Paul S. Holmes

The PETTLEP Approach to Motor Imagery: A Functional Equivalence Model for Sport Psychologists

Abstract This paper supports the contention that the brain stores memories in the form of a central representation that is accessed by both physical preparation and execution and, more importantly, by motor imagery associated with this preparation and execution. Considerable evidence in support of shared central and vegetative structures suggests that sport psychologists should consider more closely aspects of the performers responses to the physical skill when providing imagery interventions and not rely on “traditional,” more clinically orientated, methods of delivery. Many texts provide a schedule of factors and techniques for psychologists, athletes, and coaches to consider but with a limited theoretical explanation of why these factors are the crucial concerns. We, therefore, propose an evidence-based, 7-point checklist that includes: physical, environmental, task, timing, learning, emotional, and perspective elements of imagery delivery highlighting the minimum requirement areas in which sport psychologists should monitor the equivalence to the physical task in order to enhance the efficacy of their practice.

A Neuroscientific Review of Imagery and Observation Use in Sport

Imagery and observation are multicomponential, involving individual difference characteristics that modify the processes. The authors propose that both imagery and observation function by offering effective routes to access and reinforce neural networks for skilled performance. The neural isomorphism with overt behaviors offers a tempting mechanism to explain the beneficial outcomes of the 2 processes. However, several limitations related to imagery indicate the possibility that imagery may not be as efficacious as the literature would indicate. The authors propose observation-based approaches to offer more valid and effective techniques in sport psychology and motor control.

The role of effort in influencing the effect of anxiety on performance : Testing the conflicting predictions of processing efficiency theory and the conscious processing hypothesis

The aim of this study was to test the conflicting predictions of processing efficiency theory (PET) and the conscious processing hypothesis (CPH) regarding efforts role in influencing the effects of anxiety on a golf putting task. Mid-handicap golfers made a series of putts to target holes under two counterbalanced conditions designed to manipulate the level of anxiety experienced. The effort exerted on each putting task was assessed though self-report, psychophysiological (heart rate variability) and behavioural (pre-putt time and glances at the target) measures. Performance was assessed by putting error. Results were generally more supportive of the predictions of PET rather than the CPH as performance was maintained for some performers despite increased state anxiety and a reduction in processing efficiency. The findings of this study support previous research suggesting that both theories offer useful theoretical frameworks for examining the relationship between anxiety and performance in sport.

The relationship between corticospinal excitability during motor imagery and motor imagery ability

It is commonly reported that transcranial magnetic stimulation (TMS) of the motor cortex during action observation and motor imagery results in increases in the amplitude of motor evoked potentials (MEPs) in muscles specific to the observed or imagined action. This study aimed to determine whether MEP amplitude was related to the motor imagery ability of participants. Participants were 15 healthy, right-handed adults (five male), with a mean age of 29.7 years. Motor imagery ability was measured using the Vividness of Movement Imagery Questionnaire-2 (VMIQ-2) and a hand rotation task. TMS was delivered during observation and imagery of a finger-thumb opposition sequence and MEPs were measured in the abductor pollicis brevis. Significant increases in MEP amplitude, from baseline, were recorded during observation and imagery conditions. The change in amplitude to both observation and imagery was expressed as a percentage of baseline amplitude. There was a significant correlation between MEP change for the imagery condition and imagery ability, with greater change linked to more vivid images and faster response times. The relationship between MEP change for the observation condition and imagery ability was less salient. This is the first study to show that the strength of corticospinal activation during imagery, which may be a determinant of the effectiveness of imagery training, is related to imagery ability in the general population, and has implications for clinical programs.

Quiet eye duration and gun motion in elite shotgun shooting.

INTRODUCTION No literature exists to document skill-related differences in shotgun shooting and whether these may be a function of eye movements and control of gun motion. We therefore conducted an exploratory investigation of the visual search behaviors and gun barrel kinematics used by elite and subelite shooters across the three shotgun shooting subdisciplines. METHODS Point of gaze and gun barrel kinematics were recorded in groups of elite (n = 24) and subelite (n = 24) shooters participating in skeet, trap, and double trap events. Point of gaze was calculated in relation to the scene, while motion of the gun was captured by two stationary external cameras. Quiet eye (final fixation or tracking gaze that is located on a specific location/object in the visual display for a minimum of 100 ms) duration and onset were analyzed as well as gun motion profiles in the horizontal and vertical planes. RESULTS In skeet, trap, and double trap disciplines, elite shooters demonstrated both an earlier onset and a longer relative duration of quiet eye than their subelite counterparts did. Also, in all three disciplines, quiet eye duration was longer and onset earlier during successful compared with unsuccessful trials for elite and subelite shooters. Kinematic analyses indicated that a slower movement of the gun barrel was used by elite compared with subelite shooters. CONCLUSIONS Overall, stable gun motion and a longer quiet eye duration seem critical to a successful performance in all three shotgun disciplines.

Anxiety, movement kinematics, and visual attention in elite-level performers.

