Especial skills: their emergence with massive amounts of practice

Applying different levels of practice variability for motor learning: More is not better

Background

Variable practice is a broadly used tool to improve motor learning processes. However, controversial results can be found in literature about the success of this type of practice compared to constant practice. This study explored one potential reason for this controversy: the manipulation of variable practice load applied during practice and its effects according to the initial performance level and the initial intrinsic variability of the learner.

Method

Sixty-five participants were grouped into four practice schedules to learn a serial throwing task, in which the training load of variable practice was manipulated: one constant practice group and three groups with different variable practice loads applied. After a pre-test, participants trained for 2 weeks. A post-test and three retests (96 h, 2 weeks and 1 month) were carried out after training. The participants' throwing accuracy was assessed through error parameters and their initial intrinsic motor variability was assessed by the autocorrelation coefficient of the error.

Results

The four groups improved their throwing performance. Pairwise comparisons and effect sizes showed larger error reduction in the low variability group. Different loads of variable practice seem to induce different performance improvements in a throwing task. The modulation of the variable practice load seems to be a step forward to clarify the controversy about its benefits, but it has to be guided by the individuals' features, mainly by the initial intrinsic variability of the learner.

Relationship between skill training and skill transfer through the example of bimanual motor learning

Skill training aims to improve the performance of the task at hand and aims to transfer the acquired skill to related tasks. Both skill training and skill transfer are part of our everyday lives, and essential for survival, and their importance is reflected in years of research. Despite these enormous efforts, however, the complex relationship between skill training and skill transfer is not yet portrayed completely. Building upon two theories, we probed this relationship through the example of bimanual learning with a large cross-sectional design (N = 450) using an online framework. We designed five training tasks which differed in the variance of the training material (schema theory) and three transfer tasks differing in their similarity to the training task (identical elements theory). Theoretically, the five training tasks and the three transfer tasks varied approximately linearly from each other. Empirical data, however, suggested merely the presence of three statistically different training tasks and two significantly different transfer tasks, indicating a nonlinear relationship. Against our expectation, Bayesian statistics suggested that the type of skill training was not related to the type of skill transfer. However, the amount of skill training was positively related to the amount of skill transfer. Together, we showed that motor learning studies can be conducted online. Further, our results shed light on the complex relationship between skill training and skill transfer. Understanding this relationship has wide-ranging practical implications for the general population, particularly for musicians, athletes and patients recovering from injury.

Distinct clusters of movement entropy in children's exploration of a virtual reality balance beam

Although assessing motor competence is vital to advancing current understandings of motor development and its significance in various fields, no consensus exists on how the construct should be operationalised and measured. Existing approaches to assessing motor competence in children typically involve applying qualitative and/or quantitative scoring procedures in which children's performance is evaluated according to certain levels of assessment-specific task performance dependent upon predefined sets of instructions and procedures. Building upon ecological dynamics as a framework, different levels of motor competence can be identified in children's attempts to coordinate their degrees of freedom while trying to complete the interactive task and environmental constraints. Given the dynamic, nonlinear features of that coordinating process, assessments need to consider the inherit structure of inter- and intra-individual variability in patterns of movement. Against that background, we investigated 7-10-year-old children's (n = 58) whole-body joint kinematics as they freely explored a balance beam in a virtual reality playground. Specifically, we used exploratory cluster analysis to examine the discriminatory capability of utilising joint-specific sample entropy as a window into individual differences in movement coordination that emerged from children's exploration of the constraints embedded in the virtual task. Among the results, three clusters of children with distinct profiles of movement variability emerged, all of which showed heterogeneous levels of repeatability in joint movements in combination with the level of spatiotemporal exploration on the balance beam that could not be explained by between-cluster differences in age and gender distributions. Those findings suggest that entropy from whole-body movements can be used to cluster children into distinct groups with different profiles regarding the structure of movement variability, which can inform new understandings and the development of gross motor competence assessments for children.

The Critical Period After Stroke Study (CPASS) Upper Extremity Treatment Protocol

Objective

To present the development of a novel upper extremity (UE) treatment and assess how it was delivered in the Critical Periods After Stroke Study (CPASS), a phase II randomized controlled trial (RCT).

Design

Secondary analysis of data from the RCT.

Setting

Inpatient and outpatient settings the first year after stroke.

