Benefits of an external focus of attention: Common coding or conscious processing?

Motor learning in golf-a systematic review

Golf is a sport that consists of complex movement skills that need to be executed with utmost precision. Consequently, motor skill learning plays a crucial role in golf, and large numbers of studies address various methods of motor learning. In the present review, we give a systematic overview of randomized controlled trials (RCTs) on motor learning of golf-specific motor skills. Three electronic databases were searched for RCTs looking at the effect of at least one learning method on performance in a golf-specific motor task. We grouped the studies depending on the learning strategies "cognitive training", "practice scheduling", "augmented feedback", "implicit and explicit learning" and "focus of attention". Fifty-two RCTs met the eligibility criteria and were included in the systematic review. Superior methods within their respective strategies were an external focus of attention and increasing contextual interference, as well as errorless learning. For "cognitive training" and "augmented feedback", no single method can be considered the most favorable. The overall biggest limitations were the lack of statistical power for more than half of the RCTs, and the fact that most studies of the present review investigated simple putting tasks in novices only. Although we have shown superiority of specific learning methods, transferability of the recommendations that can be derived from simple golf tasks in novices to sport-specific tasks in advanced players still has to be demonstrated and require study designs with the intention to provide practical recommendations for coaches and athletes in the sport of golf.

Do attentional focus cues affect the type or number of explicit rules? Proof of concepts of the self-invoking trigger or explicit knowledge hypotheses

Internal focus has been shown to be detrimental to performance by disrupting the motor system, whereas external focus enhances performance by promoting automaticity. One hypothesis, which explains the underlying mechanism of the disruption of the motor system, proposes that internal focus affects the type of thoughts (explicit rules) by invoking self-conscious, evaluative thoughts (McKay et al., 2015). In contrast, another hypothesis proposes that internal focus increases the number of explicit rules, loading working memory (Poolton et al., 2006). To examine the competing hypotheses, neurotypical young adults (22.98 ± 4.46 years old, n = 20 males, n = 40 females) were assigned to one of three groups: external focus (n = 20), internal focus (n = 20), and control (n = 20) groups, and practiced a reciprocal aiming task for two days with retention/transfer tests. Between trials, participant's thoughts were evaluated by an open-ended questionnaire. The type of explicit rules was analyzed using a chi-square test, and the number of explicit rules was analyzed using a mixed-effect Poisson regression. The results showed that external focus resulted in a greater proportion of explicit rules about the task and a lesser proportion of self-evaluative thoughts. The number of explicit rules did not differ between groups. Our results suggest that external focus may strengthen focus on task-relevant features, while internal focus moves people's attention away from important features, potentially explaining why the motor system is disrupted by internal focus.

Training prosthesis users to switch between modes of a multi-articulating prosthetic hand

PURPOSE

Producing triggers to switch between modes of myoelectric prosthetic hands has proven to be difficult. We evaluated whether digital training methods were feasible in individuals with an upper limb defect (ULD), whether myosignals in these individuals differ from those of non-impaired individuals and whether acquired skills transfer to prosthesis use.

MATERIALS AND METHODS

Two groups participated in a 9-day pre-test-post-test design study with seven 45-minute training sessions. One group trained using a serious game, the other with their myosignals digitally displayed. Both groups also trained using a prosthesis. The pre- and post-tests consisted of an adapted Clothespin Relocation Test and the spherical subset of the Southampton Hand Assessment Procedure. After the post-test, the System Usability Scale (SUS) was administered. Clinically relevant performance measures and myosignal features were analysed.

RESULTS

Four individuals with a ULD participated. SUS-scores deemed both training methods feasible. Three participants produced only a few correct triggers. Myosignals features indicated larger variability for individuals with a ULD compared to non-impaired individuals (previously published data [1]). Three participants indicated transfer of skill.

CONCLUSIONS

Even though both training methods were deemed feasible and most participants showed transfer, seven training sessions were insufficient to learn reliable switching behaviour.Trial registration: The study was approved by the medical ethics committee of the University Medical Center Groningen (METc 2018.268).Implications for rehabilitationSwitching between pre-programmed modes of a myoelectric prosthetic hand can be learned, however it does require training.Serious games can be considered useful training tools for trigger production in early phases of myoelectric prosthesis control training.In order to evoke transfer of skill from training to daily life both task-specificity and focus of attention during training should be taken into account.

The effect of internal and external focus of attention on tennis skill acquisition in children

Objective

The aim of this study was to examine the effect of internal and external focus attention instructions on learning the tennis groundstroke (forehand-backhand drive) for children.

Methods

A total of 60 (30 girls, 30 boys) children aged 10.24 ± 0.48 years were included in the study. Children were randomly divided into three groups: External Focused Group (EFG), Internal Focused Group (IFG), and Control Group (CG).

Results

In the pre-training tests of tennis skill (TST) and tennis transfer (TTT), there was no significant difference between the three groups (EFG, IFG, and CG) according to one-way ANOVA results (p > 0.05). Significant interaction was determined between groups and measurements in a repeated-measures ANOVA analysis (three groups, three measurements) and TST and TTT (p < 0.01). According to the post-hoc analysis, it was determined that the TST results increased significantly in the EFG compared to the IFG and CG, and there was no significant difference in the TTT between the EFG and IFG, but both groups showed significant improvements compared to the CG.

Conclusion

Instructions to children to focus attention externally facilitate learning the groundstroke (forehand-backhand) technique, which is one of the basic tennis techniques.

The effect of attentional focus instructions on performance and technique in a complex open skill

External focus of attention has been shown to promote more automatic motor control, yielding better performance and more efficient technique, than an internal focus. However, most research has used closed-skill tasks in novices. The extent to which the reported pattern of findings generalises to more complex, time-constrained tasks requires further investigation. In this study, we investigated the effect of attentional focus instructions on performance and technique in an open-skill task in skilled performers. Thirteen skilled cricket batters batted from a ball projector in four conditions, receiving instructions to focus on the movement of their hands (internal focus), the movement of their bat (proximal external focus), the flight of the ball (distal external focus), or no instruction (control). Performance and technique were measured by quality of bat-ball contacts and step length/knee flexion, respectively, whilst playing straight drives. Compared to external focus and control conditions, focusing internally yielded significantly worse batting performance and shorter step lengths, with the largest effects observed between internal and distal external focus conditions. Quality of bat-ball contact data suggested that participants' ability to protect the wicket (as evidenced by more miss/edge shots) was more negatively affected by focusing internally than their ability to play shots to score runs (as evidenced by fewer good bat-ball contacts). Findings suggest that, for skilled performance of open-skill tasks, a distal external focus yields more effective performance and technique compared with focusing internally. Findings highlight the need for further research on attentional focus effects between different skills within specific sports.Highlights A distal external focus of attention enhances performance and technique of skilled cricket batters compared with an internal focus.Providing skilled batters with no instructions yields similar performance benefits to distal external focus instructions.Focusing internally differentially negatively affects skilled cricket batters depending on the strategic intention of the shot being played (e.g. protecting the wicket vs attempting to score runs).