We tested the predictions of Attentional Control Theory (ACT) by examining the effect of anxiety on attention control and the subsequent influence on both performance effectiveness and performance efficiency within a perceptual-motor context. A sample (N = 16) of elite shotgun shooters was tested under counterbalanced low (practice) and high (competition) anxiety conditions. A head-mounted, corneal reflection system allowed point of gaze to be calculated in relation to the scene, while motion of the gun was evaluated using markers placed on the barrel which were captured by two stationary cameras and analyzed using optical tracking software. The quiet eye (QE) duration and onset were analyzed along with gun barrel displacement and variability; performance outcome scores (successful vs. unsuccessful) were also recorded. QE (Vickers, 1996) is defined as the final fixation or tracking gaze that is located on a specific location/object in the visual display for a minimum of 100 ms. Longer QE durations have been linked to successful performance in previous research involving aiming tasks. Participants demonstrated shorter quiet eye durations, and less efficient gun motion, along with a decreased performance outcome (fewer successful trials) under high compared with low anxiety conditions. The data support the predictions of ACT with anxiety disrupting control processes such that goal-directed attention was compromised, leading to a significant impairment in performance effectiveness.

Pre-shot EEG alpha-power reactivity during expert air-pistol shooting : A comparison of best and worst shots

The aim of this study was to examine the proposal that pre-shot occipital electroencephalogram (EEG) alphapower reactivity would not only associate with, but also have a causal role in, the relative success of performance outcome in expert air-pistol shooting. Six expert air-pistol shooters performed a sixty-shot match, individually, while electroencephalograms were captured from occipital and anterior-temporal electrode sites during the aiming period (3 2 2 s epochs) before shot release. The five best shots and five worst shots were selected for each shooter on the basis of four shot quality indicators, and pre-shot EEG alpha power for best shots was compared with that of worst shots. Occipital EEG alpha power was found to increase during epochs 1–3 before best shots, but to decrease before worst shots; it was significantly greater during the final pre-shot epoch of best shots. This finding suggests that visual attention to the pistol and target was gradually suppressed during the pre-shot period of best shots, whereas it gradually increased before worst shots. In addition, significantly greater EEG alpha power was found at the left than at the right anterior-temporal site, lending support to the robust findings of previous target-sport studies. We conclude that the participants were able to shoot at the target with greatest success when not having maximal visual attention on where the pistol was aimed and that suppression of visual attention during the final seconds of the pre-shot period is a necessary prerequisite for automatic shot execution, as controlled by mechanisms of intention.

Quiet Eye Training in a Visuomotor Control Task

INTRODUCTION Several researchers have reported the importance of maintaining a longer final fixation on the target (termed the quiet eye period, QE) before performing an aiming task. We present an innovative, perceptual training intervention intended to improve the efficiency of gaze behavior (i.e., QE) in shotgun shooting. METHODS A sample of 20 international-level skeet shooters were assigned equally to one of two ability-matched groups based on their pretest shooting scores. A perceptual training group participated in a four-step preshot routine alongside three video feedback sessions involving their own gaze behaviors and those of an expert model in an effort to positively influence QE behaviors. A control group received video feedback of performance but without the addition of feedback on QE behaviors. Participants completed pretests and posttests along with an 8-wk training intervention. RESULTS Subjects of the perceptual training group significantly increased their mean QE duration (397 vs 423 ms), used an earlier onset of QE (257 vs 244 ms), and recorded higher shooting accuracy scores (62 vs 70%) from pretest to posttest. Participants in the perceptual training group significantly reduced gun barrel displacement and absolute peak velocity on the posttest compared with the pretest, although neither variable was overtly trained. A transfer test based on performance during competition indicated that perceptual training significantly improved shooting accuracy from before to after the intervention. No pretest to posttest differences were observed for the control group on the measures reported. CONCLUSIONS The results demonstrate the effectiveness of QE training in improving shooting accuracy and developing a more efficient visuomotor control strategy.The findings have implications for future research on training visuomotor behaviors, attention, and gaze orientation during the performance of aiming tasks.

Functional equivalence or behavioural matching? A critical reflection on 15 years of research using the PETTLEP model of motor imagery

Motor imagery, or the mental rehearsal of actions in the absence of physical movement, is an increasingly popular construct in fields such as neuroscience, cognitive psychology and sport psychology. Unfortunately, few models of motor imagery have been postulated to date. Nevertheless, based on the hypothesis of functional equivalence between imagery, perception and motor execution, Holmes and Collins in 2001 developed the PETTLEP model of motor imagery in an effort to provide evidence-based guidelines for imagery practice in sport psychology. Given recent advances in theoretical understanding of functional equivalence, however, it is important to provide a contemporary critical reflection on motor imagery research conducted using this model. The present article addresses this objective. We begin by explaining the background to the development of the PETTLEP model. Next, we evaluate key issues and findings in PETTLEP-inspired research. Finally, we offer suggestions for, and new directions in, research in this field.

Investigating central mechanisms underlying the effects of action observation and imagery through transcranial magnetic stimulation

ABSTRACT Sport and exercise psychologists provide some interventions for clients based on limited direct evidence and partial understanding of the mechanisms that underpin their efficacy. The authors review a recent technique, transcranial magnetic stimulation (TMS), which offers a tested procedure for investigating cortical activity during observation and imagery processes. They provide a detailed description of the TMS protocol and highlight some of the key studies that inform sport and exercise psychology research. Finally, the authors offer some thoughts on the direct application to practice.