Capacity Affect Selective Visual Attention in the Periphery

The current study aimed to examine the effects of spatial separation and working memory capacity on selective visual attention. We investigated differences in the ability to identify the two covertly attended stimuli that appeared either along one of the meridians (e.g., both along the horizontal) or along two of the meridians (e.g., one along the horizontal and one along the vertical) in the attention-window task. Two visual stimuli in the periphery could be perceived along wider extents of the attentional focus’ meridians (horizontal, vertical, and diagonal) when they were located along the same meridian (e.g., horizontal) compared to two different ones (e.g., horizontal and vertical). Subjects with high working memory capacity outperformed subjects with lower working memory capacity in both conditions and stimuli presented on two meridians were less accurately perceived. The findings support the proposal that individual differences in working memory capacity are important for selective spatial visual attention.

Physical activity on mental wellbeing in senior English Premier League soccer players during the COVID-19 pandemic and the lockdown

The COVID-19 pandemic and the subsequent lockdown created new stressors that could potentially attenuate mental wellbeing (MW) in athletes, who are already susceptible to poor MW. This study aims to describe fluctuations to MW during "lockdown" and subsequent "return to sport" protocols, in comparison to the normal "in-season" in professional soccer. Twenty-five English Premier League (EPL) soccer players completed the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS) every two weeks, during the 2019/2020 season, and every week during "lockdown" and "return to training" for 28 weeks. The duration of each physical activity (PA) session completed was recorded. No significant differences were found for MW between time points (In-season, lockdown, return to training and the restart) (51.5 ± 5.6 vs. 50.7 ± 4.8 vs. 50.8 ± 5.7 vs. 50.7 ± 5.6 (p > 0.05)) respectively. Individually, differences were identified; in-season weekly session duration (243 ± 38 min) was higher than during lockdown (180 ± 62 min) (p < 0.05). During lockdown, weekly MW scores were related to the previous 7-day number of sessions (r = 0.151) and active min (r = 0.142) (p < 0.05). Furthermore, participants that exercised >250 min in lockdown, had higher MW scores (52.46 ± 4.65) than <250 min (50.35 ± 6.55) (p < 0.05). MW responses to lockdown were best understood on an individual basis. Additionally, PA only had a measurable effect on MW when >250 min. Further, stressors imposed upon players during an EPL season, are potentially greater than those inflicted by the lockdown. Implications for monitoring MW in EPL soccer players and the potential inclusion of an in-season break are discussed.Highlights Mental Wellbeing Responses, as measured by the Warwick-Edinburgh Mental Wellbeing scale did not change significantly at a group level across the four phases of the season. However, on an individual level changes were evident.There was a decline in the trend of wellbeing scores during in-season, return to training and the restart, but an increase in wellbeing scores during lockdown.Physical Activity had a measurable effect on wellbeing, when physical activity was >250 min during lockdown.These findings highlight the need for individual monitoring of wellbeing and longitudinal monitoring in sport to identify decline in wellbeing and implement intervention. In addition, the prescription of physical activity >250 min per week during lockdown in trained athletes may promote positive mental health.

Coordination between motor and cognitive tasks in dual task gait

BACKGROUND

Dual Task (DT) paradigms are frequently used by researchers and clinicians to examine the integrity of motor processes in many movement disorders. However, the mechanism of this interaction is not fully understood. Therefore, the aim of this study was to examine the within-stride interactions between cognitive and motor processes during dual task gait (DT).

RESEARCH QUESTION

Do healthy young adults coordinate gait with secondary task processing? If so, is cognitive task processing capability associated with the coordination observed?

METHODS

Nineteen healthy young adults walked for two minutes on a motorized treadmill whilst counting backwards in sevens from three-digit numbers. The coordination of calculation verbalizations with gait parameters were assessed across six phases of the gait cycle. Mid verbalization time points (VER_Mid) were used as points of high cognitive processing of the dual task and compared with the end of the verbalizations (VER_End) as points of low cognitive processing.

