A closed-loop theory of motor learning

[Innovative noninvasive gait-synchronized vibrotactile feedback system : "I can feel myself walking again"]

Despite intensive research and development of systems for restoration of sensory information, these have so far only been the subject of study protocols. A new noninvasive feedback system translates pressure loads on the forefoot and hindfoot into gait-synchronized vibrotactile stimulation of a defined skin area. To increase the authenticity, this treatment can be supplemented by a surgical procedure. Targeted sensory reinnervation (TSR) describes a microsurgical procedure in which a defined skin area on the amputated stump of the residual limb is first denervated and then reinnervated by a specific, transposed sensory nerve harvested from the amputated part of the limb. This creates a sensory interface at the residual stump. This article presents the clinical and orthopedic technical treatment pathway with this innovative vibrotactile feedback system and explains in detail the surgical procedure of TSR after amputation of the lower limb.

The multisensory nature of human action imagery

Imagination can appeal to all our senses and may, therefore, manifest in very different qualities (e.g., visual, tactile, proprioceptive, or kinesthetic). One line of research addresses action imagery that refers to a process by which people imagine the execution of an action without actual body movements. In action imagery, visual and kinesthetic aspects of the imagined action are particularly important. However, other sensory modalities may also play a role. The purpose of the paper will be to address issues that include: (i) the creation of an action image, (ii) how the brain generates images of movements and actions, (iii) the richness and vividness of action images. We will further address possible causes that determine the sensory impression of an action image, like task specificity, instruction and experience. In the end, we will outline open questions and future directions.

A qualitative approach to explore the cognitive processes used by members of an adult learn-to-cycle program

Introduction

Attaining movement proficiency under various constraints is well-researched; of particular interest here is how conscious processing and self-consciousness influence learning and performance. Current research relevant to these variables e.g., reinvestment, tends to utilize quantitative methods and thus overlooks a potentially rich source of understanding. Therefore, the purpose of this study was to apply a qualitative approach to explore the cognitive processes and self-consciousness within a less practiced population of adults participating in a non-competitive leisure activity.

Methods

To achieve this, eleven semi-structured interviews were conducted with adult women learning or relearning to ride a bicycle.

Results

Using thematic analysis, two distinct themes were evident and corroborated those illustrated in scales such as the movement-specific reinvestment scale. These themes included Conscious Processing, Recalling Experiences and Movement Analysis, in addition to Style of Movement, and Self-Consciousness. Anxiety also emerged as an additional and relevant theme to learning a new complex movement skill.

Discussion

The findings indicated that participating women attuned to their movements to the extent that there was a conscious attempt to control their movements, but less so regarding movements being altered by self-awareness. Whilst further research is required, qualitative methods provide a promising basis for exploring the cognitive process involved with the conscious process involved in learning.

Fun with electricity: A novel ballistics gelatin model with LED tracking for ultrasound needle guidance

Background

Use of ultrasound (US) for procedural needle guidance can improve success rates, safety, and accuracy. Often, training is performed on task trainers, which can be prohibitively expensive. Determining undesired needle placement is difficult when the needle is poorly visualized with US. Currently available simulation phantoms cannot provide real-time feedback on the location of needle placement.

Objectives

The primary objective was to develop and determine feasibility of a low-cost simulation phantom with an internal circuit and LED light system to determine when a needle contacts internal structures. We also aimed to determine whether its use was associated with increased comfort level.

Methods

Emergency medicine (EM) residents (PGY-1 to PGY-3) performed in-plane and out-of-plane US needle guidance using homemade phantoms. Comfort levels were assessed by pre- and post intervention survey. Outcomes were measured on Likert scale (minimum = 1, maximum = 5). The primary outcome was change in confidence markers before and after the simulation task. Secondary outcomes were survey results of comparisons of these models to prior training experiences on simulators and humans.

Results

All EM residents (30) in our program were invited to participate. Twenty participants enrolled and completed the study. In the primary outcome, median comfort with out-of-plane and in-plane guidance increased after using the model but was more pronounced for out-of-plane guidance. On a posttest survey, residents rated the models overall very similar to prior experience on simulators (median 5/5 [IQR 4.0-5.0]) and moderately similar to humans (median 3/5 [IQR 3.0-4.0]).

Conclusions

We created a low-cost ballistic gelatin phantom with an internal electric needle guidance system. Use of the phantom for training was associated with increased learner comfort with the procedure. Learners rated the characteristics of the phantom as similar to higher-cost commercial equipment and humans.

Acute Effect of Video Feedback on Self-Regulation and Proprioceptive Control of Standing Back Tuck Somersault in the Absence of Vision

The purpose of this study was to assess the immediate effect of video feedback on the regulation and control of the standing back tuck somersault in the absence of vision. Two groups of male parkour athletes performed the standing back tuck somersault under both open and closed eyes conditions. The first group received video feedback, while the second group received verbal feedback. Concurrent analysis, including kinetic data from a force plate (Kistler Quattro-Jump) and kinematic data in two-dimensional by Kinovea freeware, was employed for motion and technical performance analysis. The results indicate that the loss of vision during the standing back tuck somersault affected only the take-off and ungrouping angle, as well as the vertical velocity and displacement. These effects were consistent regardless of the type of feedback provided (i.e., video feedback or verbal feedback). Furthermore, a significant Vision × Feedback interaction was observed at the level of technical performance. This suggests that the use of video feedback enabled the parkour athletes to maintain a high level of technical performance both with and without vision (i.e., 13.56 vs. 13.00 points, respectively, p > .05 and d = 2.233). However, the verbal feedback group technical performance declined significantly under the no-vision condition compared with the vision condition (13.14 vs. 10.25 points, respectively, with and without vision, p < .001 and d = 2.382). We concluded that when the movement is proprioceptively controlled (i.e., without vision), the video feedback enables the athletes to globally assess the technical deficiencies arising from the lack of vision and to correct them. These findings are discussed based on parkour athletes' ability to evaluate the kinematic parameters of the movement.

Temporal samples of visual information guides skilled interception

This study investigated whether performance of an interceptive skill requires an intact visual-perception-action cycle. Eleven skilled male Australian rules football athletes (Mage = 17.54, SD = 0.15) were recruited from an elite developmental pathway squad for a within-subject study. Participants were required to kick a ball directly at a goal from a 20-meter distance while wearing a pair of stroboscopic glasses. The glasses were used to create four vision conditions. Condition one kept intact the visual-perception-action cycle with uninterrupted vision of the motor skill. Three other conditions included stroboscopic vision that presented temporal samples of vision, which interrupted the perception-action cycle through progressive increases to intermittent vision occlusion of the motor skill. Goal kick error of ball position relative to a central target line within the goal and number of successful goals kicked were measured. Written report of internal and external focus of attention was also measured after each vision condition. Generalized estimating equation analysis did not reveal a significant decrement in kick target error, nor accuracy of goals scored, across normal to stroboscopic vision conditions. Performance was maintained despite a shift in attention focus from external to internal across normal to stroboscopic vision conditions. These findings have theoretical and practical implications for the visual regulation of skilled interceptive actions.

