The influence of foreperiod duration on the preparation and control of sequential aiming movements.

Reaction time (RT) and movement times (MTs) to the first target are typically longer for two-target sequential movements compared to one-target movements. While this one-target advantage has been shown to be dependent on the availability of advance information about the numbers of targets, there has been no systematic investigation of how foreperiod duration (i.e., interval between presentation of the target(s) and stimulus) influences the planning and execution of sequential movements. Two experiments were performed to examine how the one-target advantage is influenced by the availability and timing of advance target information. In Experiment 1, participants performed one- and two-target movements in two separate blocks. In Experiment 2, target conditions were randomised from trial to trial. The interval between target(s) appearing and stimulus tone (i.e., foreperiod) was varied randomly (0, 500, 1,000, 1,500, and 2,000 ms). The results of Experiment 1 revealed that while the one-target advantage in RT was not influenced by foreperiod duration, the one-target advantage in MT increased as foreperiod duration increased. The variability of endpoints at the first target was greater in the two- compared to one-target condition. In Experiment 2, the one-target advantage in both RT and MT increased as the length of the foreperiod increased. However, there was no difference in limb trajectory variability between target conditions. The implication of these findings for theories of motor planning and execution of multiple segment movements is discussed.

Influence of motor imagery training on hip abductor muscle strength and bilateral transfer effect.

Motor imagery training could be an important treatment of reduced muscle function in patients and injured athletes. In this study, we investigated the efficacy of imagery training on maximal force production in a larger muscle group (hip abductors) and potential bilateral transfer effects. Healthy participants (n = 77) took part in two experimental studies using two imagery protocols (∼30 min/day, 5 days/week for 2 weeks) compared either with no practice (study 1), or with isometric exercise training (study 2). Maximal hip abduction isometric torque, electromyography amplitudes (trained and untrained limbs), handgrip strength, right shoulder abduction (strength and electromyography), and imagery capability were measured before and after the intervention. Post intervention, motor imagery groups of both studies exhibited significant increase in hip abductors strength (∼8%, trained side) and improved imagery capability. Further results showed that imagery training induced bilateral transfer effects on muscle strength and electromyography amplitude of hip abductors. Motor imagery training was effective in creating functional improvements in limb muscles of trained and untrained sides.

Testing anxiety's effect on movement planning and correction: Online upper-limb corrections are not completely automatic.

Via three experiments, we investigated heightened anxiety's effect on the offline planning and online correction of upper-limb target-directed aiming movements. In Experiment 1, the majority of task trials allowed for the voluntary distribution of offline planning and online correction to achieve task success, while a subset of cursor jump trials necessitated the use of online correction to achieve task success. Experiments 2 and 3 replicated and elaborated Experiment 1 by assessing movement-specific reinvestment propensity and manipulating the self-control resources of participants. This allowed more detailed inference of cognitive resource utilisation to tease apart the effects of conscious processing and distraction-based anxiety mechanisms. For the first time, we demonstrate that: anxiety-induced online-to-offline motor control shifts can be overridden when the need for online correction is necessitated (i.e., in jump trials); anxiety-induced online-to-offline shifts seem to be positively predicted by conscious processing propensity; and optimal spatial efficacy of limb information-based online correction seems to require cognitive resources. We conclude that long-standing definitions of limb information-based online correction require revision, and that both conscious processing and distraction theories appear to play a role in determining the control strategies of anxiety induced upper limb target directed aiming movements.

Sequential aiming in pairs: the multiple levels of joint action.

The task constraints imposed upon a co-actor can often influence our own actions. Likewise, the observation of somebody else's movements can involuntarily contaminate the execution of our own movements. These joint action outcomes have rarely been considered in unison. The aim of the present study was to simultaneously examine the underlying processes contributing to joint action. We had pairs of participants work together to execute sequential aiming movements between two targets-the first person's movement was contingent upon the anticipation of the second person's movement (leader), while the second person's movement was contingent upon the direct observation of the first person's movement (follower). Participants executed separate blocks of two-target aiming movements under different contexts; that is, solely on their own using one (2T1L) and two (2T2L) of their upper limbs, or with another person (2T2P). The first movement segment generally indicated a more abrupt approach (shorter time after peak velocity, greater displacement and magnitude of peak velocity), which surprisingly coincided with lower spatial variability, for the 2T2P context. Meanwhile, the second segment indicated a similar kinematic profile as the first segment for the 2T2P context. The first movement of the leader appeared to accommodate the follower for their movement, while the second movement of the follower was primed by the observation of the leader's movement. These findings collectively advocate two distinct levels of joint action including the anticipation (top-down) and mapping (bottom-up) of other people's actions.