Optimal Training for Movement Acquisition and Transfer: Does "Externally Focused" Visual Biofeedback Promote Implicit Motor Learning?

CONTEXT

Visual biofeedback has been shown to facilitate injury-resistant movement acquisition in adolescent athletes. Visual biofeedback is typically thought to foster implicit learning by stimulating athletes to focus attention externally (on movement outcome). However, biofeedback may also induce explicit learning if the athlete uses the visual information to consciously guide movement execution (via an internal focus).

OBJECTIVE

To determine the degree to which athletes reported statements indicating implicit or explicit motor learning after engaging in a visual biofeedback intervention.

DESIGN

Prospective cohort study.

SETTING

Three-dimensional motion-analysis laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-five adolescent female soccer athletes (age = 15.0 ± 1.5 years, height = 165.7 ± 5.9 cm, mass = 59.4 ± 10.6 kg).

INTERVENTIONS

Standard 6-week neuromuscular training intervention (three 90-minute sessions/wk), with added visual biofeedback sessions (2 sessions/wk). For the biofeedback training, participants performed squatting and jumping movements while interacting with a visual rectangular stimulus that mapped key parameters associated with injury risk. After the last biofeedback session in each week, participants answered open-ended questions to probe learning strategies.

MAIN OUTCOME MEASURE(S)

Responses to the open-ended questions were categorized as externally focused (ie, on movement outcome, suggestive of implicit learning), internally focused (ie, on movement itself, suggestive of explicit learning), mixed focus, or other.

RESULTS

A total of 171 open-ended responses were collected. Most of the responses that could be categorized (39.2%) were externally focused (41.8%), followed by mixed (38.8%) and internally focused (19.4%). The frequency of externally focused statements increased from week 1 (18%) to week 6 (50%).

CONCLUSIONS

Although most statements were externally focused (suggesting implicit learning), the relatively large proportion of internal- and mixed-focus statements suggested that many athletes also engaged in explicit motor learning, especially in early practice sessions. Therefore, biofeedback may affect motor learning through a mixture of implicit and explicit learning.

Attentional Focus Strategies to Improve Motor Performance in Older Adults: A Systematic Review

Previous literature shows the beneficial effects of an external focus of attention on various sports skills in young adults. The objective of this systematic review is to evaluate the effects of external and internal focus of attention on motor performance in healthy older adults. The literature search was conducted in five electronic databases (PsycINFO, PubMed, SPORTDiscus, Scopus, and Web of Science). Eighteen studies that met the inclusion criteria were evaluated. Most of the motor tasks targeting older adults were related to postural control and gait. Over 60% of the included studies reported that the effect of an external focus was superior to that of an internal focus on motor performance in older adults. An external focus generally results in better motor performance than an internal focus among healthy older adults. However, the advantage of an external focus on locomotion may not be as significant as those illustrated in previous attentional focus studies. A challenging cognitive task may allow more automatic motor control than an external focus. Practitioners might provide clear instruction cues guiding performers to divert their attention away from their body and towards the movement effect for better performance, particularly in balancing tasks.

Utilising an internal focus of attention during preparation and an external focus during execution may facilitate motor learning

Research with athletes and coaches has found that attentional focus strategies are more complex than using an internal or external focus exclusively. Recently Becker et al. [2020, March 1. The effects of attentional focus in the preparation and execution of a standing long jump. Psychological Research, 84(2), 285-291] found that switching attentional focus from internal in movement preparation to external during movement execution provided a benefit over internal focus and control conditions. The purpose of this study was to investigate the effects of attentional switching on motor skill acquisition. 79 participants were randomly divided into an internal (INT), external (EXT), or switching group (IES). Individuals performed 80 acquisition trials of a golf chipping task with their prescribed attentional focus during preparation and execution. 24-hours later 10-trial retention and transfer tests were performed. The primary analysis revealed significant improvement during acquisition (p < .001) but no significant differences between attentional focus groups during acquisition, retention, or transfer. A secondary analysis was performed with individuals low in attentional focus adherence removed (<60%). Groups significantly improved during acquisition (p < .001). For retention IES significantly outperformed INT (p < .05). These results suggest that the detrimental effects of an internal focus are only found during skill execution and not movement preparation. It is possible for learners to benefit from both an internal and external focus so long as the cues are provided during the correct phase of skill performance.Highlights Attentional focus is much more complex than using either an internal or external focus of attention. This study investigated the effects of switching attention during skill acquisition from an internal to external focus.A preliminary analysis revealed no significant differences between attentional focus groups of internal, external, or switching. One reason for this finding was the poor adherence to the prescribed focus cue.A secondary analysis where low adherence individuals were removed revealed a significant difference between the switching group and the internal focus group during retention.These finding suggest that the detrimental effects associated with an internal focus of attention are exclusive to using the focus during task execution. It is possible that an internal focus can still facilitate learning so long as an external focus is used during movement execution.

Focus of Attention in Voice Training

OBJECTIVE

The vast majority of motor learning studies investigating focus of attention have found that an external focus of attention (focusing on the effect of a movement) results in enhanced performance and learning, compared to an internal focus of attention (focusing on the body movement itself). The present study attempts to determine if the high incidence of internal focus of attention instruction that has been reported in the realm of athletics is replicated in voice training.

METHODS

Two hundred and seventy-eight singers, who were at least 18 years old and taking voice lessons, were recruited to participate in an anonymous research survey entitled "Instructions given to singers in voice lessons." The main six questions asked singers to report phrases or instructions that their studio voice teachers gave them in regard to posture, breathing and/or support, tone clarity and/or onset of tone, space and/or resonance, articulation, and reducing tension.

RESULTS

Approximately 50.83% of the total responses were classified as inducing an external focus, 39.42% were classified as internal focus, 6.48% used a combination of both internal and external focus, and 3.27% were categorized as miscellaneous.

CONCLUSIONS

The results of this study indicate that voice teachers use both external and internal attentional focus directives in the voice studio. Given the robust body of literature supporting the use of external focus, it is noteworthy that the current study found that external focus is used more often than internal focus in voice training.