Music performance as knowledge acquisition: a review and preliminary conceptual framework

To what extent does playing a musical instrument contribute to an individual's construction of knowledge? This paper aims to address this question by examining music performance from an embodied perspective and offering a narrative-style review of the main literature on the topic. Drawing from both older theoretical frameworks on motor learning and more recent theories on sensorimotor coupling and integration, this paper seeks to challenge and juxtapose established ideas with contemporary views inspired by recent work on embodied cognitive science. By doing so we advocate a centripetal approach to music performance, contrasting the prevalent centrifugal perspective: the sounds produced during performance not only originate from bodily action (centrifugal), but also cyclically return to it (centripetal). This perspective suggests that playing music involves a dynamic integration of both external and internal factors, transcending mere output-oriented actions and revealing music performance as a form of knowledge acquisition based on real-time sensorimotor experience.

Unpacking the black box of voice therapy: A clinical application and revision of the Motor Learning Classification Framework (MLCF)

PURPOSE

Voice therapy is a complex behavioural intervention. Understanding its components is integral for continued advancement of voice therapy research, translation of evidence into the clinical setting and improved client care. The Motor Learning Classification Framework (MLCF) offers an excellent opportunity for increasing such knowledge, specifically in relation to identifying variables that affect motor learning (ML), an important mechanism hypothesised to bring about voice change during voice therapy. The MLCF has shown promising results in identifying speech-language pathologists' (SLPs) use of ML variables during experimentally controlled voice therapy contexts. The purpose of this study was to test the feasibility of applying the framework in the clinical context of everyday voice therapy practice.

METHOD

Data consisted of two video-recorded voice therapy sessions representing usual voice therapy care. Classification of ML variables used by SLPs during the recorded sessions was attempted based on the MLCF.

RESULT

Several problematic features of the framework were identified. Based on deliberations between the authors of the current paper, the MLCF was revised using an iterative process. This resulted in the construction of an updated version of the framework (MLCF-V2). The MLCF-V2 organises ML strategies into two broad categories: directly observable behaviours and learning processes. The framework incorporates greater consideration of theory and empirical evidence supporting motivational, attentional focus and subjective error estimation influences on ML. Several examples of each ML variable are included as well as an attempt to provide clearer classification instruction.

CONCLUSION

It is anticipated that the MLCF-V2 will provide a more useful and reliable classification for use in future investigations of SLPs' use of ML variables during usual voice therapy practice.

[Multiple factors contributing to dysphagia : Extended tasks for the interprofessional team in the intensive care unit]

A stay in the intensive care unit (ICU) can be associated with complications and lead to secondary problems, known as post intensive care syndrome (PICS). They can prolong inpatient stays, increase ICU mortality and lead to long-term problems. One secondarily acquired problem in intensive care is dysphagia. This article highlights various influencing factors on dysphagia. Some require an extended interprofessional treatment concept that goes beyond strictly speech and swallowing therapist treatment.

Mutual interference between memory encoding and motor skills: the influence of motor expertise

In cognitive-motor dual-task situations, the extent of performance decrements is influenced by the attentional requirements of each task. Well-learned motor skills should be automatized, leading to less interference. This study presents two studies combining an episodic memory encoding task with well-practiced motor tasks in athletes. Study 1 asked 40 rowers (early teenagers to middle adulthood) to row on ergometers at slow or fast speeds. In study 2, Taekwondo athletes (n = 37) of different skill levels performed a well-practiced sequence of martial arts movements. Performing the motor task during encoding led to pronounced performance reductions in memory in both studies, with costs of up to 80%. Cognitive costs were even larger when rowing with the fast compared to the slow speed in study 1. Both studies also revealed decrements in motor performances under dual-task conditions: Rowing became slower and more irregular (study 1), and the quality of the Taekwondo performance was reduced. Although higher-level athletes outperformed others in motor skills under single-task conditions, proportional dual-task costs were similar across skill levels for most domains. This indicates that even well-practiced motor tasks require cognitive resources.

Application of mobile-based web app to enhance simple suturing skills of nurse practitioners

BACKGROUND

Suturing is a crucial clinical skill for nurse practitioners (NPs), but the effectiveness of traditional training methods (e.g., physical suture kits combined with video content) is low.

OBJECTIVE

This study compared the effectiveness and usability of a mobile-based web app (MoWa) developed for NPs to learn simple suturing skills with those of traditional instructional video-based training.

METHODS

The MoWa system utilizes mobile devices to simulate hands-on suturing and provides learning guidance and feedback to support self-learning with a physical suturing kit. Fifty-four suturing novices (NPs) were recruited as participants, divided into an experimental group (EG: 28 participants) and a control group (CG: 26 participants), and instructed to self-learn for 3 weeks. Learning effectiveness and system usability were evaluated through a pretest and posttest.

RESULTS

The EG exhibited significant improvements in learning outcomes, self-confidence, self-efficacy, and learning anxiety and expressed satisfaction with the MoWa system. Furthermore, the EG also considerably enhanced learning outcomes, self-efficacy, and learning anxiety compared to the CG, with no significant difference in self-confidence.

CONCLUSION

The MoWa system combined with deliberate practice is an effective strategy for supporting suturing skills training.

The Triple-E Model: Advancing Equestrian Research with Perspectives from One Health

Equestrian sport has various welfare issues and educational needs. To address these complex interactions, we propose an integrated approach called the Triple-E Model, which focuses on the equine, equestrian, and environmental triad. A literature review of existing models suggests that complexities of these interactions are overlooked, despite the significant impact of equine industries on economics, healthcare, and animal welfare. This paper discusses current models and theories used to evaluate equine-equestrian-environmental interactions and introduces the Triple-E Model to foster multidisciplinary collaboration. Unlike the One Health triad, which focuses on disease emergence, transmission, and zoonosis, the Triple-E Model extends to non-infectious research, such as musculoskeletal injury. It promotes collaborative care and rehabilitation within the equestrian community by engaging multidisciplinary, multi-setting, and multi-sectoral teams. Given the nature of human-animal interaction and welfare considerations, this model fills the gap in understanding human-horse interactions. The paper highlights the limitations of existing models and explains how the Triple-E Model guides and encourages holistic team collaboration in the equestrian community.

Touch may reduce cognitive load during assisted typing by individuals with developmental disabilities

Many techniques have attempted to provide physical support to ease the execution of a typing task by individuals with developmental disabilities (DD). These techniques have been controversial due to concerns that the support provider's touch can influence the typed content. The most common interpretation of assisted typing as an ideomotor phenomenon has been qualified recently by studies showing that users with DD make identifiable contributions to the process. This paper suggests a neurophysiological pathway by which touch could lower the cognitive load of seated typing by people with DD. The required sensorimotor processes (stabilizing posture and planning and executing manual reaching movements) and cognitive operations (generating and transcribing linguistic material) place concurrent demands on cognitive resources, particularly executive function (EF). A range of developmental disabilities are characterized by deficits in sensorimotor and EF capacity. As light touch has been shown to facilitate postural coordination, it is proposed that a facilitator's touch could assist the seated typist with sensorimotor and EF deficits by reducing their sensorimotor workload and thereby freeing up shared cognitive resources for the linguistic elements of the task. This is the first theoretical framework for understanding how a facilitator's touch may assist individuals with DD to contribute linguistic content during touch-assisted typing.