Does high state anxiety exacerbate distractor interference?

Attentional Control Theory states that anxiety can cause attention to be allocated to irrelevant sources of information by hindering the ability to control attention and focus on the information that matters. In a separate line of inquiry, action-centred views of attention state that non-target distractors involuntarily activate response codes that may cause interference with target-directed movements (distractor interference effect). Due to the proposed negative effects of anxiety on attentional control, we examined whether anxiety could also modulate distractor interference. Participants executed target-directed aiming movements to one of three targets with the potential of a distractor being presented at near or far locations. Distractors were presented at different times with respect to the target presentation in order to explore the excitatory (0, -100 ms) and inhibitory (-850 ms) processing of the distractor. As a broad indication of the effect of anxiety, the analysis of no distractor trials indicated a lower proportion of time and displacement to reach peak velocity under high compared to low anxiety conditions. Meanwhile, the typical excitatory influence of the distractors located near, compared to far, at a short distractor-onset asynchrony was found in movement time and overall response time. However, this distractor excitation was even greater under high compared to low anxiety in the reaction time component of the response. These findings broadly implicate the attentional control perspective, but they further indicate an influence of anxiety on the excitation rather than inhibition of responses.

Lets go surfing now, everybody's learning how; attentional strategies on expert and novice surfing performance under both practice and competition conditions.

Research suggests an external focus of attention (EFOA) promotes effective performance and learning compared to an internal focus of attention (IFOA), with explanations proposed by the constrained action hypothesis (CAH) and OPTIMAL theory of motor learning. Specifically, it is proposed that adopting an EFOA prevents the constraining of normally automatic control processes and subsequent performance decrements (typically observed when individuals adopt an IFOA) by simultaneously reducing self-focus strategies and enhancing goal-action coupling. The present study attempted to fill this research lacuna by examining the CAH and OPTIMAL theory in a complex, ecologically valid, motor task under both low and high-pressured conditions. In two separate experiments, novice (n = 23) and advanced (n = 21) surfers completed a surfing task in an artificial Wavegarden under either EFOA or IFOA instructions. Experimental phases included a pre-test, acquisition and competition transfer. Results revealed that advanced and novice surfing performance benefited from adopting an EFOA in both normal and competitive situations. These findings are discussed in terms of the theoretical implications for the CAH and OPTIMAL theory, in addition to the anxiety literature. Reference to applied implications when instructing and performing within ecologically valid surfing settings are also presented.

Representational Momentum in the Expertise Context: Support for the Theory of Event Coding as an Explanation for Action Anticipation.

This study aimed to extend the notion of the theory of event coding as an explanation of action anticipation in expert sport performers. This was achieved by investigating the degree with which automatic anticipation depends on the ecological congruency between the perceived action and its distal effect. In a novel approach, the representational momentum paradigm was adopted to address this notion. Expert (N = 16) and novice (N = 20) rugby players observed a dynamic video of a short pass that was displayed as either toward or away from a receiver. Following an occlusion interval, participants were required to judge whether the video resumed at the same place, further forward or further backward than its original stopping place. Experts demonstrated stronger anticipatory tendencies when the action was directed toward the receiver. This relationship was modulated by a leftward directional bias that is discussed in the context of a bias in viewing behavior that is underpinned by attention. Novice anticipatory tendencies were independent of context. These findings show support for the extension of the theory of event coding.

Impact of attentional focus on motor performance within the context of "early" limb regulation and "late" target control.

Directing attention to the effect of one's movement (external focus) has been shown to aid performance compared to directing attention to the movement itself (internal focus). This finding has been predominantly explained by an external focus promoting action planning and automatic movement control, while an internal focus acts to constrain movement (constrained action hypothesis [CAH]). In a separate line of research, the multiple control process model states that early movement phases involve anticipated and feedforward processes, while late movement phases explicitly incorporate external afferent information. We hypothesized that enhanced planning and automatic movement control would manifest from an external/distal focus compared to internal/proximal focus. The present study had participants execute fast and accurate movements to a single target using a digitizing graphics tablet that translated movements to a screen. Participants were instructed to focus on the end target location (external-distal), movement of the cursor (external-proximal), and movement of the limb (internal-proximal). It was found that the external-distal focus generated a shorter time to initiate and execute movements (indicating enhanced movement planning) compared to the external- and internal-proximal conditions. In addition, only the external proximal focus revealed a reduction in spatial variability between peak velocity and movement end (indicating greater online control). These findings indicate that advances in action planning and online control occur when adopting an external-distal focus. However, there were some benefits to online control when adopting an external-proximal focus. We propose that an external-distal focus promotes action-effect principles, where there is a greater contribution of anticipatory feedforward processes that limit the need for late online control.