Direction of attentional focus in prosthetic training: Current practice and potential for improving motor learning in individuals with lower limb loss

Objective

Adopting an external focus of attention has been shown to benefit motor performance and learning. However, the potential of optimizing attentional focus for improving prosthetic motor skills in lower limb prosthesis (LLP) users has not been examined. In this study, we investigated the frequency and direction of attentional focus embedded in the verbal instructions in a clinical prosthetic training setting.

Methods

Twenty-one adult LLP users (8 female, 13 male; 85% at K3 level; mean age = 50.5) were recruited from prosthetic clinics in the Southern Nevada region. Verbal interactions between LLP users and their prosthetists (mean experience = 10 years, range = 4–21 years) during prosthetic training were recorded. Recordings were analyzed to categorize the direction of attentional focus embedded in the instructional and feedback statements as internal, external, mixed, or unfocused. We also explored whether LLP users’ age, time since amputation, and perceived mobility were associated with the proportion of attentional focus statements they received.

Results

We recorded a total of 20 training sessions, yielding 904 statements of instruction from 338 minutes of training. Overall, one verbal interaction occurred every 22.1 seconds. Among the statements, 64% were internal, 9% external, 3% mixed, and 25% unfocused. Regression analysis revealed that female, older, and higher functioning LLP users were significantly more likely to receive internally-focused instructions (p = 0.006, 0.035, and 0.024, respectively).

Conclusions

Our results demonstrated that verbal instructions and feedback are frequently provided to LLP users during prosthetic training. Most verbal interactions are focused internally on the LLP users’ body movements and not externally on the movement effects.

Impact statement

While more research is needed to explore how motor learning principles may be applied to improve LLP user outcomes, clinicians should consider adopting the best available scientific evidence during treatment. Overreliance on internally-focused instructions as observed in the current study may hinder prosthetic skill learning.

An Examination of the Contextual Interference Effect and the Errorless Learning Model during Motor Learning

The purpose of this study was to investigate the combined effects of random and block practice, with errorless and errorful conditions, on motor learning. One hundred-twenty participants (all male, Mage = 21.19 ± 1.4 years) were randomly assigned to one of eight groups. Participants completed a dart throwing task across the experimental phases. In the retention test, evidence supporting the CI effect was found in the 'errorless' conditions, but not in the 'errorful' conditions. In the transfer tests, the findings indicated that the impact of errorless and errorful conditions on participants' automation levels depends on the structure of practice. Participants in the Random-Errorless group performed better in the transfer tests than those in the Random group and the Random-Errorful group, suggesting greater automation levels following errorless practice.

Visual-motor attention in children with ADHD: The role of automatic and controlled processes

BACKGROUND

there are evidence that children with ADHD exhibit a deficit both in automatic and controlled processes.

AIMS

the present study aimed to examine the visual-motor attention and the influence of cognitive load through a dual task paradigm in children with ADHD compared with typical developing children (TD).

METHODS AND PROCEDURES

113 children with ADHD: 40 with subtype inattentive (ADHD- I group), 16 with subtype hyperactive (ADHD-H group), 57 with subtype combined (ADHD-C group), and 113 TD children (TD group) were recruited. We used a dual-task paradigm in which the primary task was a figure-tracing test whereas the second task was a digit span test. A figure-tracing test was used to evaluate visual motor attention. Based on the length and intersection of the lines, the figures of the primary task were categorized into simple and complex.

OUTCOMES AND RESULTS

the ADHD groups compared to the TD group showed a worse accuracy of performance in both condition with and without cognitive load.

CONCLUSIONS AND IMPLICATIONS

The findings were discussed in light of the relationship between automatic and controlled processes involved in the visual-motor attention.

The Effects of Attentional Focus and Skill Level on the Performance of Golf Putting

The purpose of this study was to examine the distance of varying focus of attention for experienced and novice golfers on a golf putting task. Forty-eight experienced and 48 novice golfers were randomized into four attentional focus conditions: control (no instruction), internal (i.e., focus on the arm movement), external proximal (i.e., focus on the golf club), and external distal (i.e., focus on the target) conditions. Performance outcomes (the perceived level of confidence and number of golf putts made) were recorded. Experienced golfers had better performance outcomes than novice golfers. The external proximal focus was specifically beneficial for novice golfers, while experienced golfers had an advantage in both external focus instructions. The external proximal focus might enable a perception-action process for novice golfers to compare the relationship between action planning and the surrounding environment. In addition, the transition to expertise might result in no difference between both external focus instructions for experienced golfers.

Effects of an expert-modeled attentional focus cue structure on skilled jump rope performance and learning

Instructions that direct attention externally have been shown to enhance motor performance. However, research on skilled performers and on learning effects has produced some distinct findings. Further, many studies have presented an overly simplistic view of attention and learning, such that all-internal focus protocols are contrasted with all-external focus protocols. Contrary to this approach, skilled performers have reported adopting combined focus strategies, revealing the need to test more realistic instructional protocols. The current study provided an experimental test of focus instructions that were modeled after the strategies of elite jump rope athletes. Four groups of skilled jump rope athletes practiced novel skills under various focus instructions. The internal focus (IF) and external focus (EF) groups were given traditional internal and external focus instructions, respectively. The expert modeled (EM) group was given a set of instructions that were based on experts' reported focus strategies. The expert modeled-autonomous (EM-A) group was allowed to choose how they used each of the expert-modeled instructions. All groups completed a baseline assessment, four practice sessions, and a learning assessment. Results of a chi-square test of independence revealed no relationship between group assignment and performance during baseline or practice. There was a significant relationship between group assignment and performance during the learning assessment (p < .05). Specifically, the IF group performed below expected values while the EM group performed better than expected. Findings support previous research showing learning detriments associated with internal focus instructions and also provide new insight into the advantages of using instructional approaches that are modeled after experts' strategies. Implications and suggestions for future research are discussed.

Changes in landing mechanics using augmented feedback: 4-Week training and retention study

CONTEXT

Non-contact ACL injuries are common in female athletes during landing tasks. Post-trial performance-based feedback may be an effective method to reduce landing forces and knee valgus during landing. Information regarding the retention of these changes based on such training is generally lacking for weekly and monthly retention.

OBJECTIVE

To determine the effectiveness of post-trial feedback training to promote and retain changes in vertical ground reaction force (vGRF) and knee to ankle (K:A) ratio during a dual task drop landing in female collegiate athletes.

DESIGN

Repeated measures; SETTING: University campus.

PARTICIPANTS

22 female collegiate athletes.

MATERIALS AND METHODS

Dual task drop landings were performed over 4 successive weeks with immediate post trial feedback on peak vGRF, symmetry, and K:A ratio. K:A ratio was a surrogate measure for knee valgus in drop landing.