Reflecting on what is "skill" in human motor skill learning

Humans have an exceptional ability to execute a variety of skilled movements. Researchers have been long interested in understanding behavioral and neurophysiological basis of human motor skill learning for advancing both fundamental neuroscientific knowledge and clinical outcomes. However, despite decades of work in this field there is a lack of consensus about what is meant by "skill" in skill learning. With an advent of various task paradigms testing human motor behavior and increasing heterogeneity in motor learning assessments methods, it is very crucial to identify key features of skill in order to avoid any ambiguity that may result in misinterpretation or over-generalization of findings, which could have serious implications for replication and translational research. In this review, we attempt to highlight the features of skill following a historical approach, considering the seminal work that led to the first definitions of skill and including some contemporary concepts emerging from human motor learning research. Overall, based on this literature, we emphasize that skill has some fundamental characteristics, such as- (i) optimal movement selection and execution, (ii) improved movement speed and accuracy, and (iii) reduced movement variability and error. These features of skill can emerge as a consequence of extensive practice/training/learning, thus resulting in an improved performance state beyond baseline levels. Finally we provide some examples of model tasks that can appropriately capture these features of skill, and conclude that any neuroscientific endeavor aimed at understanding the essence of skill in human motor skill learning should focus on these aspects.

Toward a computational theory of manifold untangling: from global embedding to local flattening

It has been hypothesized that the ventral stream processing for object recognition is based on a mechanism called cortically local subspace untangling. A mathematical abstraction of object recognition by the visual cortex is how to untangle the manifolds associated with different object categories. Such a manifold untangling problem is closely related to the celebrated kernel trick in metric space. In this paper, we conjecture that there is a more general solution to manifold untangling in the topological space without artificially defining any distance metric. Geometrically, we can either embed a manifold in a higher-dimensional space to promote selectivity or flatten a manifold to promote tolerance. General strategies of both global manifold embedding and local manifold flattening are presented and connected with existing work on the untangling of image, audio, and language data. We also discuss the implications of untangling the manifold into motor control and internal representations.

Substituting some unassisted practice with robotic guidance: Assessing the feasibility of auditory-cued mixed practice for music-based interventions

BACKGROUND

There is equivocal evidence regarding the effectiveness of robotic guidance on the (re)learning of voluntary motor skills. Robotic guidance can improve the performance of continuous/ tracking skills, although being seldom more effective than unassisted practice alone. However, most of the previous studies employed robotic guidance on all intervention trials. Recently, we showed that mixing robotic guidance with unassisted practice (i.e., mixed practice) can significantly improve the learning of a golf putting task. Yet, these mixed practice studies involved self-paced movements in a standing posture, thus less applicable to rehabilitation contexts.

OBJECTIVE

The current study aimed to investigate the influence of mixed practice on the timing accuracy of an upper-limb, rhythmic, sequential task. The goal was to assess the feasibility of integrating mixed practice with music-based interventions.

METHODS

Two groups of participants performed circle-drawing sequences in synchrony with rhythmic auditory signals. They completed a pre-test and an acquisition phase, followed by immediate retention and transfer tests. One group received robotic guidance on 50% of the acquisition trials (i.e., mixed practice), whereas another group always practiced unassisted. The pre-test, retention, and transfer tests were performed unassisted.

RESULTS

Both groups significantly improved their timing accuracy and precision between the pre-test and the retention test.

CONCLUSION

This study provides further evidence that mixed practice can facilitate the (re)learning of voluntary actions, especially with the type of externally paced upper-limb movements employed in music-based interventions.

Enhanced expectancies benefit performance under distraction, but compromise it under stress: Exploring the OPTIMAL theory

Motor learning can benefit from practice under enhanced expectancies; that is, the belief one can generate an intended positive outcome. According to the OPTIMAL (Optimizing Performance Through Intrinsic Motivation and Attention for Learning) theory, this benefit manifests from a greater coupling between action and its external consequences, which potentially coincides with a more automatic mode of control. The aim of the study was to examine this possibility, and in so doing, understand more about the psycho-motor processes underpinning the influence of expectancies. On Day 1, novice participants practiced a dart-throwing task under enhanced (EE) (n = 11), reduced (RE) (n = 12) or no (control; CTL) (n = 12) expectancies. Enhanced and reduced expectancies were indirectly manipulated by positively reinforcing shots that landed within the large or small circle on the dartboard, respectively. On Day 2, participants transferred to a dual-task (i.e., tone-counting) or stress (i.e., social-comparative threat, false feedback) setting. While there was no evidence of improvement across practice, RE was significantly worse than CTL for the dual-task, but EE was significantly worse than RE and CTL under stress (ps < 0.05). Therefore, the ability of EE to retain performance within the dual-task, but decline under stress, suggests a more automatic mode of control was adopted. Both theoretical and practical implications are discussed.

Can different training methods reduce the kinematic risk factors of ACL injuries in children?

According to the research, a lack of neuromuscular control is a major cause of non-contact anterior cruciate ligament (ACL) injury during locomotion. This study aimed to determine the influence of various prescriptive and Constrained Led Approach (CLA) training approaches on lower extremity kinematics and stride length in children aged 3-5 years old while walking and running. Thirty-six children with a mean age of 4.79 years were separated into three groups: 1- prescriptive training group (n = 10), 2- CLA training group (n = 11), and 3- Control group (n = 10). The kinematics of the hip, knee and ankle joints in the sagittal plane at the moment of heel contact and toe-off were recorded before and after six weeks of intervention. According to the MANOVA, there was no statistically significant difference between the two training techniques in the joint angles at heel contact and toe-off during walking and running after intervention (p ≥ 0.05). However, there was a significant difference in the kinematic characteristics of walking and running between the training and the control groups (p ≤ 0.05). The two training techniques showed a statistically significant difference in stride length during running (p ≤ 0.05). The results indicated that prescriptive and CLA training are effective at altering the kinematics and distance factors underlying children's walking and running abilities.

In English Medium Instruction you can walk and chew gum

In English Medium Instruction (EMI), one of the biggest challenges is reportedly the teachers' own lack of English language proficiency. Helping teachers to improve their proficiency while learning about pedagogy is critical to achieving reasonable success in EMI. This article is contextualized in an English language teacher education program conducted in Tunisia. Specifically, I zoom in on a training task that had trainees reading an academic textbook and posting takeaways on an asynchronous platform over a four-week period. The corpus, comprising 50 journal entries produced by five teacher trainees, was analyzed, first using automated tools for natural language processing and then through human coding, for a combination of quantitative and qualitative perspectives, and with a view to deriving a comprehensive understanding of learning as manifested on multiple levels - psychological, cognitive, and linguistic. Results show impressive learning gains both in content and language. I conclude by discussing the findings and implications for EMI.

Semi-occluded Nasal Tract Exercises (SONTEs): Nasal Tube in Water Exercises Using Nasal Consonants

OBJECTIVE

This study analyzes the effects of the vocal exercises called semi-occluded nasal tract exercises (SONTEs), which were carried out with a new appliance that extends the nasal cavity as a part of the vocal tract. The acoustic, aerodynamic and electroglottographic (EGG) measurements were compared with those of the traditional semi-occluded vocal tract exercises (SOVTEs) of phonation in water.

METHODS

In this study, 34 women were randomly asked to perform phonation in water for 5 min through the nasal and oral routes with the sounds /m/ and /ɔ/, respectively, using a tube with a submersion depth of 5 cm. The acoustic, aerodynamic and EGG measurements before and after the exercises were analyzed using the appropriate statistical methods.

RESULTS

No significant difference was found in the time and frequency domain parameters before and after the exercises, except for the amplitude perturbation quotient (APQ) values, which decreased after both exercises. In addition, there was no significant difference in any aerodynamic parameters before and after the exercises, but the mean SPL values significantly increased after both exercises. The oral and nasal peak inspiratory flow rates increased after both exercises, but the increase peaked after the SONTEs implementation. As expected, the EGG-jitter and EGG-periodicity values had a reciprocal interaction with each other, while differences were observed between the values of the vocal fold movements measured in both exercises.