What's your number? The effects of trial order on the one-target advantage.

When moving our upper-limb towards a single target, movement times are typically shorter than when movement to a second target is required. This is known as the one-target advantage. Most studies that have demonstrated the one-target advantage have employed separate trial blocks for the one- and two-segment movements. To test if the presence of the one-target advantage depends on advance knowledge of the number of segments, the present study investigated whether the one-target advantage would emerge under different trial orders/sequences. One- and two-segment responses were organized in blocked (i.e., 1-1-1, 2-2-2), alternating (i.e., 1-2-1-2-1-2), and random (i.e., 1-1-2-1-2-2) trial sequences. Similar to previous studies, where only blocked schedules have typically been utilized, the one-target advantage emerged during the blocked and alternate conditions, but not in the random condition. This finding indicates that the one-target advantage is contingent on participants knowing the number of movement segments prior to stimulus onset.

Changing performance pressure between training and competition influences action planning because of a reduction in the efficiency of action execution.

Background and objectives Specificity of practice proposes optimal performance is linked to the conditions under which learning occurred. The present study investigated this effect within a pressure context to determine whether offline and/or online control processes develop specificity through the introduction or removal of performance pressure. Methods Forty novices practiced a two-dimensional stimulus-response discrimination task in one of four groups; two control (control-control and anxiety-anxiety) and two experimental (control-anxiety and anxiety-control). In the experimental groups, participants experienced a switch in conditions of pressure both early and late in practice, i.e., practiced in low-pressure and transferred to high-pressure (control-anxiety group) or the reverse of this (anxiety-control group). Results A significant acquisition-to-transfer decrement in performance occurred for both experimental groups. This offers support for a pressure-performance specificity effect because a change in conditions of pressure (regardless if that was an increase or decrease) resulted in performance decrements. Furthermore, the reaction time measure of offline control was affected by the change to a significantly greater extent than the movement time measure of online control. Conclusions Increases in offline control processes was a performance strategy adopted to combat the disruption that pressure caused to the processes associated with adjusting or planning movements online.

The benefit of punishment sensitivity on motor performance under pressure.

OBJECTIVE: Humans are often required to perform demanding cognitive and motor tasks under pressure. However, in such environments there is considerable interindividual variability in the ability to successfully execute actions. Here, we consider how individual differences in self-reported sensitivity to punishment influence skilled motor performance under pressure and whether this relationship is moderated by the temporal detection of threat. METHOD: Across two studies, 160 UK participants (Study 1: N = 80, Mage = 21.6, 52 males; Study 2: N = 80, Mage = 24.95, 45 males) performed a precision-grip task and received either early or late warning of an upcoming stressful manipulation involving social evaluation and performance-dependent incentives. RESULTS: In both studies, we report an interaction where punishment sensitivity was adaptive for motor performance only when threats were detected early and there was opportunity to prepare for the upcoming stressor. Further, our results suggest that the benefits of punishment sensitivity are likely underpinned by the effective use of cognitive strategies. CONCLUSION: Heightened sensitivity to punishment is adaptive for performance under pressure, provided threats are detected early and effective cognitive strategies are implemented.

New evidence of relative age effects in "super-elite" sportsmen: a case for the survival and evolution of the fittest.

The relative age effect (RAE) describes an overrepresentation of players born early (Q1) in a selection year and is highly prevalent within youth sport pathways. However, a dearth of research has investigated the RAE at the "super-elite" level. The present research assessed the presence of RAE in super-elite performers. Study 1 investigated RAEs in the world's best international Test cricketers (N = 262) over a 20-year period according to a robust and stringent "super-elite" criteria. Results revealed the RAE (Q1) when all disciplines were combined. Upon closer examination, this effect was also observed for the batting and spin bowling disciplines, whereas no RAE was found for the pace bowling discipline. Study 2 investigated RAEs in super-elite rugby union players (N = 691) over a 20 year period. Results revealed the RAE for backs (Q1) and a reversal of the traditional RAE (Q4) for forwards, and when all rugby union positions were combined. These findings provide new evidence of RAEs at the super-elite level and present both inter and intra sports differences. Potential explanations for these findings are explored, owing to the survival and evolution of the fittest concepts, and the implications for future research and applied practice are presented.