RESULTS

Significant decreases in vGRF and increases in K:A ratio were found within training sessions (p = .000). Both variables were retained each week over the 4 weeks.

CONCLUSION

Using a custom portable clinical feedback system may be an effective tool in reducing peak vGRFs and knee abduction angles during a drop landing over a 4-week period in female collegiate athletes.

Attentional Focus and Individuals’ Perceptions: A Systematic Review

Although multiple review studies have supported the superior effects of an external compared with internal focus, these reviews are based on performance outcomes. Currently, the literature lacks knowledge regarding the effects of external/internal foci on individuals’ perceptions, which may provide further explanations for how attentional focus affects performance. Therefore, the present study conducted a systematic review of survey/questionnaire data of participants’ thoughts and emotions from laboratory studies. The authors used ERIC, SPORTDiscus, PsycArticle, CINAHL Plus, Health Source Nursing Academic edition, and PubMed search engines. Literature specific to external/internal focus effects on motor learning or performance were reviewed (N = 37). The results showed that participants generally adhered to the assigned attentional focus instruction and there was a trend that preference may affect the attentional focus effects, but the results were inconsistent regarding if attentional focus cues affected the magnitude of adherence and mental demands. There were substantial differences in methodologies and theoretical issues of measuring these data. Future studies should adopt inferential statistics, choose theoretically relevant questions in a priori manner, or, at minimum, propose a hypothesis for the selected question.

Implicit motor learning in primary school children: A systematic review

The aim of this study was to assess the current state of evidence and methodological quality of studies on implicit and explicit motor learning in both typically developing children and children with developmental disorders. A systematic literature review was conducted on the experimental literature published up to April 2020. A total of 25 studies were included. Studies were evaluated on methodological quality, paradigm used, and level of evidence. The results showed that implicit paradigms are as effective as explicit paradigms in both groups of children. Studies are predominantly experimental in nature involving mostly upper limb aiming tasks. The few studies that were performed outside the lab (n = 5) suggest superior efficacy of the implicit paradigm. Methodological quality varied between studies and was not always of sufficient standard to allow conclusions. In particular, manipulation checks were only performed in 13 studies (52% of all studies), limiting conclusions. Further progress can be made by focussing on improving methodological quality through retention testing by the inclusion of a control group, by the inclusion of a manipulation check, and via assessment of relevant co-variables, such as working memory, age, and motor competence.

The Effects of Biofeedback on Performance and Technique of the Boxing Jab

A growing body of research has addressed the application of movement-based biofeedback techniques for improving sports performers’ gross motor skills. Unlike in previous research, we aimed in this study to quantify the effects of this “external” biofeedback on selected performance and technique variables for the boxing jab among both novices and experts. The technical setup included two inertial measurement units linked wirelessly to a video game system with audio output. The units were configured to provide auditory external biofeedback, based on the peak acceleration of the bag (i.e., biofeedback with an external attentional focus). Sixteen participants (8 novices and 8 experts) performed boxing jabs against the bag in blocked phases of biofeedback. When compared to baseline, the acute effects of externally focused biofeedback on peak bag acceleration were possibly positive in both retention phases for novices (d = 0.29; d = 0.41) and likely positive for experts (d = 0.41; d = 0.30), respectively. The experts’ performance improvements were accompanied by substantive increases in trunk rotation, though this was not true for the novices. Thus, technique improvements can be promoted indirectly via externally focused biofeedback, but only when these actions are within the performers’ motor repertoire. Overall, biofeedback via inertial sensors appears to be a potent technique for modifying human movement patterns in both experts and novices. This low-cost technology could be used to support training across sports, rehabilitation and human-computer interactions.

How to Improve Fine Motor Skill Learning in Dentistry

Introduction

Restorative dental treatment is a complex task involving various procedures which require the development and integration of both theoretical knowledge and fine motor skills. It aims to provide the theoretical background and role of key factors in learning these skills.

Materials and Methods

The following electronic databases were searched to identify relevant articles to our topic: PubMed, Medline, Google Scholar, and Scopus. Generic keywords, that is, factors, fine, performance, and dentistry, and MeSH terms, that is, "learning," "instruction," "patient simulation," "motor skills," "perception," "tactile," "neurophysiology," and "working memory" were used to conduct our comprehensive search. Results and Conclusions. Several techniques are used in performing different restorative procedures in dentistry, that is, root canal preparation, root planning, and minor oral surgery procedures. Mastering these techniques requires a good understanding of the underpinning cognitive, sensory, and neuromuscular processes. Factors including the amount and timing of instructions provided, cognitive abilities, and practice schedule of learning trials may have significant implications on the design of fine motor skill learning exercises.

Effects of Attentional Strategies on Novice Dart Throwing, Quiet Eye Duration and Pupillary Responses

This study examined the effects of focus of attention (FOA) instructions on learning a dart throwing task, quiet eye duration (QED) and pupillary responses. Thirty-six novices (M age = 33.6, SD = 19.7) learned using either (a) internal-focus (arm movement), (b) external-focus (target/dart) or (c) control instructions before completing retention and transfer tests 10 days later. FOA strategies did not significantly benefit dart throwing learning or performance. QED was associated with performance in the transfer task, and pupillary constriction occurred during the QED. The content of FOA instructions may have limited anticipated performance benefits and reduced the FOA influence on QED. Pupillary constriction reflected increased cognitive effort during QED, suggesting an important feature of future precision aiming research.

Individualized feedback to change multiple gait deficits in chronic stroke

Background

Walking deficits in people post-stroke are often multiple and idiosyncratic in nature. Limited patient and therapist resources necessitate prioritization of deficits such that some may be left unaddressed. More efficient delivery of therapy may alleviate this challenge. Here, we look to determine the utility of a novel principal component-based visual feedback system that targets multiple, patient-specific features of gait in people post-stroke.

Methods

Ten individuals with stroke received two sessions of visual feedback to attain a walking goal. This goal consisted of bilateral knee and hip joint angles of a typical ‘healthy’ walking pattern. The feedback system uses principal component analysis (PCA) to algorithmically weight each of the input features so that participants received one stream of performance feedback. In the first session, participants had to explore different patterns to achieve the goal, and in the second session they were informed of the goal walking pattern. Ten healthy, age-matched individuals received the same paradigm, but with a hemiparetic goal (i.e. to produce the pattern of an exemplar stroke participant). This was to distinguish the extent to which performance limitations in stroke were due neurological injury or the PCA based visual feedback itself.

Results

Principal component-based visual feedback can differentially bias multiple features of walking toward a prescribed goal. On average, individuals with stroke typically improved performance via increased paretic knee and hip flexion, and did not perform better with explicit instruction. In contrast, healthy people performed better (i.e. could produce the desired exemplar stroke pattern) in both sessions, and were best with explicit instruction. Importantly, the feedback for stroke participants accommodated a heterogeneous set of walking deficits by individually weighting each feature based on baseline walking.