RESULTS

VER_Mid and VER_End did not systematically occur in any phase of the gait cycle. However, 10/19 and 9/19 participants showed non-random distributions of verbalizations for VER_Mid and VER_End time points respectively (p < 0.01), indicating that these walkers coordinated gait with the cognitive task. Analysis of subgroups of Verbalization Coordinators and Non-Coordinators showed slower verbalization response durations (VRD) for VER_Mid Coordinators compared to VER_Mid Non-Coordinators, indicating that VER_Mid Coordinators found the cognitive tasks more demanding. No differences were found in VRD for VER_End Coordinators and VER_End Non-Coordinators.

SIGNIFICANCE

It was found that cognitive processing is coordinated with gait phases in some but not all healthy young adults during DT gait. When demands on cognitive processes are high, healthy young adults coordinate cognitive processing with phases of gait. Analysis of within-stride coordination may be of use for studying clinical conditions where gait and attentional cognition performance breaks down.

Processing visual information in elite junior soccer players: Effects of chronological age and training experience on visual perception, attention, and decision making

Processing information in peripheral vision is an important perceptual-cognitive skill in team sports. The relative contribution of various perceptual-cognitive skills to expertise in sports throughout adolescence has not been investigated in detail yet. The current study examined the effects of chronological age and training experience on perception, attention, and decision making in young soccer players. Sixty-five elite youth players were required to judge different game situations in a decision-making task involving both perceptual (object detection) and attentional (postural feature recognition) skills to perceive player configurations in the visual periphery. In general, performance decreased in the decision-making and feature-recognition tasks with increasing use of peripheral visual field, but not in the object-detection task. Superior performances were found for under 18-years-old players compared to under 16-years-old players especially in their attentional skills. Higher training experience affected decision-making and attentional performance. Overall, the findings provide insights and implications for training perceptual-cognitive skills in team sportsHighlights Elite youth soccer players' performance decreased in a soccer-specific decision-making and feature-recognition tasks with increasing use of peripheral visual field, but not in an object-detection task.Superior performances were found for under 18 years old players compared to under 16 years old players especially in their attentional skills.Both chronological age and training experience influenced the recognition of postural feature in peripheral vision, whereas player detection was unaffected.The ability to recognize postural features in peripheral vision is an important characteristic of decision making in sports and requires a mature visual system, sufficient attentional capacity, and may be developed through extended task-specific practice.

Visual and Auditory Information During Decision Making in Sport

In 2 experiments, the authors investigated the effects of bimodal integration in a sport-specific task. Beach volleyball players were required to make a tactical decision, responding either verbally or via a motor response, after being presented with visual, auditory, or both kinds of stimuli in a beach volleyball scenario. In Experiment 1, players made the correct decision in a game situation more often when visual and auditory information were congruent than in trials in which they experienced only one of the modalities or incongruent information. Decision-making accuracy was greater when motor, rather than verbal, responses were given. Experiment 2 replicated this congruence effect using different stimulus material and showed a decreasing effect of visual stimulation on decision making as a function of shorter visual stimulus durations. In conclusion, this study shows that bimodal integration of congruent visual and auditory information results in more accurate decision making in sport than unimodal information.

Dual-task prioritization during overground and treadmill walking in healthy adults

BACKGROUND

The dual-task effect on walking performance is different during treadmill and overground walking, though the cause of this difference is unknown. This study examined the effects of task prioritization on overground and treadmill dual-task walking.

METHOD

Twenty-two adults walked overground and on a treadmill under three dual-task conditions: prioritization of walking performance, prioritization of cognitive performance (serial subtraction in sevens), or no prioritization.

RESULTS

Compared to single-task walking, stride velocity was reduced and stride time variability was increased during dual-task overground walking. During treadmill walking, there was no dual-task effect on walking performance, but cognitive task performance was improved. Prioritization of the cognitive task reduced the dual-task effect on stride velocity during overground walking only, whilst prioritization of the walking task reduced cognitive task performance in both walking modalities.