CONCLUSIONS

SONTEs may be as effective as the conventional SOVTEs because it made tube phonation into water possible through artificial extension of the nasal cavity and increased the resonant effect by using the positive effects based on the principles of SOVTEs.

Cognitive control, intentions, and problem solving in skill learning

We investigate flexibility and problem solving in skilled action. We conducted a field study of mountain bike riding that required a learner rider to cope with major changes in technique and equipment. Our results indicate that relatively inexperienced individuals can be capable of fairly complex 'on-the-fly' problem solving which allows them to cope with new conditions. This problem solving is hard to explain for classical theories of skill because the adjustments are too large to be achieved by automatic mechanisms and too complex and rapid to be achieved by cognitive processes as they are usually understood. A recent theory, Mesh, can explain these results because it posits that skill-specific cognitive abilities develop during skill learning and that control typically involves an interplay between cognitive and automatic mechanisms. Here we develop Mesh further, providing a detailed explanation for these problem solving abilities. We argue that causal representation, metacognitive awareness and other forms of performance awareness combine in the formulation and control of action strategies. We also argue that the structure of control present in this case is inconsistent with Bratman's model of intentions, and that, in the face of high uncertainty and risk, intentions can be much more labile than Bratman recognises. In addition, we found limitations and flaws in problem solving which illuminate the representations involved. Finally, we highlight the crucial role of social and cultural learning in the development of complex skills.

Sleep restriction impairs visually and memory-guided force control

Sleep loss is a common phenomenon with consequences to physical and mental health. While the effects of sleep restriction on working memory are well documented, it is unknown how sleep restriction affects continuous force control. The purpose of this study was to determine the effects of sleep restriction on visually and memory-guided force production magnitude and variability. We hypothesized that both visually and memory-guided force production would be impaired after sleep restriction. Fourteen men participated in an eleven-day inpatient sleep study and completed a grip force task after two nights of ten hours’ time in bed (baseline); four nights of five hours’ time in bed (sleep restriction); and one night of ten hours’ time in bed (recovery). The force task entailed four 20-second trials of isometric force production with the thumb and index finger targeting 25% of the participant’s maximum voluntary contraction. During visually guided trials, participants had continuous visual feedback of their force production. During memory-guided trials, visual feedback was removed for the last 12 seconds of each trial. During both conditions, participants were told to maintain the target force production. After sleep restriction, participants decreased the magnitude of visually guided, but not memory-guided, force production, suggesting that visual attention tasks are more affected by sleep loss than memory-guided tasks. Participants who reported feeling more alert after sleep restriction and recovery sleep produced higher force during memory-guided, but not visually guided, force production, suggesting that the perception of decreased alertness may lead to more attention to the task during memory-guided visual tasks.

Comparing the Effects of Differential Learning, Self-Controlled Feedback, and External Focus of Attention Training on Biomechanical Risk Factors of Anterior Cruciate Ligament (ACL) in Athletes: A Randomized Controlled Trial

The current study aimed to compare the possible effects of differential learning strategy, self-controlled feedback, and external focus of attention on kinetic and kinematic risk factors of anterior cruciate ligament (ACL) injury in athletes. Forty-eight male athletes from three sports of handball, volleyball and basketball were selected for this study and were randomly divided into four groups: differential learning (n = 12), self-control feedback (n = 12), external focus (n = 12), and control (n = 12) group. All groups followed the intervention for eight weeks with three sessions per week. Data were analyzed by means of 4 × 2 repeated measures ANOVA followed by post hoc comparison (Bonferroni) at the significance level of p ≤ 0.05. A significant group × time interaction and the main effect of time was found for most kinetic and kinematic variables. The main effect of the group was significant only at the knee abduction angle. Differential learning and external focus of attention methods positively reduced the kinetic and kinematic variables that are considered risk factors for ACL injury. However, the effect sizes (Cohen's d) for the changes in most of the variables were larger for the differential learning group. Tailoring the boundary conditions that are based on the manipulations created in the exercise through variability and variety of movements associated with differential learning methods rather than repeating movements could reduce the risk of ACL injury.

A Bibliometric and Visualization Analysis of Motor Learning in Preschoolers and Children over the Last 15 Years

Motor learning enables preschoolers and children to acquire fundamental skills that are critical to their development. The current study sought to conduct a bibliometric and visualization analysis to provide a comprehensive overview of motor-learning progress in preschoolers and children over the previous 15 years. The number of studies is constantly growing, with the United States and Australia, as well as other productive institutions and authors, at the leading edge. The dominant disciplines were Neurosciences and Neurology, Psychology, Rehabilitation, and Sport Sciences. The journals Developmental Medicine & Child Neurology, Human Movement Science, Physical Therapy, Neuropsychology, Journal of Motor Behavior, and Journal of Experimental Child Psychology have been the most productive and influential in this regard. The most common co-citations for clinical symptoms were for cerebral palsy, developmental coordination disorder, and autism. Research has focused on language impairment (speech disorders, explicit learning, and instructor-control feedback), as well as effective intervention strategies. Advances in brain mechanisms and diagnostic indicators, as well as new intervention and rehabilitation technologies (virtual reality, transcranial magnetic stimulation, and transcranial direct current stimulation), have shifted research frontiers and progress. The cognitive process is critical in intervention, rehabilitation, and new technology implementation and should not be overlooked. Overall, our broad overview identifies three major areas: brain mechanism research, clinical practice (intervention and rehabilitation), and new technology application.

EXPRESS: Perceptual scale expansion: A natural design for improving the precision of motor control

Space perception is systematically biased. Few theories of spatial bias address the possible functional advantages of mechanisms that produce spatial biases. The scale expansion hypothesis proposes that many spatial biases are due to the perceptual expansion of visual angles, which acts somewhat like a natural magnifying glass in vision. The present study examined the idea that visual expansion may improve motor precision (i.e., reduce motor variability) in movements when using closed-loop control but not when using open-loop control. Experiment 1 tested this idea in an online tracking task (closed-loop control), whereas Experiment 2 tested it in a fast-hitting task (open-loop control). The results were consistent with the hypothesis. To rule out the effect of the task difference (i.e., tracking vs. fast hitting), Experiment 3 examined the effect of visual expansion on the variability of motor performance in a line-reproduction task. The control type (closed-loop or open-loop) was manipulated by the form of visual feedback (online or offline). The results were again consistent with the present assumption. Taken together, the present data suggest that perceptual expansion in vision improves motor control precision when using closed-loop control (but not when using open-loop control), which supports the scale-expansion hypothesis. In addition, the present findings also improve our understanding of how visual error amplification affects motor control.

Turning a blind eye to motor differences leads to bias in estimating action-related auditory ERP attenuation

Event-related potential (ERP) studies investigating the processing of self-induced stimuli often rely on the assumption that ballistic actions and motor ERPs are constant across different sets of action effects. Since recent studies challenge this motor equivalence assumption, we examined whether neglecting effect-related motor differences can bias the estimation of auditory ERPs in a typical action-related ERP attenuation paradigm. We increased action variability with a force production task and selected an event subset in which the motor equivalence assumption was true. ERP attenuation estimated in this subset was compared with attenuation obtained in the standard task, where motor differences were not controlled. Violation of the motor equivalence assumption resulted in a positive deflection overlapping auditory ERPs elicited by self-induced sounds, resulting in the overestimation of N1- and underestimation of P2-attenuation. This demonstrates that sensory-effect-related motor differences should be considered when separating sensory and motor components in ERPs elicited by self-induced stimuli.