Conclusions

People with and without stroke are able to use this novel visual feedback to train multiple, specific features of gait. Important for stroke, the PCA feedback allowed for targeting of patient-specific deficits. This feedback is flexible to any feature of walking in any plane of movement, thus providing a potential tool for therapists to simultaneously target multiple aberrant features of gait.

Comparing the Impact of an Implicit Learning Approach With Standard Care on Recovery of Mobility Following Stroke: Protocol for a Pilot Cluster Randomized Controlled Trial

BACKGROUND

Although implicit and explicit learning approaches have been well investigated in healthy populations, there is less evidence regarding the relative benefits of each approach in clinical practice. Studies in stroke typically investigate single elements of an implicit learning approach (ILA; eg, reduced quantity feedback or an external focus of attention) within controlled environments. These studies predominantly evaluate performance, with few measuring this over time (ie, learning). The relevance and transferability of current research evidence into stroke rehabilitation is therefore limited.

OBJECTIVE

The objective of this study was to compare the ILA with standard care in the acute phase following stroke, to generate data and insights to inform the design of a definitive trial, and to understand patient and therapist perceptions of the ILA.

METHODS

This is a multicenter, assessor-blind, cluster randomized controlled pilot trial with nested qualitative evaluation. Stroke units (clusters) will be randomized to either ILA (intervention) or standard care (control) arms. Therapy teams at the intervention sites will be trained in the ILA and provided with an intervention manual. Those at the control sites will have minimal input from the research team, other than for data collection. Consent will be provided at the individual participant level. Once enrolled, participants will receive rehabilitation that focuses on lower limb recovery, using the designated approach. Measures will be taken at baseline, every 2 weeks until the point of discharge from hospital, and at 3 months post stroke onset. Measures include the Fugl Meyer Assessment (motor leg subsection), modified Rivermead Mobility Index, Swedish Postural Adjustment in Stroke Scale, and achievement of mobility milestones. Fidelity of the treatment approach will be monitored using observational video analysis. Focus groups and interviews will be used to gain insight into the perceptions of trial participants and clinical teams.

RESULTS

The first site opened to recruitment in February 2019. The opening of a further 5 sites will be staggered throughout 2019. Results are expected in early 2021.

CONCLUSIONS

The findings from this mixed methods pilot study will be used to inform the design of a definitive study, comparing the ILA with standard care in acute stroke rehabilitation.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03792126; https://clinicaltrials.gov/ct2/show/NCT03792126.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/14222.

The Inter-Regional Connectivity Within the Default Mode Network During the Attentional Processes of Internal Focus and External Focus: An fMRI Study of Continuous Finger Force Feedback

Sustained attention involves two distinct processes, i.e., external focus and internal focus. Some recent neuroimaging studies employed the instruction of experimenters or the self-report from participants to generate the two attentional processes, and observed that the default mode network (DMN) was also responding to the external focus. These observations challenged the general view that the DMN accounts for the internally directed cognition, e.g., unfocused mind wandering, task independent-thoughts and internally focused events. Notably, the instruction or self-report may not effectively ensure the participants engage in the external focus/internal focus, and thus, the functional significance of the DMN for the externally focused process remains to be verified. In the present study, a new task paradigm, i.e., real/sham continuous feedback of finger force, was employed to generate the attentional process of external focus/internal focus, and the functional connectivity among the node regions of the DMN was further investigated in the two processes respectively. We found that two regions of the DMN, posterior cingulate cortex and left inferior parietal cortex/angular gyrus showed stronger inter-regional connectivity in the externally focused process than it in the internally focused process. Intriguingly, this functional connectivity was closely related to the behavioral performance in the process of external focus. These findings implicated that the functional significance of the DMN in sustained attention was more than responding to the internally directed cognition, and the task paradigm of continuous finger force feedback could benefit for the future studies on the externally focused/internally focused process of sustained attention.

External focus of attention concurrently elicits optimal performance of suprapostural pole-holding task and postural stability in children with developmental coordination disorder

The aim of this study was to determine the effects of different attentional focus conditions (external focus (EF) vs. internal focus (IF) vs. no focus (NF)) on the performance of a pole-holding task and postural stability in children with developmental coordination disorder (DCD) and typically developing children (TDC), while addressing previous study limitations. A total of 186 participants were enrolled in the analysis comprising 91 children with DCD (28 in the EF, 32 in the IF, and 31 in the NF condition) and 95 TDC (31 in the EF, 33 in the IF, and 31 in the NF condition). Participants were required to hold a pole with their hands still and parallel to the floor while focusing on pole movement (EF), focusing on hands (IF), or without focus instructions (NF), while pole movements and postural sway were recorded. Results showed that pole movements were significantly smaller during the EF condition (p < 0.05) compared with IF and NF conditions for both the DCD and TDC groups. In addition, postural sway was significantly lower during the EF condition compared with IF and NF conditions (p < 0.05). This study verified that the EF condition can not only facilitate better performance in holding a pole horizontal and immobile, but also concurrently promote greater postural stability than both IF and NF conditions for children with DCD and TDC.

Expert and Novice Performers Respond Differently to Attentional Focus Cues for Speed Jump Roping

Directing attention to an external focus has been shown to facilitate motor performance. For expert performers, however, results have been mixed. Additionally, little is currently known about how focus cues affect the performance of complex continuous whole-body coordination tasks involving object manipulation such as jump roping. The purpose of this study was to examine the effects of attentional focus cues on single-rope speed jumping by experts and novices. The cues directed attention toward the upper (UP) or lower (LB) body and either internally (IN) or externally (EX). Participants (N = 30) completed bouts of speed jumping during a baseline trial and under experimental conditions (UPIN, UPEX, LBIN, LBEX). Jumps and errors were recorded for each trial. Number of jumps (NJ) and errors (NE) were analyzed using separate Friedman's Tests comparing for each group to compare trials, with Wilcoxon Signed-Rank Tests for post hoc comparisons. Cumulative number of jumps (CNJ) and errors (CNE) for each condition were compared using separate Friedman's Tests with Wilcoxon Signed-Rank Tests for post hoc comparisons. For experts, baseline NJ was significantly higher than NJ for each trial under the UPIN, UPEX, and LBIN conditions. No differences between baseline NE and any trials were detected. Additionally, no differences were detected between conditions for NJ or NE. For novices, baseline NJ and NE were significantly higher and lower, respectively, compared to Trial 1 under the LBEX condition. Both the UPIN and UPEX conditions produced higher CNJ and lower CNE than the LBIN and LBEX conditions, respectively. Results showed that experts and novices responded in distinctly different patterns to the four conditions. Experts showed degraded performance under the UPIN, UPEX, and LBIN conditions whereas novices only showed temporarily degraded performance under the LBEX condition. These findings may reflect differences in mastery of whole-body coordination and are partially consistent with the Constrained Action Hypothesis (CAH) despite not supporting specific predictions related to the benefit of external focus cues.