SIGNIFICANCE

These results corroborate recent findings that the dual-task effects on treadmill walking are not equivalent to those on overground walking. Healthy adults appear to prioritize cognitive task performance during treadmill dual-task walking without detrimental effects to gait. During overground walking however, allocation of attention to the secondary task reduces gait performance. These results indicate that treadmill based dual-task paradigms should not be used to infer factors which influence the cognitive control of overground walking.

Immersive screens change attention width but not perception or decision-making performance in natural and basic tasks

In the last decades, a number of studies have examined people's perceptual and attentional capabilities using flat screen displays. The completion of studies using curved displays/screens has been neglected so far, despite their advantage of creating a more immersive and life-like experience. In two studies, we analysed possible performance differences between subjects' perceptual and attentional capabilities during a decision-making task whilst viewing life-size stimuli on large flat and curved immersive screens. In Study 1, participants performed an attention-demanding shape discrimination task. In Study 2, participants performed a more naturalistic football-specific discrimination task. Results of both studies revealed no differences in perception and decision making between screen conditions, but that attention can be directed across greater visual angles on immersive screens compared to flat screens. The findings suggest that attention can be directed across a larger visual angle on curved screens compared to flat screens probably because curved screens distort the image less than flat screens. This study has implications for the use of flat screens in studies that examine perceptual and attentional capabilities in the visual periphery.

Attention, Perception, and Action in a Simulated Decision-Making Task

Over the last decade, research on the visual focus of attention has become increasingly popular in psychological science. The focus of attention has been shown to be important in fast team-sport games. The authors developed a method that measures the extent of the attentional focus and perceptual capabilities during performance of a sport-specific task. The participants were required to judge different player configurations on their left and right sides with varying visual angles between the stimuli. In keeping with the notion that the focus of attention is smaller than the visual field, attentional performance was poorest at the wider viewing angles compared with perceptual performance. Moreover, the team-sport players were better able to enlarge their attentional focus and make correct decisions more frequently than individual athletes, particularly when a motor response was required. The findings provide a new perspective, dissociating the attentional and perceptual processes that affect decision making under various response modes.

Individualizing Acceleration in English Premier League Academy Soccer Players

Abbott, W, Brickley, G, Smeeton, NJ, and Mills, S. Individualizing acceleration in English Premier League academy soccer players. J Strength Cond Res 32(12): 3512-3519, 2018-Global thresholds are typically used to band acceleration dependent on intensity. However, global thresholds do not account for variation in individual capacities, failing to quantify true intensity of acceleration. Previous research has investigated discrepancies in high-speed distance produced using global and individual speed thresholds, not yet investigated for acceleration. The current aim was to investigate discrepancies between global and individual thresholds when quantifying acceleration tasks. Acceleration data were recorded for 31 professional soccer players, using 10-Hz global positioning systems devices. Distances traveled performing low-, moderate-, and high-intensity acceleration were calculated for athletes using global and individual thresholds. Global acceleration thresholds for low-, moderate-, and high-intensity acceleration were classified as 1-2, 2-3, and >3 m·s, respectively, with individual thresholds classified as 25-50%, 50-75%, and >75% of maximum acceleration, respectively. Athletes were grouped low (LO), medium (ME), or high (HI) maximum accelerative capacity, determined using 3 maximal 40-m linear sprints. Two-way mixed-design analyses of variance were used to analyze differences in acceleration distances produced between analysis methods and athlete groups. No significant differences were identified between analysis methods for LO. For ME, no significant differences were demonstrated for low intensity. Moderate- and high-intensity acceleration distances were significantly higher for global compared with individual analysis method (p < 0.01). For HI, significantly higher acceleration distances were produced for all acceleration intensities using global thresholds (p < 0.01). Significant differences identified between analysis methods suggest practitioners must apply caution when using global thresholds. Global thresholds do not account for individual capacities and may provide an inaccurate representation of relative intensity of acceleration tasks.