Binding of Task-Irrelevant Action Features and Auditory Action Effects

Discrete task-relevant features of an overt response, such as response location, are bound to, and retrieved by coincidentally occurring auditory stimuli. Here we studied whether continuous, task-irrelevant response features like force or response duration also become bound to, and retrieved by such stimuli. In two experiments we asked participants to carry out a pinch which produced a certain auditory effect in a prime part of each trial. In a subsequent probe part, tones served as imperative stimuli which either repeated or changed as compared to the effect tone in the prime. We conjectured that the repetition of tones should result in more similar responses in terms of force output and duration as compared to tone changes. Most parameters did not show notable indications for such similarity increases, including peak force or area under force curve, though the correlation between response durations in prime and probe was higher when tones repeated rather than changed from prime to probe. We discuss these results regarding perceptual discriminability and deployment of attention to different nominally task-irrelevant aspects of pinch responses.

A conceptual model for clinical psychomotor skill development in an era of simulated and virtual reality

Psychomotor skill development is central to a beginner practitioner's learning pathway. Curriculum constraints around time, access to facilities and resources in health professions education have prompted the growth in alternative approaches to clinical skill development in both simulation and direct patient care. Among these is the increased incorporation of virtual reality (VR) systems with haptic feedback alongside traditional, solid simulations. Given the rapid growth in the adoption of technological affordances to support skill development, it is cogent to pause and examine whether the underpinning concepts regarding psychomotor skill development that have driven much of the approaches to teach clinical skill acquisition in dentistry remain fit-for-purpose. This conceptual paper proposes a new taxonomy for clinical simulation psychomotor skill development in the era of increasing variety of simulation modalities.

Vibrotactile feedback in virtual motor learning: A systematic review

Vibrotactile feedback can be effectively applied to motor (physical) learning in virtual environments, as it can provide task-intrinsic and augmented feedback to users, assisting them in enhancing their motor performance. This review investigates current uses of vibrotactile feedback systems in motor learning applications built upon virtual environments by systematically synthesizing 24 peer-reviewed studies. We aim to understand: (1) the current state of the science of using real-time vibrotactile feedback in virtual environments for aiding the acquisition (or improvement) of motor skills, (2) the effectiveness of using vibrotactile feedback in such applications, and (3) research gaps and opportunities in current technology. We used the Sensing-Analysis-Assessment-Intervention framework to assess the scientific literature in our review. The review identifies several research gaps in current studies, as well as potential design considerations that can improve vibrotactile feedback systems in virtual motor learning applications, including the selection and placement of feedback devices and feedback designs.

Are they really motor learning therapies? A scoping review of evidence-based, task-focused models of upper limb therapy for children with unilateral cerebral palsy

PURPOSE

To identify the specific motor learning (ML) theories underpinning evidence-based, task-focused upper limb models of therapy for children with unilateral cerebral palsy; and to document the strategies used in the operationalisation of these theories.

MATERIAL AND METHOD

This scoping review searched for relevant studies using eight electronic databases. A list of 68 ML strategies and accompanying definitions was developed for data extraction. Three classifications; adequate, inadequate or not described were used to rate the description of ML strategies. A corresponding colour-coding system was used to provide a visual summary.

RESULTS

There is a limited description of the ML theories and strategies used to operationalise these theories in existing models of evidence-based upper limb therapy. Of 103 therapy protocols included, only 24 explicitly described the guiding ML theory. When described, there was significant variation in the underlying theories, leading to significantly different focus and content of therapy. Of the 68 ML strategies, only three were adequately described.

CONCLUSIONS

To support treatment fidelity and the implementation of evidence-based, task-focused models of upper limb therapy in clinical practice, future research needs to provide explicit details about the underlying theories and strategies used in the operationalisation of these theories.Implications for rehabilitationEvidence-based models of upper limb therapy purport to be based on motor learning theory, however, most provide a very limited description of the theories and strategies used.Dosage of practice is only one element that is specific to a therapy approach and other elements guided by the principles of type of task and type of feedback should be considered.To support the implementation of evidence-based approaches in clinical practice, and improve treatment fidelity, it is important for researchers to define the theories that guide therapy approaches and explicitly describe the strategies used to operationalise these theories.

A Haptic Sleeve as a Method of Mechanotactile Feedback Restoration for Myoelectric Hand Prosthesis Users

Current myoelectric upper limb prostheses do not restore sensory feedback, impairing fine motor control. Mechanotactile feedback restoration with a haptic sleeve may rectify this problem. This randomised crossover within-participant controlled study aimed to assess a prototype haptic sleeve's effect on routine grasping tasks performed by eight able-bodied participants. Each participant completed 15 repetitions of the three tasks: Task 1—normal grasp, Task 2—strong grasp and Task 3—weak grasp, using visual, haptic, or combined feedback All data were collected in April 2021 in the Scottish Microelectronics Centre, Edinburgh, UK. Combined feedback correlated with significantly higher grasp success rates compared to the vision alone in Task 1 (p < 0.0001), Task 2 (p = 0.0057), and Task 3 (p = 0.0170). Similarly, haptic feedback was associated with significantly higher grasp success rates compared to vision in Task 1 (p < 0.0001) and Task 2 (p = 0.0015). Combined feedback correlated with significantly lower energy expenditure compared to visual feedback in Task 1 (p < 0.0001) and Task 3 (p = 0.0003). Likewise, haptic feedback was associated with significantly lower energy expenditure compared to the visual feedback in Task 1 (p < 0.0001), Task 2 (p < 0.0001), and Task 3 (p < 0.0001). These results suggest that mechanotactile feedback provided by the haptic sleeve effectively augments grasping and reduces its energy expenditure.

The role of feedback in the production of skilled finger sequences

Actions involving fine control of the hand, for example, grasping an object, rely heavily on sensory information from the fingertips. Although the integration of feedback during the execution of individual movements is well understood, less is known about the use of sensory feedback in the control of skilled movement sequences. To address this gap, we trained participants to produce sequences of finger movements on a keyboard-like device over a 4-day training period. Participants received haptic, visual, and auditory feedback indicating the occurrence of each finger press. We then either transiently delayed or advanced the feedback for a single press by a small amount of time (30 or 60 ms). We observed that participants rapidly adjusted their ongoing finger press by either accelerating or prolonging the ongoing press, in accordance with the direction of the perturbation. Furthermore, we could show that this rapid behavioral modulation was driven by haptic feedback. Although these feedback-driven adjustments reduced in size with practice, they were still clearly present at the end of training. In contrast to the directionally specific effect we observed on the perturbed press, a feedback perturbation resulted in a delayed onset of the subsequent presses irrespective of perturbation direction or feedback modality. This observation is consistent with a hierarchical organization of even very skilled and fast movement sequences, with different levels reacting distinctly to sensory perturbations.NEW & NOTEWORTHY Sensory feedback is important during the execution of a movement. However, little is known about how sensory feedback is used during the production of movement sequences. Here, we show two distinct feedback processes in the execution of fast finger movement sequences. By transiently delaying or advancing the feedback of a single press within a sequence, we observed a directionally specific effect on the perturbed press and a directionally non-specific effect on the subsequent presses.