Does implicit motor learning lead to greater automatization of motor skills compared to explicit motor learning? A systematic review

Background

Implicit motor learning is considered to be particularly effective for learning sports-related motor skills. It should foster movement automaticity and thereby facilitate performance in multitasking and high-pressure environments. To scrutinize this hypothesis, we systematically reviewed all studies that compared the degree of automatization achieved (as indicated by dual-task performance) after implicit compared to explicit interventions for sports-related motor tasks.

Methods

For this systematic review (CRD42016038249) conventional (MEDLINE, CENTRAL, Embase, PsycINFO, SportDiscus, Web of Science) and grey literature were searched. Two reviewers independently screened reports, extracted data, and performed risk of bias assessment. Implicit interventions of interest were analogy-, errorless-, dual-task-, and external focus learning. Data analysis involved descriptive synthesis of group comparisons on absolute motor dual-task (DT) performance, and motor DT performance relative to single-task motor performance (motor DTCs).

Results

Of the 4125 reports identified, we included 25 controlled trials that described 39 implicit-explicit group comparisons. Risk of bias was unclear across trials. Most comparisons did not show group differences. Some comparisons showed superior absolute motor DT performance (N = 2), superior motor DTCs (N = 4), or both (N = 3) for the implicit compared to the explicit group. The explicit group showed superior absolute motor DT performance in two comparisons.

Conclusions

Most comparisons did not show group differences in automaticity. The remaining comparisons leaned more toward a greater degree of movement automaticity after implicit learning than explicit learning. However, due to an overall unclear risk of bias the strength of the evidence is level 3. Motor learning-specific guidelines for design and especially reporting are warranted to further strengthen the evidence and facilitate low-risk-of-bias trials.

Are the effects of internal focus instructions different from external focus instructions given during balance training in stroke patients? A double-blind randomized controlled trial

Objective:

This study aimed to assess if external focus instructions result in greater improvements in motor skill and automaticity compared to internal focus instructions in stroke patients.

Design:

Double-blind randomized controlled trial.

Setting:

Inpatient stroke rehabilitation unit.

Subjects:

A total of 63 stroke patients (Meanage = 59.6 ± 10.7 years; Meandays since stroke = 28.5 ± 16.6; MedianFunctional Ambulation Categories = 4).

Interventions:

Patients were randomly assigned to an internal ( N = 31) or external ( N = 32) focus instruction group. Both groups practiced a balance board stabilization task, three times per week, for three weeks. Balance performance was assessed at baseline, and after one and three weeks of practice.

Main measures:

Primary outcome was the threshold stiffness (Nm/rad) at which patients could stay balanced. Secondary outcomes were patients’ sway (root-mean-square error in degrees) at the baseline threshold stiffness under single- and dual-task conditions, and their performance on the Timed Up and Go Test and Utrecht Scale for Evaluation of Rehabilitation.

Results:

Both groups achieved similar improvements in threshold stiffness (∆= 27.1 ± 21.1 Nm/rad), and single- (∆= 1.8 ± 2.3° root-mean-square error) and dual-task sway (∆= 1.7 ± 2.1° root-mean-square error) after three weeks of practice. No differences were found in improvements in clinical tests of balance and mobility. Patients with comparatively good balance and sensory function, and low attention capacity showed greatest improvements with external focus instructions.

Conclusion:

External focus instructions did not result in greater improvement in balance skill in stroke patients compared to internal focus instructions. Results suggest that tailoring instructions to the individual stroke patient may result in optimal improvements in motor skill.

Motor learning and movement automatization in typically developing children: The role of instructions with an external or internal focus of attention

The aim of the current study was to examine the effects of an external focus of attention (i.e., on the movement outcome) versus an internal focus of attention (i.e., on the movement itself) on motor learning in typically developing children. We examined both immediate motor performance (i.e., practice effect, when focus instructions are given) as well as motor performance after one week (i.e., learning effect). In addition, we examined if an external and an internal focus of attention differently affected movement automatization, as measured using a dual-task paradigm. Finally, we explored whether the effect of attentional focus instructions on motor learning was influenced by children's working memory capacity. Participants were 8-12 year old (N = 162) typically developing children. Participants practiced a new motor task (i.e., 'Slingerball throwing task'). Results showed that an external focus of attention led to higher throwing accuracy during practice, but this beneficial effect did not extent to the retention test one week later. Furthermore, movement automatization did not differ after external or internal focus of attention instructions, and working memory capacity did not predict motor learning in children in either of the instruction conditions. This is the first study to show that the beneficial effects of an external focus of attention on discrete motor tasks found in previous studies with a child population seem to be short lived and decline after a one-week interval.

Individual Differences Influencing Immediate Effects of Internal and External Focus Instructions on Children's Motor Performance

PURPOSE

A large pool of evidence supports the beneficial effect of an external focus of attention on motor skill performance in adults. In children, this effect has been studied less and results are inconclusive. Importantly, individual differences are often not taken into account. We investigated the role of working memory, conscious motor control, and task-specific focus preferences on performance with an internal and external focus of attention in children.

METHODS

Twenty-five children practiced a golf putting task in both an internal focus condition and external focus condition. Performance was defined as the average distance toward the hole in 3 blocks of 10 trials. Task-specific focus preference was determined by asking how much effort it took to apply the instruction in each condition. In addition, working memory capacity and conscious motor control were assessed.

RESULTS

Children improved performance in both the internal focus condition and external focus condition (ŋ_p² = .47), with no difference between conditions (ŋ_p² = .01). Task-specific focus preference was the only factor moderately related to the difference between performance with an internal focus and performance with an external focus (r = .56), indicating better performance for the preferred instruction in Block 3.

CONCLUSION

Children can benefit from instruction with both an internal and external focus of attention to improve short-term motor performance. Individual, task-specific focus preference influenced the effect of the instructions, with children performing better with their preferred focus. The results highlight that individual differences are a key factor in the effectiveness in children's motor performance. The precise mechanisms underpinning this effect warrant further research.