Color Perception and Attentional Load in Dynamic, Time-Constrained Environments

The capacity to perceive color in the peripheral field has attracted research interest for more than a decade. There is evidence that sensitivity to red-green color variations is lower than for yellow-blue in peripheral vision. Whether, and to what extent, color vision affects the visual focus of attention, which is normally much smaller than the visual field, has not yet been examined. We used a sport-specific decision-making task to assess whether the color of the jersey worn by players appearing in the periphery influences decision making by affecting the attentional and perceptual capabilities. Pairs of players wearing chromatic (blue, yellow, red, and green) and achromatic (black, white) colored jerseys were briefly presented across a range of visual angles on a 6 m concave immersive screen. Participants were required to decide to whom to pass and recall relevant information. Findings indicate that color perception changes vary with increasing visual angle, but that the focus of attention is too small to be influenced by jersey color sensitivity. Decision-making performance decreases with increasing visual angle, but is not influenced by color. The implications for decision-making processes in sport and other professional domains are discussed.

Disguise and Deception of Action Outcomes Through Sports Garment Design Impair Anticipation Judgments

The ability to disguise and deceive action outcomes was examined by manipulating sports garments. In Experiment 1, those with higher and lower skill levels in anticipation predicted the throw direction of an opponent who wore a garment designed to disguise kinetic-chain information. Higher skill anticipators were more adversely affected by the disguise garment than the lower skill anticipators, demonstrating that disguise removed the anticipation advantage. In Experiment 2, using the same occlusion methodology, the effect of deception was examined using 2 garments designed to create visual illusions of motion across the proximal-to-distal sequence of the thrower's action and compared with a white-garment control. Performances for the deceptive garments were reduced relative to the control garment at the earliest occlusion points for the rightmost targets, but this effect was reversed for the leftmost targets at the earliest occlusion point, suggesting that the visual illusion garments were deceiving participants about motion information from the proximal-to-distal sequence of the action.

Walking modality, but not task difficulty, influences the control of dual-task walking

During dual-task gait, changes in the stride-to-stride variability of stride time (STV) are suggested to represent the allocation of cognitive control to walking [1]. However, contrasting effects have been reported for overground and treadmill walking, which may be due to differences in the relative difficulty of the dual task. Here we compared the effect of overground and treadmill dual-task walking on STV in 18 healthy adults. Participants walked overground and on a treadmill for 120s during single-task (walking only) and dual-task (walking whilst performing serial subtractions in sevens) conditions. Dual-task effects on STV, cognitive task (serial subtraction) performance and perceived task difficulty were compared between walking modalities. STV was increased during overground dual-task walking, but was unchanged during treadmill dual-task walking. There were no differences in cognitive task performance or perceived task difficulty. These results show that gait is controlled differently during overground and treadmill dual-task walking. However, these differences are not solely due to differences in task difficulty, and may instead represent modality dependent control strategies.

Expertise differences in anticipatory judgements during a temporally and spatially occluded task

There is contradictory evidence surrounding the role of critical cues in the successful anticipation of penalty kicks in soccer. In the current study, skilled and less-skilled soccer goalkeepers were required to anticipate when viewing penalty kicks that were both spatially (full body; hip region) and temporally (–160 ms, –80 ms before, foot–ball contact) occluded. The skilled group outperformed the less-skilled group in all conditions. Participants performed better in the full body condition when compared to hip region condition. Performance in the hip only condition was significantly better than chance for the skilled group across all occlusion conditions. However, the less-skilled group were no better than chance in the hip condition for the early occlusion points when predicting direction and height. Later temporal occlusion conditions were associated with increased performance both in the correct response and correct direction analyses, but not for correct height. These data suggest that postural information solely from the hip region may be used by skilled goalkeepers to make accurate predictions of penalty kick direction, however, information from other sources are needed in order to make predictions of height. Findings demonstrate how the importance of anticipation cues evolve over time, which has implications for the design of training programs to enhance perceptual-cognitive skill.