Autonomy Support via Instructionally Irrelevant Choice Not Beneficial for Motor Performance or Learning

Purpose: The Optimizing Performance Through Motivation and Attention for Learning (OPTIMAL) theory predicts that providing learners with choices during skill acquisition will enhance their acquisition performance, motor learning, and expectancies. Based on this theory, it is recommended that instructors ask learners to choose which tasks to practice in applied settings. This experiment tested these predictions and recommendation by crossing autonomy support with practice schedule in a 2 × 2 factorial design. Method: Participants (N = 128) practiced a novel non-dominant hand dart-throwing task either with choice over the color of the dart flights (autonomy) or yoked to a counterpart's choices (yoked). Further, participants either practiced throwing darts to three different targets in equal amounts (variable) or throwing to the same target for all practice trials (constant). All participants completed a pretest, acquisition phase, 24-hr delayed retention and transfer tests, as well as baseline and post-acquisition autonomy, and self-efficacy measures. Data were analyzed according to a pre-registered analysis plan that included pretest and gender as covariates. Results: The autonomy groups reported significantly greater perceived autonomy at the end of acquisition. There were no significant effects of autonomy on self-efficacy, or motor performance uniquely during acquisition, or uniquely on the delayed transfer test. The autonomy groups, however, performed with significantly greater error across acquisition and transfer. Practice schedule interacted with the time of testing such that the constant groups performed significantly more accurately during acquisition but non-significantly less accurately during transfer than the variable groups. Conclusions: These results are inconsistent with OPTIMAL theory.

Electrical stimulation and virtual reality-guided balance training for managing paraplegia and trunk dysfunction due to spinal cord infarction

A 41-year-old woman presented with spinal cord infarction and paraplegia after acute thoracoabdominal aortic dissection. Clinical evaluation revealed the American Spinal Injury Association (ASIA) lower limb exercise score of 0 points and the Functional Assessment for Control of Trunk (FACT) score of 0 points. Conventional physical therapy for 60 days did not significantly improve the paraplegia or FACT score; therefore, belt electrode skeletal muscle electrical stimulation (B-SES) and virtual reality (VR)-guided sitting balance training were introduced for 30 days. She developed independence for all basic movements and her gait was restored using short leg braces and Lofstrand crutches. At discharge, her ASIA lower limb exercise score was 24 and FACT score was 7, with a functional impedance measure motor item of 57, and she could continuously walk for a distance of 150 m. The combination of B-SES and VR-guided balance training may be a feasible therapeutic option after spinal cord infarction.

Table tennis expertise influences dual-task costs in timed and self-initiated tasks

Theories on resource sharing predict that performances will suffer under dual-task conditions. However, increases in skill level should decrease attentional resources needed to perform a task, resulting in a reduction of dual-task costs. The current study investigates whether table tennis experts are better able than novices to keep up their motor and cognitive performances in a dual-task situation. Two different cognitive tasks, 3-back and Counting Backwards in steps of 7, and two different table tennis tasks, returns and serves, were assessed in each possible cognitive-motor task combination in a within-subjects design. While 3-back and returns were timed, Counting Backwards and serves were self-initiated. We assumed that self-initiated tasks increase dual-task costs, since the scheduling of the responses requires attentional resources. As predicted, dual-task costs of novices were considerably higher (35%) than those of experts, who did not show costs (-1%). The predicted increase of costs for self-initiated tasks was only observed in the experts, while novices showed a tendency to reduce their dual-task costs for self-initiated tasks. It is argued that this is due to the psychometric properties of the underlying task, since timed tasks were specified by a fixed number of targets and responses. We conclude that cognitive-motor dual-task costs may be a valuable measure of sporting skill, over and above "pure" motor or cognitive performances.

Tennis expertise reduces costs in cognition but not in motor skills in a cognitive-motor dual-task condition

Dual-process theories predict performance reductions under dual-task situations (= situations where two tasks have to be processed and executed simultaneously), because limited cognitive resources have to be shared between concurrent tasks. Increases in expertise should reduce the attentional resources needed to perform a motor task, leading to reduced dual-task costs. The current studies investigated whether expert tennis players (performance ratings of 1 to 14 in the German system) show smaller costs compared to intermediate players (performance ratings of 15 to 23). Two studies assessed single- and dual-task performance in a within-subject design in the same tennis task, returning balls into a target field. Two different cognitive tasks were used, a 3-back working memory task in study 1, and a vocabulary-learning task (episodic memory) in study 2. As predicted, performance in both cognitive tasks was reduced during dual-tasking, while the accuracy of tennis returns remained stable under cognitive challenge. These findings indicate that skilled tennis players show a task-prioritization strategy in favor of the tennis task in a dual-task situation. In study 1, intermediate players showed higher overall dual-task costs than experts, but the group differences in dual-task costs did not reach significance in study 2. This may have been due to less pronounced expertise-differences between the groups in study 2. The findings replicate and extend previous expertise studies in sports to the domain of tennis. We argue that an athlete's ability to keep up cognitive and motor performances in challenging dual-task situations may be a valid indicator of skill level.

Role of Post-Trial Visual Feedback on Unintentional Force Drift During Isometric Finger Force Production Tasks

A reduction in fingertip forces during a visually occluded isometric task is called unintentional drift. In this study, unintentional drift was studied for two conditions, with and without "epilogue." We define epilogue as the posttrial visual feedback in which the outcome of the just-concluded trial is shown before the start of the next trial. For this study, 14 healthy participants were recruited and were instructed to produce fingertip forces to match a target line at 15% maximum voluntary contraction. The results showed a significant reduction in unintentional drift in the epilogue condition. This reduction is probably due to the difference in the shift in λ, the threshold of the tonic stretch reflex, the hypothetical control variable that the central controller can set.

Virtual reality (VR) as a simulation modality for technical skills acquisition

Efforts continue to facilitate surgical skills training and provide accessible and safe training opportunities. Educational technology has played an essential role in minimizing the challenges facing traditional surgical training and providing feasible training opportunities. Simulation and virtual reality (VR) offer an important innovative training approach to enhance and supplement both technical and non-technical skills acquisition and overcome the many training challenges facing surgical training programs. To maximize the effectiveness of simulation modalities, an in-depth understanding of the cognitive learning theory is necessary. Knowing the stages and mental processes of skills acquisition when integrated with simulation applications can help trainees achieve maximal learning outcomes. This article aims to review important literature related to VR effectiveness and discuss the leading theories of technical skills acquisition related to VR simulation technologies.

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VR simulation offers an innovative training approach to supplement both technical and non-technical skills acquisition.

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VR simulation with haptic feedback is a promising modality for safe, repetitive, and learner-oriented operative training.

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VR simulation facilitates deliberate practice with built-in auto feedback to address limited staff resources.

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To maximize the effectiveness of simulation, an in-depth understanding of the cognitive learning theory is necessary.

Effects of Different Forms of Extrinsic Feedback on the Accuracy of Force Production and to Differentiate this Force in the Simple Cyclic Movements of the Upper and Lower Limb

Background: This study aimed to assess the accuracy of force production by the limbs and to identify the ability to differentiate this force during a progressively increasing value, in response to different types of extrinsic feedback.

Material and methods: The study involved nineteen healthy and physically active boys and girls aged 12.82±0.34 years, body height 157.05±9.02 cm, and body mass 44.89±7.89 kg. The tasks were to perform a series of right and left upper limb pulls and pushes with increasing force using the levers of the kinesthesiometer and a series of lower limb presses on the pedal of the kinesthesiometer. The tasks were completed in three feedback conditions: no feedback, sound feedback, verbal feedback, and the retention test was used. To assess the level of accuracy of force production, the novel index of force production accuracy (FPAIndex) was used.