Participants

Of the 72 participants enrolled in CPASS (N=72), 53 were in the study groups eligible to receive the treatment initiated at ≤30 days (acute), 2-3 months (subacute), or ≥6 months (chronic) poststroke. Individuals were 65.1±10.5 years of age, 55% were women, and had mild to moderate UE motor capacity (Action Research Arm Test=17.2±14.3) at baseline.

Intervention

The additional 20 hours of treatment began using the Activity Card Sort (ACS), a standardized assessment of activities and participation after stroke, to identify UE treatment goals selected by the participants that were meaningful to them. Treatment activities were broken down into smaller components from a standardized protocol and process that operationalized the treatments essential elements.

Main Outcome Measures

Feasibility of performing the treatment in a variety of clinical settings in an RCT and contextual factors that influenced adherence.

Results

A total of 49/53 participants fully adhered to the CPASS treatment. The duration and location of the treatment sessions and the UE activities practiced during therapy are presented for the total sample (n=49) and per study group as an assessment of feasibility and the contextual factors that influenced adherence.

Conclusions

The CPASS treatment and therapy goals were explicitly based on the meaningful activities identified by the participants using the ACS as a treatment planning tool. This approach provided flexibility to customize UE motor therapy without sacrificing standardization or quantification of the data regardless of the location and UE impairments of participants within the first year poststroke.

Insights into motor memory interference among experts and competent individuals

Memory interference can arise when multiple motor skill tasks are learned. A study by Nepotiuk and Brown (Nepotiuk AH, Brown LE. J Neurophysiol 128: 969-981, 2022) demonstrated that the susceptibility of motor memory to interference differs depending on expertise, using a vegetable-chopping task. The authors suggest that the motor memories of expert chefs and competent home cooks are organized differently. This Neuro Forum article offers an alternative explanation for their results and provides insights into motor memory processing in both experts and competents.

A multi-scale analysis of basketball throw in virtual reality for tracking perceptual-motor expertise

To benefit from virtual reality (VR) as a complementary tool for training, coaches must determine the proper tools and variables for tracking sports performance. We explored the basketball shooting at several scales (basket-ball, ball-player, and player systems) by monitoring success-rate, and ball and body kinematics. We measured how these scales of analysis allowed tracking players' expertise and perceptual sensitivity to basket distance. Experienced and novice players were instructed to naturally throw and swish an instrumented ball in a stereoscopically rendered virtual basket. We challenged their perceptual-motor systems by manipulating the distance of the virtual basket while keeping the surrounding environment unchanged. The success-rate accounted for the players' shooting adjustments to the manipulation of basket distance and allowed tracking their expertise. Ball kinematics also reflected the manipulation of distance and allowed detecting gender, but did not reflect the players' expertise. Finally, body kinematics variables did not echo players' adjustments to the distance manipulation but reflected their expertise and gender. The results gained at each scale of analysis are discussed with regard to the simulator's construct, biomechanical, and psychological fidelity.

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.

Learning different task spaces: how explored density aligns the Quiet Eye

In the current study, predictions of a theoretical account to the explanation of the Quiet Eye (QE) were investigated. To this end, by manipulating the learning environment, participants (n = 52) learned an underhand throwing task which required to explore task-solution spaces of low vs. high density over a 4-week training phase (640 training trials). Although throwing performance was improved, surprisingly, in posttest and retention test shorter QE durations were found. It is speculated that on a short-time learning scale this effect might be explained by more efficient information processing. Moreover, a trend was observed which suggests that—in line with the inhibition hypothesis—when exploring high-density task-solution spaces longer QE durations are required. However, the rather small effect sizes necessitate further research, which will allow to manipulate the response–effect mappings more directly as, for example, in virtual environments.

Neuroplasticity in Motor Learning Under Variable and Constant Practice Conditions-Protocol of Randomized Controlled Trial

Background

There is numerous literature on mechanisms underlying variability of practice advantages. Literature includes both behavioral and neuroimaging studies. Unfortunately, no studies are focusing on practice in constant conditions to the best of our knowledge. Hence it is essential to assess possible differences in mechanisms of neuroplasticity between constant vs. variable practice conditions. The primary objectives of the study described in this protocol will be: (1) to determine the brain's structural and functional changes following constant and variable practice conditions in motor learning (structural and functional magnetic resonance imaging, MRI); (2) to determine the EEG activation and connectivity between cognitive, sensory, and motor cerebral cortex areas (central, temporal, parietal, occipital) in constant and variable practice conditions and as a function of practice time.