Short-term heat acclimation prior to a multi-day desert ultra-marathon improves physiological and psychological responses without compromising immune status

Multistage, ultra-endurance events in hot, humid conditions necessitate thermal adaptation, often achieved through short term heat acclimation (STHA), to improve performance by reducing thermoregulatory strain and perceptions of heat stress. This study investigated the physiological, perceptual and immunological responses to STHA prior to the Marathon des Sables. Eight athletes (age 42 ± 4 years and body mass 81.9 ± 15.0 kg) completed 4 days of controlled hyperthermia STHA (60 min·day^‒1, 45°C and 30% relative humidity). Pre, during and post sessions, physiological and perceptual measures were recorded. Immunological measures were recorded pre-post sessions 1 and 4. STHA improved thermal comfort (P = 0.02), sensation (P = 0.03) and perceived exertion (P = 0.04). A dissociated relationship between perceptual fatigue and T_re was evident after STHA, with reductions in perceived Physical (P = 0.04) and General (P = 0.04) fatigue. Exercising T_re and HR did not change (P > 0.05) however, sweat rate increased 14% (P = 0.02). No changes were found in white blood cell counts or content (P > 0.05). Four days of STHA facilitates effective perceptual adaptations, without compromising immune status prior to an ultra-endurance race in heat stress. A greater physiological strain is required to confer optimal physiological adaptations.

Exercise Performance and Corticospinal Excitability during Action Observation

Purpose: Observation of a model performing fast exercise improves simultaneous exercise performance; however, the precise mechanism underpinning this effect is unknown. The aim of the present study was to investigate whether the speed of the observed exercise influenced both upper body exercise performance and the activation of a cortical action observation network (AON).

Method: In Experiment 1, 10 participants completed a 5 km time trial on an arm-crank ergometer whilst observing a blank screen (no-video) and a model performing exercise at both a typical (i.e., individual mean cadence during baseline time trial) and 15% faster than typical speed. In Experiment 2, 11 participants performed arm crank exercise whilst observing exercise at typical speed, 15% slower and 15% faster than typical speed. In Experiment 3, 11 participants observed the typical, slow and fast exercise, and a no-video, whilst corticospinal excitability was assessed using transcranial magnetic stimulation.

Results: In Experiment 1, performance time decreased and mean power increased, during observation of the fast exercise compared to the no-video condition. In Experiment 2, cadence and power increased during observation of the fast exercise compared to the typical speed exercise but there was no effect of observation of slow exercise on exercise behavior. In Experiment 3, observation of exercise increased corticospinal excitability; however, there was no difference between the exercise speeds.

Conclusion: Observation of fast exercise improves simultaneous upper-body exercise performance. However, because there was no effect of exercise speed on corticospinal excitability, these results suggest that these improvements are not solely due to changes in the activity of the AON.

When less is more: reduced usefulness training for the learning of anticipation skill in tennis

Participants in this study practiced with feedback to anticipate the left-right direction of forehand tennis shots played by stick-figure players. A technique based on principal component analysis was used to remove dynamical differences that are associated with shots to different directions. Different body regions of the stick-figure players were neutralized with this procedure in the pretests and posttests, and in the practice phases. Experiment 1 showed that training is effective if during practice information is consistently present in the whole body of the player, but not if the information is neutralized in the whole body in half of the practice trials. Experiment 2 showed that training is effective if the variance associated with the direction of the shots is consistently present in one body region but neutralized in others, and that transfer occurs from practice with information in one body region to performance in conditions with information preserved only in other regions. Experiment 3 showed that occlusion has a much larger detrimental effect on learning than the applied neutralization technique, and that transfer between body regions occurs also with occlusion. Discussed are theoretical implications for understanding how biological motion is perceived and possible applications in a type of training referred to as reduced usefulness training.