Results: The outcomes expressing the value of FPAIndex on the point scale indicated that the highest level of kinesthetic differentiation was observed when no feedback was provided (1.17 points), and the lowest kinesthetic differentiation was recorded when verbal feedback was provided (3.33 points). However, they were devoid of statistical value. The repeated-measures analysis of variance ANOVA with the Tukey post-hoc test (HSD) indicated a significant lowest (p=0.0402) level of accuracy of FPA (x̄ 36.12±18.29 [N]) only for the act of left lower limb press (LL PRESS) in the retention test, while no feedback was provided to the subjects.

Conclusions: The results of this study showed that verbal and sound extrinsic feedback did not affect the accuracy of force production by the upper and lower limbs and the ability to differentiate this force in simple movements among children.

Can acute resistance exercise facilitate episodic memory encoding?

Research has shown benefits of physical exercise on memory performance when carried out before or after a memory task. The effects of concurrent physical exercise and particularly resistance exercise are still inconclusive. The current study investigates the influence of resistance exercise with two intensities (fast and slow squats) on performance in a wordlist learning task using a within-subject design. Sport students (N = 58, Mage = 23 years; 26 women) were trained in a mnemonic technique to encode word lists (method of loci). In each session they were asked to encode two lists, each consisting of 20 words. During encoding, participants either performed one squat per word (fast-squat-condition), one squat every second word (slow-squat-condition), or stayed seated (control-condition). Participants performed three sessions for each condition, in counterbalanced order. Heart rates differed significantly according to exercise intensity. Memory performances in the sitting condition were better, compared to the exercise conditions. Performance in sitting and the fast squat conditions improved similarly over time, while performance in the slow squat condition increased faster, and reached the level of the fast squat condition at the end of the study phase. We conclude that light to moderate resistance exercise while working on an episodic memory task may rather represent a dual-task situation (= two tasks that compete for attentional resources). Especially doing a squat every second word may represent an inhibition task that people have to get used to. Future studies should include biochemical markers of arousal and neuronal plasticity in addition to heart rate.

Cognitive & motor skill transfer across speeds: A video game study

We examined the detailed behavioral characteristics of transfer of skill and the ability of the adaptive control of thought rational (ACT-R) architecture to account for this with its new Controller module. We employed a simple action video game called Auto Orbit and investigated the control tuning of timing skills across speed perturbations of the environment. In Auto Orbit, players needed to learn to alternate turn and shot actions to blow and burst balloons under time constraints imposed by balloon resets and deflations. Cognitive and motor skill transfer was assessed both in terms of game performance and in terms of the details of their motor actions. We found that skill transfer across speeds necessitated the recalibration of action timing skills. In addition, we found that acquiring skill in Auto Orbit involved a progressive decrease in variability of behavior. Finally, we found that players with higher skill levels tended to be less variable in terms of action chunking and action timing. These findings further shed light on the complex cognitive and motor mechanisms of skill transfer across speeds in complex task environments.

How adaptation, training, and customization contribute to benefits from exoskeleton assistance

Exoskeletons can enhance human mobility, but we still know little about why they are effective. For example, we do not know the relative importance of training, how much is required, or what type is most effective; how people adapt with the device; or the relative benefits of customizing assistance. We conducted experiments in which naïve users learned to walk with ankle exoskeletons under one of three training regimens characterized by different levels of variation in device behavior. Assistance was also customized for one group. After moderate-variation training, the benefits of customized assistance were large; metabolic rate was reduced by 39% compared with walking with the exoskeleton turned off. Training contributed about half of this benefit and customization about one-quarter; a generic controller reduced energy cost by 10% before training and 31% afterward. Training required much more exposure than typical of exoskeleton studies, about 109 minutes of assisted walking. Type of training also had a strong effect; the low-variation group required twice as long as the moderate-variation group to become expert, and the high-variation group never acquired this level of expertise. Curiously, all users adapted in a way that resulted in less mechanical power from the exoskeleton as they gained expertise. Customizing assistance required less time than training for all parameters except peak torque magnitude, which grew slowly over the study, suggesting a longer time scale adaptation in the person. These results underscore the importance of training to the benefits of exoskeleton assistance and suggest the topic deserves more attention.

Slacklining: A narrative review on the origins, neuromechanical models and therapeutic use

Slacklining, the neuromechanical action of balance retention on a tightened band, is achieved through self-learned strategies combining dynamic stability with optimal energy expenditure. Published slacklining literature is recent and limited, including for neuromechanical control strategy models. This paper explores slacklining's definitions and origins to provide background that facilitates understanding its evolution and progressive incorporation into both prehabilitation and rehabilitation. Existing explanatory slacklining models are considered, their application to balance and stability, and knowledge-gaps highlighted. Current slacklining models predominantly derive from human quiet-standing and frontal plane movement on stable surfaces. These provide a multi-tiered context of the unique and complex neuro-motoric requirements for slacklining's multiple applications, but are not sufficiently comprehensive. This consequently leaves an incomplete understanding of how slacklining is achieved, in relation to multi-directional instability and complex multi-dimensional human movement and behavior. This paper highlights the knowledge-gaps and sets a foundation for the required explanatory control mechanisms that evolve and expand a more detailed model of multi-dimensional slacklining and human functional movement. Such a model facilitates a more complete understanding of existing performance and rehabilitation applications that opens the potential for future applications into broader areas of movement in diverse fields including prostheses, automation and machine-learning related to movement phenotypes.

Understanding Motor Skill Learning as Related to Dentistry

Learning dental procedures is a complex task involving the development of fine motor skills. The reported use of theories and/or evidence for designing learning activities to develop the fine motor skills needed for dental practice is limited. The aim of this review is to explore the available body of knowledge related to learning motor skills relevant to dentistry. Evidence from studies investigating motor skill learning highlights the negative impact of self-focus and self-regulation on learning outcomes, particularly during the early stages of learning. The development of activities and schedules that enable novices to demonstrate characteristics similar to experts, without the reported long period of 'deliberate practice', is clearly of value. Outcomes of learning implicitly are important in dentistry because working under stressful conditions is common, either during undergraduate study or in practice. It is suggested that learning implicitly in the simulation stage can reduce disrupted performance when transitioning to clinical settings. Therefore, further investigation of effective methods for learning dental fine motor skills is indicated, using approaches that result in robust performance, even under stressful conditions.

A case for the role of memory consolidation in speech-motor learning

This review will explore the role of memory consolidation in speech-motor learning. Existing frameworks of speech-motor control account for the protracted time course of building the speech-motor representation. These perspectives converge on the speech-motor representation as a multimodal unit that is comprised of auditory, motor, and linguistic information. Less is known regarding the memory mechanisms that support the emergence of a generalized speech-motor unit from instances of speech production. Here, we consider the broader learning and memory consolidation literature and how it may apply to speech-motor learning. We discuss findings from relevant domains on the stabilization, enhancement, and generalization of learned information. Based on this literature, we provide our predictions for the division of labor between conscious and unconscious memory systems in speech-motor learning, and the subsequent effects of time and sleep to memory consolidation. We identify both the methodological challenges, as well as the practical importance, of advancing this work empirically. This discussion provides a foundation for building a memory-based framework for speech-motor learning.

Effects of bi-axial ankle strengthening on muscle co-contraction during gait in chronic stroke patients: A randomized controlled pilot study

INTRODUCTION

Ankle dysfunction in patients with stroke is a common but serious cause of balance and gait impairments. However, comprehensive paretic ankle training seldom exists. Thus, we investigated the effects of a bi-axial ankle muscle training program using visual feedback as a means to improve ankle strength and performance of functional activities in patients with stroke.