Methods

The study will follow the interventional (experimental) design with two arms (parallel groups). Fifty participants will be randomly assigned to two groups practicing in constant (CG) and variable conditions (VG). CG will be practicing only one pattern of step isometric contractions during unimanual index finger abduction, i.e., 90 trials in all training sessions, whereas VG will practice three different patterns. Each will be practiced 30 times per session in variable conditions. Resting-state fMRI, EEG (cortical networking), and motor task proficiency will be examined before (pre-) and after practice (post- and retentions tests).

Discussion

Findings will enhance our understanding of structural and functional neural changes following practice in constant and variable conditions. Therefore, the study can be considered pure (basic) research (clinical research in healthy individuals).

Clinical Trial Registration

Study registered at clinicaltrials.gov (ID# NCT04921072) on 9 June 2021. Last version update: 21 December 2021.The protocol has been prepared according to the complete SPIRIT checklist (http://www.spirit-statement.org/), although the item order has been modified in order to comply with the manuscript structure.

Teaching Children's Motor Skills for Team Games Through Guided Discovery: How Constraints Enhance Learning

In this paper we examine the role of instructional strategies as constraints within a discovery learning framework for the teaching of open skill team ball games to elementary school-aged children. The cohesive and adaptive integration of constraints (individual, environment, and task) by practitioners of movement and physical activity (instructor, teacher, coach) is proposed as the pathway to exploiting the effectiveness of guided discovery learning. The qualitative analysis of the practical instantiations of this framework by expert teachers is examined with respect to the learning of open skill team invasion games (e.g., basketball, soccer). The primary constraints to action in this learning-teaching developmental framework are coordinated so as to keep the self-organization of skill development (movement pattern and tactics) continually evolving, while preserving the child's motivation and enjoyment for the expanding repertoire and performance capacity of his/her perceptual-motor skills. In this open skill and elementary school age-related context, generality and specificity are both necessary and complementary in the expression of task, skill and practice influences on motor learning and performance.

Investigating Different Levels of Bimanual Interaction With a Novel Motor Learning Task: A Behavioural and Transcranial Alternating Current Stimulation Study

Many tasks require the skilled interaction of both hands, such as eating with knife and fork or keyboard typing. However, our understanding of the behavioural and neurophysiological mechanisms underpinning bimanual motor learning is still sparse. Here, we aimed to address this by first characterising learning-related changes of different levels of bimanual interaction and second investigating how beta tACS modulates these learning-related changes. To explore early bimanual motor learning, we designed a novel bimanual motor learning task. In the task, a force grip device held in each hand (controlling x- and y-axis separately) was used to move a cursor along a path of streets at different angles (0°, 22.5°, 45°, 67.5°, and 90°). Each street corresponded to specific force ratios between hands, which resulted in different levels of hand interaction, i.e., unimanual (Uni, i.e., 0°, 90°), bimanual with equal force (Bi eq , 45°), and bimanual with unequal force (Bi uneq 22.5°, 67.5°). In experiment 1, 40 healthy participants performed the task for 45 min with a minimum of 100 trials. We found that the novel task induced improvements in movement time and error, with no trade-off between movement time and error, and with distinct patterns for the three levels of bimanual interaction. In experiment 2, we performed a between-subjects, double-blind study in 54 healthy participants to explore the effect of phase synchrony between both sensorimotor cortices using tACS at the individual's beta peak frequency. The individual's beta peak frequency was quantified using electroencephalography. 20 min of 2 mA peak-to-peak amplitude tACS was applied during task performance (40 min). Participants either received in-phase (0° phase shift), out-of-phase (90° phase shift), or sham (3 s of stimulation) tACS. We replicated the behavioural results of experiment 1, however, beta tACS did not modulate motor learning. Overall, the novel bimanual motor task allows to characterise bimanual motor learning with different levels of bimanual interaction. This should pave the way for future neuroimaging studies to further investigate the underlying mechanism of bimanual motor learning.

