Matt Dicks

A test of the catecholamines hypothesis for an acute exercise–cognition interaction

The purpose of the study was to examine the usage of norepinephrine (NE) and dopamine (DA) in the brain when exercising while simultaneously undertaking cognitive tests. Plasma concentrations of the NE metabolite 3-methoxy 4-hydroxyphenylglycol (MHPG) and the DA metabolite homovanillic acid (HVA) showed a linear increase from rest to exercising at 40% and 80% maximum power output (W.max) while simultaneously undertaking cognitive tasks (random number generation (RNG) and response time). Delta plasma concentrations of MHPG and HVA at each exercise intensity while undertaking cognitive tasks and while exercising without cognitive tasks did not differ. Taking blood samples at 0, 1, 3, and 5 min following cessation of exercise did not affect results. Regression correlations showed that delta MHPG and HVA plasma concentrations at the 1 and 3 min sampling times were strong predictors of delta RNG, response time and movement time. Reaction time at 80% W.max significantly increased, while movement time at 80% W.max significantly decreased. It was concluded that these results provide no support for a direct effect of increased catecholamines concentrations on cognitive performance during exercise. The regression data suggest that there is some relationship between exercise, catecholamines concentrations and cognition.

Influence of competition on performance and pacing during cycling exercise

PURPOSE The studys purpose was to examine the influence of head-to-head (HH) competition on performance, pacing strategy, and bioenergetics during a 2000-m cycling task. METHODS Fourteen participants completed three 2000-m familiarization time trials (TTs) on a Velotron cycle ergometer, before completing an additional TT and a 2000-m simulated HH competition in a counterbalanced order. During the trials, a computer-generated image of the participants completing the 2000-m course was projected onto a screen positioned in front of the participants. Although participants believed they were competing against another individual during the HH competition, they were in fact competing against their best familiarization performance (FAM), replayed on the screen by the Velotron software. RESULTS Performance was significantly faster in HH than in FAM or TT (184.6 ± 6.2, 187.7 ± 8.2, and 188.3 ± 9.5 s, respectively). Pacing profile in HH initially matched the FAM performance but was better maintained from 1000 m until the end of exercise. The higher power output during the latter part of the test was achieved by a greater anaerobic energy contribution, whereas the aerobic energy yield remained unchanged. CONCLUSIONS HH competition encourages participants to increase their performance. This occurs primarily via an increased anaerobic energy yield, which seems to be centrally mediated, and is consistent with the concept of a physiologic reserve.

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

Abstract 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.

Statistical modelling of gaze behaviour as categorical time series: what you should watch to save soccer penalties

Previous research on gaze behaviour in sport has typically reported summary fixation statistics thereby largely ignoring the temporal sequencing of gaze. In the present study on penalty kicking in soccer, our aim was to apply a Markov chain modelling method to eye movement data obtained from goalkeepers. Building on the discrete analysis of gaze employed by Dicks et al. (Atten Percept Psychophys 72(3):706–720, 2010b), we wanted to statistically model the relative probabilities of the goalkeeper’s gaze being directed to different locations throughout the penalty taker’s approach (Dicks et al. in Atten Percept Psychophys 72(3):706–720, 2010b). Examination of gaze behaviours under in situ and video-simulation task constraints reveals differences in information pickup for perception and action (Attention, Perception and Psychophysics 72(3), 706–720). The probabilities of fixating anatomical locations of the penalty taker were high under simulated movement response conditions. In contrast, when actually required to intercept kicks, the goalkeepers initially favoured watching the penalty taker’s head but then rapidly shifted focus directly to the ball for approximately the final second prior to foot-ball contact. The increased spatio-temporal demands of in situ interceptive actions over laboratory-based simulated actions lead to different visual search strategies being used. When eye movement data are modelled as time series, it is possible to discern subtle but important behavioural characteristics that are less apparent with discrete summary statistics alone.