The role of movement exaggeration in the anticipation of deceptive soccer penalty kicks

Human movement containing deception about the true outcome is thought to be perceived differently compared to the non-deceptive version. Exaggeration in the movement is thought to change the perceiver's mode of functioning from an invariant to a cue-based mode. We tested these ideas by examining anticipation in skilled and less skilled soccer players while they viewed temporally occluded (-240 ms, -160 ms, -80 ms, 0 ms, +80 ms) deceptive, non-deceptive, and non-deceptive-exaggerated penalty kicks. Kinematic analyses were used to ascertain that the kicking actions differed across conditions. The accuracy of judging the direction of an opponent's kick as well as response confidence were recorded. Players were over confident when anticipating deceptive penalty kicks compared to non-deceptive kicks, suggesting a cue-based mode was used. Furthermore, there was a significant relationship between less skilled players' confidence ratings and their accuracy 80 ms before ball-foot contact in the deceptive and non-deceptive-exaggerated conditions, but not the non-deceptive condition. Because both deceptive and non-deceptive-exaggerated kicks contained exaggeration, results suggest exaggerated movements in the kickers' action at 80 ms before ball-foot contact explains why a cue-based mode prevails when anticipating deceptive kicks at this time point.

Absence of neuropsychological impairment in hyperammonaemia in healthy young adults; possible synergism in development of hepatic encephalopathy (HE) symptoms?

The aetiology of minimal hepatic encephalopathy (mHE) remains unclear. It is generally accepted that hyperammonaemia plays a major role, however there are a multitude of metabolic perturbations present. To determine the contribution of hyperammonaemia to mHE symptom development, ten healthy males (Age:25 ± 5 yrs, BM:76.3 ± 7.1 kg, Height:178.6 ± 4.5 cm, mean ± SD) received two 4 h intravenous infusions of either a 2% ammonium chloride solution (AMM) or a placebo (PLA;0.9% sodium chloride) using a double blind cross-over design. Sensations of fatigue were measured at baseline, 2 and 4 h using the Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF) questionnaire. Learning & memory, motor control and cognition were assessed using Rey's Auditory Verbal Learning Test (AVL), Continuous Compensatory Tracking (COMPTRACK) Task and Inhibitory Control Test (ICT) respectively. Arterialised venous blood samples were collected every hour, and analysed for ammonia concentration. There was a significantly higher plasma ammonia concentration in the AMM trial than the PLA trial at every time point during the infusion, peaking at 2 h (57 ± 4 μmol/L PLA, 225 ± 14 μmol/L AMM; p < 0.05). At 2 h there were significantly higher sensations of general fatigue (Z = -2.527, p = 0.008, 2 tailed) and physical fatigue (Z = -2.156, p = 0.027, 2 tailed), and lower sensations of vigour (Z = -2.456, p = 0.012, 2 tailed) for the AMM trial. There were no significant effects on the performance of the psychological tasks. These results demonstrate that hyperammonaemia in the absence of other complications induces significant sensations of fatigue but does not cause the typically observed performance impairment in individuals with mHE. Supporting the hypothesis for synergism between ammonia and other co-factors in mHE.

Ammonia metabolism, the brain and fatigue; revisiting the link

This review addresses the ammonia fatigue theory in light of new evidence from exercise and disease studies and aims to provide a view of the role of ammonia during exercise. Hyperammonemia is a condition common to pathological liver disorders and intense or exhausting exercise. In pathology, hyperammonemia is linked to impairment of normal brain function and the onset of the neurological condition, hepatic encephalopathy. Elevated blood ammonia concentrations arise due to a diminished capacity for removal via the liver and lead to increased exposure of organs, such as the brain, to the toxic effects of ammonia. High levels of brain ammonia can lead to deleterious alterations in astrocyte morphology, cerebral energy metabolism and neurotransmission, which may in turn impact on the functioning of important signalling pathways within the neuron. Such changes are believed to contribute to the disturbances in neuropsychological function, in particular the learning, memory, and motor control deficits observed in animal models of liver disease and also patients with cirrhosis. Hyperammonemia in exercise occurs as a result of an increased production by contracting muscle, through adenosine monophosphate (AMP) deamination (the purine nucleotide cycle) and branched chain amino acid (BCAA) deamination prior to oxidation. Plasma concentrations of ammonia during exercise often achieve or exceed those measured in liver disease patients, resulting in increased cerebral uptake. In this article we propose that exercise-induced hyperammonemia may lead to concomitant disturbances in brain function, potentially through similar mechanisms underpinning pathology, which may impact on performance as fatigue or reduced function, especially during extreme exercise.