Critical Period After Stroke Study (CPASS): A phase II clinical trial testing an optimal time for motor recovery after stroke in humans

Restoration of postinjury brain function is a signal neuroscience challenge. Animal models of stroke recovery demonstrate time-limited windows of heightened motor recovery, similar to developmental neuroplasticity. However, no equivalent windows have been demonstrated in humans. We report a randomized controlled trial applying essential elements of animal motor training paradigms to humans, to determine the existence of an analogous sensitive period in adults. We found a similar sensitive or optimal period 60 to 90 d after stroke, with lesser effects ≤30 d and no effect 6 mo or later after stroke. These findings prospectively demonstrated the existence of a sensitive period in adult humans. We urge the provision of more intensive motor rehabilitation within 60 to 90 d after stroke onset.

Restoration of human brain function after injury is a signal challenge for translational neuroscience. Rodent stroke recovery studies identify an optimal or sensitive period for intensive motor training after stroke: near-full recovery is attained if task-specific motor training occurs during this sensitive window. We extended these findings to adult humans with stroke in a randomized controlled trial applying the essential elements of rodent motor training paradigms to humans. Stroke patients were adaptively randomized to begin 20 extra hours of self-selected, task-specific motor therapy at ≤30 d (acute), 2 to 3 mo (subacute), or ≥6 mo (chronic) after stroke, compared with controls receiving standard motor rehabilitation. Upper extremity (UE) impairment assessed by the Action Research Arm Test (ARAT) was measured at up to five time points. The primary outcome measure was ARAT recovery over 1 y after stroke. By 1 y we found significantly increased UE motor function in the subacute group compared with controls (ARAT difference = +6.87 ± 2.63, P = 0.009). The acute group compared with controls showed smaller but significant improvement (ARAT difference = +5.25 ± 2.59 points, P = 0.043). The chronic group showed no significant improvement compared with controls (ARAT = +2.41 ± 2.25, P = 0.29). Thus task-specific motor intervention was most effective within the first 2 to 3 mo after stroke. The similarity to rodent model treatment outcomes suggests that other rodent findings may be translatable to human brain recovery. These results provide empirical evidence of a sensitive period for motor recovery in humans.

The Effects of Manipulating Task Difficulty and Feedback Frequency on Children's Dart Throwing Accuracy and Consistency

In the present study we investigated the effects of manipulating task difficulty (constant vs. progressive difficulty) and frequency of knowledge of results (KR) on the accuracy and consistency of children's performance of a novel fine motor coordination task (dart throwing). We assigned 69 right-handed physical education (PE) students (M age = 10.73, SD = 0.89 years) to progressive (PDG) or constant difficulty (CDG) groups. PDG and CDG were each split into three subgroups who received varying KR frequency (100%KR, 50%KR, and 33%KR), creating a total of six groups. We increased difficulty in the PDG by manipulating the distance to the target (2 m, 2.37 m, and 3.56 m), while distance to the target was constant for CDG throughout the experiment (2.37 m). We conducted performance assessments during familiarization (pre-test), acquisition (post-test), and retention (retention testing) learning phases under both normal condition (NC) and a time pressure condition (TPC). Repeated-measures analysis of variance revealed a significant effect of difficulty manipulation on skill learning under both NC and TPC. Further analyses revealed that skill learning was enhanced by progressive difficulty manipulation. However, learning was not affected by KR frequency changes. Progressive difficulty practice enhanced both accuracy and consistency, specifically at retention testing. These results suggest that motor learning in children may be enhanced by practicing with progressive increases in difficulty. PE teachers are encouraged to gradually introduce difficulty levels in motor learning tasks that require high accuracy.

Mechanics of the Jump Shot: The "Dip" Increases the Accuracy of Elite Basketball Shooters

The present study assessed the mechanics of the basketball jump shot to determine whether or not the “dip” increased shot accuracy. There remained a debate between coaches who believed “dipping” was too slow and coaches who believed “dipping” increased accuracy. A mixed design was used for the present study with elite high-school and university players all performing shots with and without the “dip” at four distances: the last hash mark before the free throw line (3.125 m), the length of an imaginary hash mark beyond the free throw line (4.925 m), the top of the free throw circle (6.025 m), and the three-point line (6.750 m). These distances best emulated where the majority of shots were attempted in a game. Thirty-six athletes completed the study, with accuracy and shot quality being measured using Hardy-Parfitt’s six-point scale. The results of the present study indicated that the “dip” led to approximately a 7–9% increase in accuracy of the jump shot for both high school shooters, and university shooters, suggesting that coaches should begin to teach the “dip” in a player’s shooting motion to improve scoring results.