Deception, Individual Differences and Penalty Kicks: Implications for Goalkeeping in Association Football:

The purpose of the current article is to review findings from the visual anticipation literature with a particular focus on penalty kick goalkeeping in Association football. We give a brief introduction to the area of research before providing reviews of two recent studies. First, we focus on the applied implications of a study that examined the effect of deception and non-deception penalty kick strategies on goalkeeping performance. Second, we consider further limiting factors on the accuracy of goalkeeper visual anticipation through examination of the relationship between goalkeeper action capabilities and the timing and accuracy of goalkeeper responses. Finally, the implications of the results are considered with recommendations for coaching practices aimed at improving visual anticipation skills.

Neurophysiological Studies May Provide a Misleading Picture of How Perceptual-Motor Interactions are Coordinated

Neurophysiological measurement techniques like fMRI and TMS are increasingly being used to examine the perceptual-motor processes underpinning the ability to anticipate the actions of others. Crucially, these techniques invariably restrict the experimental task that can be used and consequently limit the degree to which the findings can be generalised. These limitations are discussed based on a recent paper by Tomeo et al. (2012) who sought to examine responses to fooling actions by using TMS on participants who passively observed spliced video clips where bodily information was, and was not, linked to the action outcome. We outline two particular concerns with this approach. First, spliced video clips that show physically impossible actions are unlikely to simulate a “fooling” action. Second, it is difficult to make meaningful inferences about perceptual-motor expertise from experiments where participants cannot move. Taken together, we argue that wider generalisations based on these findings may provide a misunderstanding of the phenomenon such a study is designed to explore.

Emergence of Contact Injuries in Invasion Team Sports: An Ecological Dynamics Rationale

The incidence of contact injuries in team sports is considerable, and injury mechanisms need to be comprehensively understood to facilitate the adoption of preventive measures. In Association Football, evidence shows that the highest prevalence of contact injuries emerges in one-on-one interactions. However, previous studies have tended to operationally report injury mechanisms in isolation, failing to provide a theoretical rationale to explain how injuries might emerge from interactions between opposing players. In this position paper, we propose an ecological dynamics framework to enhance current understanding of behavioural processes leading to contact injuries in team sports. Based on previous research highlighting the dynamics of performer–environment interactions, contact injuries are proposed to emerge from symmetry-breaking processes during on-field interpersonal interactions among competing players and the ball. Central to this approach is consideration of candidate control parameters that may provide insights on the information sources used by players to reduce risk of contact injuries during performance. Clinically, an ecological dynamics analysis could allow sport practitioners to design training sessions based on selected parameter threshold values as primary and/or secondary preventing measures during training and rehabilitation sessions.

“White men can't jump.” but can they throw?: social perception in European basketball

In the present article, we investigate the influence of sociocultural stereotypes on the impression formation of basketball players and coaches. In Experiment 1 (n = 32), participants were shown a picture of a black or white basketball player prior to observation of a point‐light video of a player executing a basketball free throw. The participant was informed that the player depicted in the picture was executing the free throw. Results indicated that ethnicity of the target player significantly influenced participant evaluations, demonstrating specific stereotypes about black and white basketball players when evaluating performance. In Experiment 2 (n = 30), results derived from the Implicit Association Test indicated that black players are implicitly associated with athletic player attributes. The results are in line with social schema theory and demonstrate that – similar to findings that have been reported in the United States – a subpopulation of German basketball players and coaches hold specific stereotypes about the abilities of black and white basketball athletes. These stereotypes bias impression formation when coaches and players make assessments of basketball performance.

Put Your Money Where Your Mouth Is: Verbal Self-Reported Tactical Skills Versus On-Line Tactical Performance in Soccer

The main goal of the study was to examine whether a relationship existed between self-reported and in situ tactical decision-making in the form of actions for small-sided soccer games, namely 4-vs.-4 and 8-vs.-8 games. Sixteen skilled male soccer players participated and completed the Tactical Skills Inventory for Sport Questionnaire (TACSIS). In addition, their decision-making performance was assessed for two 4-vs.-4 and one 8-vs.-8 small-sided soccer games. Video-analysis of the small-sided games was conducted to determine the successful and unsuccessful actions of each player. A performance ratio was calculated for each player based on the small-sided game analyses, which reflected the number of successful decisions made by players; that is, the number of successful ball actions divided by total ball actions. Correlation analysis revealed no significant relationship between the procedural knowledge TACSIS questionnaire scores and performance in the small-sided games. The findings are discussed within the theoretical framework of the two-visual system model and the repercussion for the use of questionnaires for talent identification.