The Relative Effectiveness of Various Instructional Approaches in Developing Anticipation Skill

The relative effectiveness of explicit instruction, guided discovery, and discovery learning techniques in enhancing anticipation skill in young, intermediate-level tennis players was examined. Performance was assessed pre- and postintervention, during acquisition, and under transfer conditions designed to elicit anxiety through the use of laboratory and on-court measures. The 3 intervention groups improved from pre- to posttest compared with a control group (n = 8), highlighting the benefits of perceptual-cognitive training. Participants in the explicit (n = 8) and guided discovery (n = 10) groups improved their performance during acquisition at a faster rate than did the discovery learning (n = 7) group. However, the explicit group showed a significant decrement in performance when tested under anxiety provoking conditions compared with the guided discovery and discovery learning groups. Although training facilitated anticipation skill, irrespective of the type of instruction used in this experiment, guided discovery methods are recommended for expediency in learning and resilience under pressure.

Do pattern recognition skills transfer across sports? A preliminary analysis

The ability to recognize patterns of play is fundamental to performance in team sports. While typically assumed to be domain-specific, pattern recognition skills may transfer from one sport to another if similarities exist in the perceptual features and their relations and/or the strategies used to encode and retrieve relevant information. A transfer paradigm was employed to compare skilled and less skilled soccer, field hockey and volleyball players' pattern recognition skills. Participants viewed structured and unstructured action sequences from each sport, half of which were randomly represented with clips not previously seen. The task was to identify previously viewed action sequences quickly and accurately. Transfer of pattern recognition skill was dependent on the participant's skill, sport practised, nature of the task and degree of structure. The skilled soccer and hockey players were quicker than the skilled volleyball players at recognizing structured soccer and hockey action sequences. Performance differences were not observed on the structured volleyball trials between the skilled soccer, field hockey and volleyball players. The skilled field hockey and soccer players were able to transfer perceptual information or strategies between their respective sports. The less skilled participants' results were less clear. Implications for domain-specific expertise, transfer and diversity across domains are discussed.

Anticipation skill in a real-world task: measurement, training, and transfer in tennis

Anticipation skill in tennis was examined using realistic film simulations, movement-based response measures, and a portable eye movement recording system. Skilled players were faster than their less skilled counterparts in anticipating the direction of opponents' tennis strokes, with this superior performance being based, at least in part, on more effective visual search behaviors. The processes mediating superior performance were then modeled in groups of recreational tennis players using video simulation, instruction, and feedback. Players who received perceptual training improved their performance on laboratory- and field-based tests of anticipation when compared with matched placebo and control groups that did not receive any instruction regarding expert performance strategies. The approach used may have practical utility in a variety of performance contexts.

Anticipation skill in a real-world task: measurement, training, and transfer in tennis

Anticipation skill in tennis was examined using realistic film simulations, movement-based response measures, and a portable eye movement recording system. Skilled players were faster than their less skilled counterparts in anticipating the direction of opponents' tennis strokes, with this superior performance being based, at least in part, on more effective visual search behaviors. The processes mediating superior performance were then modeled in groups of recreational tennis players using video simulation, instruction, and feedback. Players who received perceptual training improved their performance on laboratory- and field-based tests of anticipation when compared with matched placebo and control groups that did not receive any instruction regarding expert performance strategies. The approach used may have practical utility in a variety of performance contexts.