Over-focused? The relation between patients' inclination for conscious control and single- and dual-task motor performance after stroke

BACKGROUND

Many stroke patients are inclined to consciously control their movements. This is thought to negatively affect patients' motor performance, as it disrupts movement automaticity. However, it has also been argued that conscious control may sometimes benefit motor performance, depending on the task or patientś motor or cognitive capacity.

AIM

To assess whether stroke patients' inclination for conscious control is associated with motor performance, and explore whether the putative association differs as a function of task (single- vs dual) or patientś motor and cognitive capacity.

METHODS

Univariate and multivariate linear regression analysis were used to assess associations between patients' disposition to conscious control (i.e., Conscious Motor Processing subscale of Movement-Specific Reinvestment Scale; MSRS-CMP) and single-task (Timed-up-and-go test; TuG) and motor dual-task costs (TuG while tone counting; motor DTC%). We determined whether these associations were influenced by patients' walking speed (i.e., 10-m-walk test) and cognitive capacity (i.e., working memory, attention, executive function).

RESULTS

Seventy-eight clinical stroke patients (<6 months post-stroke) participated. Patients' conscious control inclination was not associated with single-task TuG performance. However, patients with a strong inclination for conscious control showed higher motor DTC%. These associations were irrespective of patients' motor and cognitive abilities.

CONCLUSION

Patients' disposition for conscious control was not associated with single task motor performance, but was associated with higher motor dual task costs, regardless of patients' motor or cognitive abilities.

CLINICAL RELEVANCE

Therapists should be aware that patients' conscious control inclination can influence their dual-task performance while moving. Longitudinal studies are required to test whether reducing patients' disposition for conscious control would improve dual-tasking post-stroke.

External Versus Two Different Internal Foci of Attention in Long-Distance Throwing

The present study examined the influence of attentional focus on performance during a long-distance throwing task. Twelve participants executed three maximum-effort, long-distance baseball throwing attempts in three focus conditions: internal focus on wrist flexion (wrist internal focus), internal focus on the separation between pelvis and upper torso orientations (torso internal focus), and external focus on the ball path (external focus). Compared with the external focus and torso internal focus conditions, performance was poorer in the wrist internal focus condition. Performances were not different in the torso internal and external focus conditions. In addition, attentional focus affected the release angle of the ball but not its initial velocity. Our results reveal that the body part targeted for internal focus of attention and the forcefulness of the motor activity can be as important to motor performance as whether the attention is internal or external.

Investigating the Constrained Action Hypothesis: A Movement Coordination and Coordination Variability Approach

The purpose of this study was to examine the effects of focus of attention cues on movement coordination and coordination variability in the lower extremity. Twenty participants performed the standing long jump under both internal and external focus of attention conditions. A modified vector coding technique was used to evaluate the influence of attentional focus cues on lower extremity coordination patterns and coordination variability during the jumps. Participants jumped significantly further under an external focus of attention condition compared with an internal focus of attention condition (p = .035, effect size = .29). Focus of attention also influenced coordination between the ankle and knee, F(6, 19) = 2.87, p = .012, effect size = .388, with participants primarily using their knees under the internal focus of attention, and using both their ankles and knees under the external focus of attention. Attentional focus cues did not influence ankle-knee, F(1, 19) = 0.02, p = .98, effect size = .02, or hip-knee, F(1, 19) = 5.00, p = .49, effect size = .16, coordination variability. Results suggest that while attentional focus may not directly influence movement coordination condition, there is still a change in movement strategy resulting in greater jump distances following an external focus of attention.

Working Memory Capacity Limits Motor Learning When Implementing Multiple Instructions

Although it is generally accepted that certain practice conditions can place large demands on working memory (WM) when performing and learning a motor skill, the influence that WM capacity has on the acquisition of motor skills remains unsubstantiated. This study examined the role of WM capacity in a motor skill practice context that promoted WM involvement through the provision of explicit instructions. A cohort of 90 children aged 8 to 10 years were assessed on measures of WM capacity and attention. Children who scored in the lowest and highest thirds on the WM tasks were allocated to lower WM capacity (n = 24) and higher WM capacity (n = 24) groups, respectively. The remaining 42 participants did not participate in the motor task. The motor task required children to practice basketball shooting for 240 trials in blocks of 20 shots, with pre- and post-tests occurring before and after the intervention. A retention test was administered 1 week after the post-test. Prior to every practice block, children were provided with five explicit instructions that were specific to the technique of shooting a basketball. Results revealed that the higher WM capacity group displayed consistent improvements from pre- to post-test and through to the retention test, while the opposite effect occurred in the lower WM capacity group. This implies that the explicit instructions had a negative influence on learning by the lower WM capacity children. Results are discussed in relation to strategy selection for dealing with instructions and the role of attention control.

Experience level influences the effect of attentional focus on sprint performance

Two experiments evaluated the influence of attentional focus on 10-meter sprint time and start kinetics in a group of collegiate soccer players and highly experienced sprinters. In Experiment 1, the collegiate soccer players were asked to perform 10-meter sprints under an external focus condition, an internal focus condition and a control condition. For the 10-meter sprint time, the results showed that both the external focus and control conditions resulted in significantly faster sprint times than the internal focus condition. There were no significant differences observed between the external focus and control conditions. There were also no significant differences observed across any of the conditions for a select set of kinetic variables. In Experiment 2, the highly experienced sprinters performed the same 10-meter sprint task using the same instructional conditions as in Experiment 1. For the 10-meter sprint time and kinetic variables, there were no significant differences observed across any of the conditions. These results provide new evidence that experience level mediates the influence of attentional focus on sprint performance.

Is Implicit Motor Learning Preserved after Stroke? A Systematic Review with Meta-Analysis

Many stroke patients experience difficulty with performing dual-tasks. A promising intervention to target this issue is implicit motor learning, as it should enhance patients’ automaticity of movement. Yet, although it is often thought that implicit motor learning is preserved post-stroke, evidence for this claim has not been systematically analysed yet. Therefore, we systematically reviewed whether implicit motor learning is preserved post-stroke, and whether patients benefit more from implicit than from explicit motor learning. We comprehensively searched conventional (MEDLINE, Cochrane, Embase, PEDro, PsycINFO) and grey literature databases (BIOSIS, Web of Science, OpenGrey, British Library, trial registries) for relevant reports. Two independent reviewers screened reports, extracted data, and performed a risk of bias assessment. Overall, we included 20 out of the 2177 identified reports that allow for a succinct evaluation of implicit motor learning. Of these, only 1 study investigated learning on a relatively complex, whole-body (balance board) task. All 19 other studies concerned variants of the serial-reaction time paradigm, with most of these focusing on learning with the unaffected hand (N = 13) rather than the affected hand or both hands (both: N = 4). Four of the 20 studies compared explicit and implicit motor learning post-stroke. Meta-analyses suggest that patients with stroke can learn implicitly with their unaffected side (mean difference (MD) = 69 ms, 95% CI[45.1, 92.9], p < .00001), but not with their affected side (standardized MD = -.11, 95% CI[-.45, .25], p = .56). Finally, implicit motor learning seemed equally effective as explicit motor learning post-stroke (SMD = -.54, 95% CI[-1.37, .29], p = .20). However, overall, the high risk of bias, small samples, and limited clinical relevance of most studies make it impossible to draw reliable conclusions regarding the effect of implicit motor learning strategies post-stroke. High quality studies with larger samples are warranted to test implicit motor learning in clinically relevant contexts.