The effect of altered ball approach on kick kinematics and shot accuracy: a soccer case study

Soccer instep kick kinematics has been examined in the literature through 2D analysis and more recently 3D analysis (Levanon and Dapena, 1998: Medicine and Science in Sports and Exercise, 30, 917–927). The importance of ball approach prior to kick execution has been recognised in other sports such as rugby (Jackson and Baker, 2001: The Sport Psychologist, 15, 48–65). However, there is limited research on the relationship between ball approach, shot accuracy and kick kinematics in soccer. The objective of this case study was to establish the effect of altering the ball approach, on kick kinematics and shot accuracy, when performing instep penalty kicks.Annual Conference of the British Association of Sport and Exercise Sciences Liverpool, 7th – 9th September 2004 PART I. BIOMECHANICS 20. Parameter determination for a torque-driven model of springboard diving takeoff P.W. Kong, M.R. Yeadon and M.A. King School of Sport and Exercise Sciences, Loughborough University, Ashby Road, Loughborough, LE11 3TU In order to develop a planar computer simulation model of a springboard and a 8-segment diver suitable for investigating diving takeoffs (Fig. 1), it is necessary to determine subject-specific model parameters. These include: 1) springboard, 2) segmental inertia, 3) strength, 4) wobbling mass, and 5) foot-springboard interface parameters. The aim of this study was to determine such parameters either directly from measurements or indirectly using an angle-driven model. Subject-specific parameters were determined from an elite female diver who provided informed consent. Testing procedures were approved by the University Ethical Advisory Committee. The vertical behaviour of the springboard was modelled as a linear mass-spring system with no damping and with stiffness as a linear function of foot placement. The stiffness and effective board mass were measured using a dynamic board loading method (Miller and Jones, 1999: Research Quarterly for Exercise and Sport, 70, 395–400). The horizontal deflection was a quadratic function of the vertical deflection and the board angle was a linear function of the vertical deflection. Body segmental inertias were calculated from 95 anthropometric measurements of the diver using a mathematical model of the human body (Yeadon, 1990: Journal of Biomechanics, 23, 67–74). To ensure that the torque generators produced realistic joint torques, maximum isometric and isovelocity torques of the diver were obtained using an isokinetic dynamometer. Movements measured included flexion and extension of shoulder, hip, knee and ankle. A 10parameter fit was used to express torque as a function of joint angle and angular velocity. Wobbling masses were included in the shank, thigh and trunk segments to model the movement of soft tissues during impact. The wobbling mass inertias were calculated from body composition and density reported in the literature and scaled to the diver. Each wobbling mass was attached to the body segment through two pairs of non-linear damped springs. Initial estimates of stiffness and damping were chosen so as to produce appropriate displacement and oscillation frequency. The elastic properties of the foot-springboard interface were represented by three pairs of spring-dampers acting on the heel, ball and toes. The stiffness and damping of these elastic elements, along with the refined estimation ofwobblingmass parameters and springboard stiffness, were determined using an angle-driven model. This was achieved by driving the model with joint angle time histories obtained from 200 Hz video recordings of diving performance from a one-metre springboard and minimising the difference in orientation and linear and angular momentum between simulation and performance using the Simulated Annealing optimisation algorithm (Corana et al., 1987: ACM Transactions on Mathematical Software, 13, 262–280). Four dives with minimum and maximum angular momentum in the Fig. 1. Simulation model of a springboard and a diver. Journal of Sports Sciences, 2005, 23, 93–223 Journal of Sports Sciences ISSN 0264-0414 print/ISSN 1466-447X online # 2005 Taylor & Francis Group Ltd DOI: 10.1080/02640410512331334413 forward and reverse groups were used to obtain a common set of parameters. The mean difference between simulation and performance was 8.3%. This paper described how subject-specific parameters could be measured experimentally or determined indirectly using an angle-driven model. These model parameters will then be used in a torque-driven model which, after satisfactory evaluation, will be used to investigate diving takeoff techniques and to optimise performance. Acknowledgment: This study was supported by the International Society of Biomechanics. 21. Strategies for maximum velocity movements in relation to reaction time and performance