The effect of context variability on motor learning

Although the practice schedule and variation in incidental context have been investigated together, it is not clear whether just variation in incidental context can beneficiate motor learning. Therefore, the present study aimed to investigate the effect of context variability on motor learning. We hypothesized the practice in a variable incidental context would enable learners to be more resistant to the effects of the contextual changes when compared to a constant incidental context practice. Twenty-four participants were assigned to one of the two groups: constant incidental context (G_CC) or variable incidental context (G_VC). During practice, the G_CC practiced a sequence keypressing task in one color and a position showed on the computer screen. The G_VC practiced the same sequence in four different combinations of color and position. Twenty four hours, the same contexts practiced on practice (SAME) was performed and immediately after, a new sequential movement in new color and new position (SWITCH) was performed. The results indicated that the G_VC showed better performance than the G_CC on the SWITCH condition, mainly in measures related to planning/selection process. The results were explained by degree of similarity among processing events engaged during different moments and by development of a filter of information based on attentional selection.

Differences in Balance Ability and Motor Control between Dancers and Non-Dancers with Varying Foot Positions

The purpose of this study was to investigate balance and motor control in dancers and non-dancers with different foot positions. Physically active female dancers (n = 11) and non-dancers (n = 9) randomly completed two balance tests in a single visit: 1) Y-balance test (YBT), and 2) motor control test (MCT). Each test was completed with two different foot positions: 1) first ballet position in which heels were touching and feet were externally rotated to 140 degrees, and 2) sixth ballet position in which heels were spaced 10 cm apart and forward parallel. For the YBT, participants completed three attempts at anterior, posteromedial, and posterolateral reaches, which were averaged and standardized to limb length for a composite score. For the MCT, participants completed a multi-directional target test on a Biosway balance system, and accuracy and time to completion were analyzed. Findings revealed no differences in YBT score (p = 0.255), MCT score (p = 0.383), or MCT time (p = 0.306) between groups in the sixth position. However, dancers displayed better YBT scores (p = 0.036), MCT scores (p = 0.020), and faster MCT times (p = 0.009) in the first position. Results suggest that superior balance and motor control in dancers may be limited to less innate dance-specific foot positions.

Practice Motions Performed During Preperformance Preparation Drive the Actual Motion of Golf Putting

Of the various types of preperformance preparatory behavior that are acquired during motor learning, the effect of a practice motion performed just prior to execution of an actual motion is not yet fully understood. Thus, the present study employed a golf putting task to investigate how a practice motion in the preparation phase would affect the accuracy of motor control in the execution phase and how proficiency would influence this relationship. To examine the impacts on kinematics and final ball position, the velocities of practice strokes made by tour professional and amateur golfers were experimentally manipulated in the following three conditions: the equal condition, which presented a target that was at the same distance during the practice strokes and the actual stroke; the confusing condition, which had two different distances during the practice and actual strokes; and the no condition, which did not include a practice stroke. The results, based on final ball position, indicated that practice strokes in the equal condition were linked with the highest accuracy levels during the actual stroke in both professionals and amateurs. In the confusing condition, regardless of skill level, the velocity of the actual stroke was influenced by a faster or slower stroke during the pre-shot phase. These relationships between the practice and actual strokes imply that the golfers effectively utilized kinesthetic information obtained during the practice strokes as a reference for the actual stroke. Furthermore, the differences in proficiency level indicated that the club head velocity of amateurs in the no condition was significantly faster than in the equal condition. Therefore, the present results imply that the role of a practice stroke may differ between professionals and amateurs.

Principles of Neurorehabilitation After Stroke Based on Motor Learning and Brain Plasticity Mechanisms