Stay Focused! The Effects of Internal and External Focus of Attention on Movement Automaticity in Patients with Stroke

Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients’ automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution). Thirty-nine individuals with chronic, unilateral stroke performed a one-leg-stepping task with both legs in single- and dual-task conditions. Attentional focus was manipulated with instructions. Motor performance (movement speed), movement automaticity (fluency of movement), and dual-task performance (dual-task costs) were assessed. The effects of focus on movement speed, single- and dual-task movement fluency, and dual-task costs were analysed with generalized estimating equations. Results showed that, overall, single-task performance was unaffected by focus (p = .341). Regarding movement fluency, no main effects of focus were found in single- or dual-task conditions (p’s ≥ .13). However, focus by leg interactions suggested that an external focus reduced movement fluency of the paretic leg compared to an internal focus (single-task conditions: p = .068; dual-task conditions: p = .084). An external focus also tended to result in inferior dual-task performance (β = -2.38, p = .065). Finally, a near-significant interaction (β = 2.36, p = .055) suggested that dual-task performance was more constrained by patients’ attentional capacity in external focus conditions. We conclude that, compared to an internal focus, an external focus did not result in more automated movements in chronic stroke patients. Contrary to expectations, trends were found for enhanced automaticity with an internal focus. These findings might be due to patients’ strong preference to use an internal focus in daily life. Future work needs to establish the more permanent effects of learning with different attentional foci on re-automating motor control after stroke.

An occlusion paradigm to assess the importance of the timing of the quiet eye fixation

The aim of the study was to explore the significance of the 'timing' of the quiet eye (QE), and the relative importance of late (online control) or early (pre-programming) visual information for accuracy. Twenty-seven skilled golfers completed a putting task using an occlusion paradigm with three conditions: early (prior to backswing), late (during putter stroke), and no (control) occlusion of vision. Performance, QE, and kinematic variables relating to the swing were measured. Results revealed that providing only early visual information (occluding late visual information) had a significant detrimental effect on performance and kinematic measures, compared to the control condition (no occlusion), despite QE durations being maintained. Conversely, providing only late visual information (occluding early visual information) was not significantly detrimental to performance or kinematics, with results similar to those in the control condition. These findings imply that the visual information extracted during movement execution - the late proportion of the QE - is critical when golf putting. The results challenge the predominant view that the QE serves only a pre-programming function. We propose that the different proportions of the QE (before and during movement) may serve different functions in supporting accuracy in golf putting.

We Are Able, We Intend, We Act—But We Do Not Succeed: A Theoretical Framework for a Better Understanding of Paradoxical Performance in Sports

Paradoxical performance can be described simply as a sudden decrease in a top athlete’s performance despite the athlete’s having striven for superior performance, such as the lost-skill syndrome in trampolining or “the yips” in golf. There is a growing amount of research on these phenomena, which resemble movement disorders. What appears to be missing, however, is a clear phenomenology of the affected movement characteristics leading to a classification of the underlying cause. This understanding may enable specific diagnostic methods and appropriate interventions. We first review the different phenomena, providing an overview of their characteristics and their occurrence in sports and describing the affected sports and movements. We then analyze explanations for the yips, the most prominent phenomenon, and review the methodological approaches for diagnosing and treating it. Finally, we present and elaborate an action theoretical approach for diagnosing paradoxical performance and applying appropriate interventions.

Neural basis of postural focus effect on concurrent postural and motor tasks: phase-locked electroencephalogram responses

Dual-task performance is strongly affected by the direction of attentional focus. This study investigated neural control of a postural-suprapostural procedure when postural focus strategy varied. Twelve adults concurrently conducted force-matching and maintained stabilometer stance with visual feedback on ankle movement (visual internal focus, VIF) and on stabilometer movement (visual external focus, VEF). Force-matching error, dynamics of ankle and stabilometer movements, and event-related potentials (ERPs) were registered. Postural control with VEF caused superior force-matching performance, more complex ankle movement, and stronger kinematic coupling between the ankle and stabilometer movements than postural control with VIF. The postural focus strategy also altered ERP temporal-spatial patterns. Postural control with VEF resulted in later N1 with less negativity around the bilateral fronto-central and contralateral sensorimotor areas, earlier P2 deflection with more positivity around the bilateral fronto-central and ipsilateral temporal areas, and late movement-related potential commencing in the left frontal-central area, as compared with postural control with VIF. The time-frequency distribution of the ERP principal component revealed phase-locked neural oscillations in the delta (1-4Hz), theta (4-7Hz), and beta (13-35Hz) rhythms. The delta and theta rhythms were more pronounced prior to the timing of P2 positive deflection, and beta rebound was greater after the completion of force-matching in VEF condition than VIF condition. This study is the first to reveal the neural correlation of postural focusing effect on a postural-suprapostural task. Postural control with VEF takes advantage of efficient task-switching to facilitate autonomous postural response, in agreement with the "constrained-action" hypothesis.

Novel methods of instruction in ACL injury prevention programs, a systematic review

Anterior cruciate ligament (ACL) injury prevention programs have been successful in the short term. Motor learning strategies with an internal focus (IF) to body movements have traditionally been utilized, but may be less suitable than an external focus (EF) for the acquisition and control of complex motor skills required for sport. To investigate the available literature and provide an overview of the effect of IF and EF instructions on jump landing technique. Systematic searches were conducted in PubMed (1966 to May 2014), CINAHL (1981 to May 2014) and PsycInfo (1989 to May 2014). A priori defined inclusion criteria were: (i) full text; (ii) published in English, German or Dutch; (iii) healthy adult subjects (mean age ≥18 years); (iv) jump and landing performance tested and (v) study used comparison between an EF and IF. Performance (jump height and distance) and technique (kinematics and kinetics) were the primary outcome variables of interest. Nine papers were included. Significant better motor performance and movement technique was found with an EF compared to an IF. Considering the beneficial results in the included studies when utilizing an EF, it is suggested to implement these strategies into ACL injury prevention programs.