METHODS

This study was a randomized controlled pilot trial with concealed allocation and assessor blinding and intention-to-treat analysis. Twenty-five patients with stroke and difficulty in walking (e.g., foot drop) or ankle muscle weakness receiving inpatient rehabilitation were included. The experimental group underwent ankle muscle training consisting of passive stretching, control of ankle muscles, and active-resistive strengthening using visual feedback for 40 min per day, 5 times per week for 4 weeks. The control group underwent ankle-related physical therapy, including ankle range-of-motion exercises. The amount of time for training was equal between the two groups. The outcome measurements were isometric ankle contraction force to assess the strength of ankle muscles, ankle proprioception, Fugl-Meyer lower extremity score, Berg balance scale score, walking speed, and ankle co-contraction index to assess muscle efficiency during gait.

RESULTS

The analysis revealed significant between-group differences in the ankle muscle strength in each direction (P < 0.05), Fugl-Meyer score (P < 0.01), and stance-phase co-contraction index (P < 0.05). After training, the experimental group displayed significant within-group differences in the strength of the ankle muscles in each direction (P < 0.01), ankle proprioception (P < 0.05), and walking speed (P < 0.05).

CONCLUSIONS

Our findings demonstrate the significant short-term effects of ankle muscle training on strength, walking speed, and muscle efficiency in patients with chronic stroke.

Effects of biofeedback on whole lower limb joint kinematics and external kinetics

Biofeedback (BFb) is a useful tool to accelerate the skill development process. Limited research has applied BFb to the whole lower-limb in a complex skill therefore the aim of this research was to assess the effectiveness of a biofeedback intervention targeting whole lower limb kinematics. Thirty-two healthy participants were randomized to a BFb (n = 16) and a Control group (n = 16). Participants visited a motion capture laboratory on three occasions during one week, and returned for retention testing at 4-6 weeks. Following introduction to a novel lunge-touch task, visual BFb on lower limb joint kinematic extension angular velocities (ω) and timing were provided following each lunge. BFb was effective in increasing Hipω (F = 3.746, p = 0.03) and Kneeω (F = 10.241, p = 0.01). Peak Ankle_ω remained unchanged (F = 1.537, p = 0.23, η² = 0.05), however Peak Ankle_θ (F = 10.915, p < 0.001, η² = 0.27) and Ankle_ROM (F = 9.543, p < 0.001, η² = 0.24) significantly increased. Despite kinematic changes, there were no significant changes in any external kinetics. No significant correlations were found between Hipω, Kneeω or Ankleω and horizontal impulse (Impulse_Y: r = 0.20, p = 0.26; r = -0.11, p = 0.24; and r = 0.22, p = 0.28, respectively). Findings demonstrate that BFb can be used to alter multiple kinematic variables in a complex skill, but do not necessarily alter associated kinetic variables not directly targeted by BFb.

The relationship between the implicit visuomotor control and the motor planning accuracy

It has been well established that an implicit motor response can be elicited by a target perturbation or a visual background motion during a reaching movement. Computational studies have suggested that the mechanism of this response is based on the error signal between the efference copy and the actual sensory feedback. If the implicit motor response is based on the efference copy, the motor command accuracy would affect the amount of the modulation of the motor response. Therefore, the purpose of the current study was to investigate the relationship between the implicit motor response and the motor planning accuracy. We used a memory-guided reaching task and a manual following response (MFR) which is induced by visual grating motion. Participants performed reaching movements toward a memorized-target location with a beep cue which was presented 0 or 3 s after the target disappeared (0-s delay and 3-s delay conditions). Leftward or rightward visual grating motion was applied 400 ms after the cue. In addition, an event-related potential (ERP) was recorded during the reaching task, which reflects the motor command accuracy. Our results showed that the N170 ERP amplitude in the parietal electrodes and the MFR amplitude were significantly larger for the 3-s delay condition than the 0-s delay condition. These results suggest that the motor planning accuracy affects the amount of the implicit visuomotor response. Furthermore, there was a significant within-subjects correlation between the MFR and the N170 amplitude, which could corroborate the relationship between the implicit motor response and the motor planning accuracy.

Motor learning methods that induce high practice variability reduce kinematic and kinetic risk factors of non-contact ACL injury

The prevention of non-contact anterior cruciate ligament (ACL) injuries often involves movement training, but the effectiveness of different motor learning methods has not been fully investigated. The purpose of this study was therefore to examine the effects of linear pedagogy (LP), nonlinear pedagogy (NLP) and differential learning (DL) motor learning methods on changing kinetic and kinematic factors during expected sidestep cutting related to non-contact ACL injuries. These methods primarily differ in the amount and type of movement variability they induce during practice. Sixty-six beginner male soccer players (27.5 ± 2.7 years, 180.6 ± 4.9 cm, 78.2 ± 4.6 kg) were randomly allocated to a group that trained for 12 weeks with either a LP, NLP or DL type of motor learning methods. All participants completed a biomechanical evaluation of side-step cutting before and after the training period. Analysis of covariance was used to compare post-testing outcomes among the groups while accounting for group differences in baseline performance. Changes in all kinematic and kinetic variables in NLP and DL groups were significantly higher compared to the LP group. Most comparisons were also different between NLP and DL group with the exception of vertical ground reaction force, the knee extension/flexion, knee valgus, and ankle dorsiflexion moments. Our findings indicate that beginner male soccer players may benefit from training programs incorporating NLP or DL versus LP to lower biomechanical factors associated with non-contact ACL injury, most likely because of the associated increased execution variability during training. We discuss that practitioners should consider using the NLP or DL methods, and particular the NLP, during which variability is induced to guide search, when implementing training programs to prevent ACL injuries in soccer.

Considerations for Velocity-Based Training: The Instruction to Move "As Fast As Possible" Is Less Effective Than a Target Velocity

ABSTRACT

Hirsch, SM and Frost, DM. Considerations for velocity-based training: the instruction to move "as fast as possible" is less effective than a target velocity. J Strength Cond Res 35(2S): S89-S94, 2021-In addition to the potential benefits with monitoring training intensity with velocity-measuring tools during exercise, these devices also provide an opportunity for researchers and practitioners to provide feedback and instruction to performers in a new way. The purpose of this study was to assess the influence of instructing athletes with a target velocity vs. instructing them to move "as fast as possible" during a free-weight bench press. In addition, the effects of each instruction on future repetition maximum (RM) test performance was compared. Thirteen male powerlifters were recruited and performed 4 sets of 5 repetitions with 45% 1RM while being instructed to attain a target velocity of 1.0 m·s-1 or to move as fast as possible. The maximum mean velocity attained in each set was compared with a repeated measures analysis of variance and Tukey's post-hoc test. After these 4 sets of 5 repetitions, the number of repetitions performed during an RM test with 75% 1RM was compared with a Wilcoxon Signed-Rank test. Participants moved faster when they received the target velocity instruction (0.84 ± 0.10 m·s-1) than when they received the "move as fast as possible" instruction (0.82 ± 0.09 m·s-1) (p < 0.001) with no differences in the number of repetitions performed in the following RM test between the 2 testing sessions (p = 0.43). An instruction to attain a challenging velocity target may be a more effective strategy to use when attempting to elicit maximum barbell velocities during training relative to the traditional instruction to move as fast as possible.