The interaction between practice and performance pressure on the planning and control of fast target directed movement.

Pressure to perform often results in decrements to both outcome accuracy and the kinematics of motor skills. Furthermore, this pressure-performance relationship is moderated by the amount of accumulated practice or the experience of the performer. However, the interactive effects of performance pressure and practice on the underlying processes of motor skills are far from clear. Movement execution involves both an offline pre-planning process and an online control process. The present experiment aimed to investigate the interaction between pressure and practice on these two motor control processes. Two groups of participants (control and pressure; N = 12 and 12, respectively) practiced a video aiming amplitude task and were transferred to either a non-pressure (control group) or a pressure condition (pressure group) both early and late in practice. Results revealed similar accuracy and movement kinematics between the control and pressure groups at early transfer. However, at late transfer, the introduction of pressure was associated with increased performance compared to control conditions. Analysis of kinematic variability throughout the movement suggested that the performance increase was due to participants adopting strategies to improve movement planning in response to pressure reducing the effectiveness of the online control system.

Representational momentum reveals visual anticipation differences in the upper and lower visual fields.

Recent empirical research has revealed differences in functional capacity between the upper and lower visual fields (VFs), with the lower VF exhibiting superiority in visual perception skills. Similarly, functional differences between the left and right hemispheres elicit a predominance for visuospatial processing in the left visual field (left VF). Both anatomical as well as evolutionary arguments have been adopted in accounting for these variations in function. Preceding upper and lower VF research has typically investigated either static stimulus perception or the visual processing of upper limb action. The aim of the current research was to investigate whether the lower VF benefits associated with limb control transcend to visual anticipation (the perception of motion). Methods were based on Khan and Lawrence (Exp Brain Res 164:395-398, 2005), who investigated upper/lower VF differences in visuomotor control, but utilising a representational momentum paradigm to isolate perceptual processes. Thirty-two participants were randomised into either a left or right VF group and completed a perceptual computer-based task in the upper and lower VF, where they were required to judge the final position of a moving object before it disappeared. Two aspects of the distributions of same responses were then analysed; the central tendency (weighted means) and the variability. Results revealed that in the left VF, weighted means for the lower VF were significantly greater than for the upper VF [t(14) = 2.242, p = 0.042]. In both left and right VFs, variability was greater in the upper compared to lower VF. This provides new findings regarding visual processes in the different visual fields. While visual search and large scene perception has been found to be superior in the upper VF, here we find that visual anticipation, like target-directed visuomotor skill, is superior in the lower VF.

Practice with anxiety improves performance, but only when anxious: evidence for the specificity of practice hypothesis.

We investigated for the first time whether the principles of specificity could be extended to the psychological construct of anxiety and whether any benefits of practicing with anxiety are dependent on the amount of exposure and timing of that exposure in relation to where in learning the exposure occurs. In Experiment 1, novices practiced a discrete golf-putting task in one of four groups: all practice trials under anxiety (anxiety), non-anxiety (control), or a combination of these two (i.e., the first half of practice under anxiety before changing to non-anxiety conditions, anxiety-control, or the reverse of this, control-anxiety). Following acquisition, all groups were transferred to an anxiety condition. Results revealed a significant acquisition-to-transfer decrement in performance between acquisition and transfer for the control group only. In Experiment 2, novices practiced a complex rock climbing task in one of the four groups detailed above, before being transferred to both a high-anxiety condition and a low-anxiety condition (the ordering of these was counterbalanced across participants). Performance in anxiety transfer was greater following practice with anxiety compared to practice without anxiety. However, these benefits were influenced by the timing of anxiety exposure since performance was greatest when exposure to anxiety occurred in the latter half of acquisition. In the low-anxiety transfer test, performance was lowest for those who had practiced with anxiety only, thus providing support for the specificity of practice hypothesis. Results demonstrate that the specificity of learning principle can be extended to include the psychological construct of anxiety. Furthermore, the specificity advantage appears dependent on its timing in the learning process.

Sequential aiming movements and the one-target advantage in individuals with Down syndrome.

Research has revealed that individuals with Down syndrome (DS) have elevated reaction times, longer movement times, and greater movement errors during single-target single-limb actions compared to their typically developing (TD) peers. These perceptual-motor impairments have been attributed to both central processes and the physical phenotype associated with DS. The purpose of the present study was to directly investigate these possible central and peripheral deficits by examining how individuals with DS plan and execute more complex movements. Three groups (DS, TD, and individuals with an undifferentiated intellectual disability; UID) of 8 participants completed a single target movement, a two-target movement performed by a single arm, and a two-target movement where the first movement was performed with one arm and the second movement performed with the other arm. For all groups and all conditions, movement times revealed a one-target advantage (OTA). Specifically, times to the first target were longer in the two-target responses compared to the single-target response. In general, the OTA finding reveals that persons with DS utilise planning strategies similar to their TD peers when performing sequential actions involving two targets and two arms. Furthermore, because the OTA was observed in both the single- and two-arm two-target responses the interference in movement one associated with having to make a subsequent movement is not due to peripheral processes associated with single limb constraints. Rather, individuals with DS treat movements within a sequence as functionally dependent. Thus, the central processes associated with timing the implementation of the second element of the movement appear to be responsible for the interference that leads to the OTA.

The effect of state anxiety on the online and offline control of fast target-directed movements.

In target-directed aiming, afferent information is used to adjust limb trajectories during movement execution (i.e. online) and to enhance the programming of subsequent trials (i.e. offline). The objective of the present study was to determine the influence of state anxiety on both online and offline afferent information processing for the first time. Participants practiced either a directional aiming task (Experiment 1) or an amplitude aiming task (Experiment 2) without anxiety before being transferred to a high anxiety condition. In both experiments, results revealed that anxiety resulted in a decrement in performance. Furthermore, use of afferent information to adjust movement trajectories online was disrupted when movements were performed with anxiety, whereas there were no differences in the offline processing of afferent information between the low anxiety and high anxiety conditions.

The Movement Kinematics and Learning Strategies Associated with Adopting Different Foci of Attention during Both Acquisition and Anxious Performance.

Research suggests that implicit strategies adopted during learning help prevent breakdown of automatic processes and subsequent performance decrements associated with the presence of pressure. According to the Constrained Action Hypothesis, automaticity of movement is promoted when adopting an external focus of attention. The purpose of the current experiment was to investigate if learning with an external focus of attention can enhance performance under subsequent pressure situations through promoting implicit learning and automaticity. Since previous research has generally used outcome measures of performance, the current study adopted measures of movement production. Specifically, we calculated within-subject variability in trajectory velocity and distance traveled every 10% of movement time. This detailed kinematic analysis allowed investigation into some of the previously unexplored mechanisms responsible for the benefits of adopting an external focus of attention. Novice participants performed a 2.5 m golf putt. Following a pre-test, participants were randomly assigned to one of three focus groups (internal, external, control). Participants then completed 400 acquisition trials over two consecutive days before being subjected to both a low anxiety and high anxiety (HA) transfer test. Dependent variables included variability, number of successful putts and mean radial error. Results revealed that variability was greater in the internal compared to the external and control groups. Putting performance revealed that all groups increased performance following acquisition. However, only the control group demonstrated a decrement in performance in the HA transfer test. These findings suggest that adopting an appropriate focus of attention during learning can prevent choking; with an external focus inhibiting the breakdown of automatic processes and an internal focus acting as a self-focus learning strategy and thus desensitizing individuals to anxiety effects.

The reliance on visual feedback for online and offline processing.

The objective of the current study was to determine whether the reliance on visual feedback that develops with practice is to due utilizing vision to adjust trajectories during movement execution (i.e., online) and/or to enhance the programming of subsequent trials (i.e., offline). Participants performed a directional aiming task with either vision during the movement, dynamic feedback of the trajectory of the movement or the movement endpoint. The full vision condition was more accurate during practice than the other feedback conditions but suffered a greater decrement in performance when feedback was removed. In addition, the reliance on trajectory feedback was greater compared with the endpoint feedback. It appears that the reliance on visual feedback that develops with practice was due to both online and offline processing.

The dual role of vision in sequential aiming movements.

Previous research has demonstrated that movement times to the first target in sequential aiming movements are influenced by the properties of subsequent segments. Based on this finding, it has been proposed that individual segments are not controlled independently. The purpose of the current study was to investigate the role of visual feedback in the interaction between movement segments. In contrast to past research in which participants were instructed to minimize movement time, participants were set a criterion movement time and the resulting errors and limb trajectory kinematics were examined under vision and no vision conditions. Similar to single target movements, the results indicated that vision was used within each movement segment to correct errors in the limb trajectory. In mediating the transition between segments, visual feedback from the first movement segment was used to adjust the parameters of the second segment. Hence, increases in variability that occurred from the first to the second target in the no vision condition were curtailed when visual feedback was available. These results are discussed along the lines of the movement constraint and movement integration hypotheses.