What are the principles underlying effective neurorehabilitation? The aim of neurorehabilitation is to exploit interventions based on human and animal studies about learning and adaptation, as well as to show that the activation of experience-dependent neuronal plasticity augments functional recovery after stroke. Instead of teaching compensatory strategies that do not reduce impairment but allow the patient to return home as soon as possible, functional recovery might be more sustainable as it ensures a long-term reduction in impairment and an improvement in quality of life. At the same time, neurorehabilitation permits the scientific community to collect valuable data, which allows inferring about the principles of brain organization. Hence neuroscience sheds light on the mechanisms of learning new functions or relearning lost ones. However, current rehabilitation methods lack the exact operationalization of evidence gained from skill learning literature, leading to an urgent need to bridge motor learning theory and present clinical work in order to identify a set of ingredients and practical applications that could guide future interventions. This work aims to unify the neuroscientific literature relevant to the recovery process and rehabilitation practice in order to provide a synthesis of the principles that constitute an effective neurorehabilitation approach. Previous attempts to achieve this goal either focused on a subset of principles or did not link clinical application to the principles of motor learning and recovery. We identified 15 principles of motor learning based on existing literature: massed practice, spaced practice, dosage, task-specific practice, goal-oriented practice, variable practice, increasing difficulty, multisensory stimulation, rhythmic cueing, explicit feedback/knowledge of results, implicit feedback/knowledge of performance, modulate effector selection, action observation/embodied practice, motor imagery, and social interaction. We comment on trials that successfully implemented these principles and report evidence from experiments with healthy individuals as well as clinical work.

The Development of Generalized Motor Program in Constant and Variable Practice Conditions

The main objective of our study was to determine whether constant and variable practice conditions lead to the development of different memory representations (GMP) and as a result, they benefit performance of a skill differently. We compared one of the Generalized Motor Program (GMP) invariant features, i.e., relative timing, of the same variation of skill developed in constant and variable practice conditions. In two experiments, participants, naïve to the basketball, were practicing free throws, receiving the same amount of practice. In constant conditions they practiced at one distance only (4.57 m), whereas in variable conditions they practiced at seven (2.74, 3.35, 3.96, 4.57, 5.18, 5.79, and 6.4 m) and five (3.35, 3.96, 4.57, 5.18, and 5.79 m) distances, in Experiments 1 and 2, respectively. We found that relative timing of skills developed in constant and variable practice conditions is the same, confirming that these practice conditions form the same memory representation. However, we also observed that constant practice (CP) conditions resulted in overall shorter movement time as compared to the skill practiced in variable conditions. We hypothesized that it may be due to the facilitation of parameters assignment as it takes place in especial skill.

Gaze Behavior in Basketball Free Throws Developed in Constant and Variable Practice

There are a limited number of studies focusing on the mechanisms explaining why variable practice gives an advantage in a novel situation and constant practice in performance in trained conditions. We hypothesized that this may be due to the different gaze behavior that is developed under different conditions. Twenty participants, randomly assigned to two different groups, practiced basketball free throws for three consecutive days, performing 100 throws per day. The constant group (n = 10) practiced at a free throw distance (4.57 m) only. The variable practice group (n = 10) randomly performed 20 shots per five throw distances (3.35, 3.96, 4.57, 5.18, and 5.79 m) on each day, also accumulating 100 shots per day. We analyzed the total gaze fixation duration, a number of fixations, and the average fixation duration on a basketball rim in a pretest and posttest at the 4.57 m distance. We computed a linear mixed model with test (pretest–posttest), group (constant–variable), and test × group interaction in order to analyze the total fixation duration and number of fixations. The average fixation duration was analyzed with a repeated measure two-way ANOVA, with practice conditions as a between-participants factor and test type as a within-participants factor. We found that the total fixation duration increased significantly in the posttest, regardless of the practice conditions (p < 0.001, effect size = 0.504). The number of fixations also increased significantly in the posttest (p = 0.037, effect size = 0.246). The average fixation duration increased in both groups; however, insignificantly. We also did not find any significant differences between groups. Our results suggest that variable and constant practice conditions may lead to the development of similar gaze behavior.

The Quiet Eye and Motor Expertise: Explaining the "Efficiency Paradox"

It has been consistently reported that experts show longer quiet eye (QE) durations when compared to near-experts and novices. However, this finding is rather paradoxical as motor expertise is characterized by an economization of motor-control processes rather than by a prolongation in response programming, a suggested explanatory mechanism of the QE phenomenon. Therefore, an inhibition hypothesis was proposed that suggests an inhibition of non-optimal task solutions over movement parametrization, which is particularly necessary in experts due to the great extent and high density of their experienced task-solution space. In the current study, the effect of the task-solution space' extension was tested by comparing the QE-duration gains in groups that trained a far-aiming task with a small number (low-extent) vs. a large number (high-extent) of task variants. After an extensive training period of more than 750 trials, both groups showed superior performance in post-test and retention test when compared to pretest and longer QE durations in post-test when compared to pretest. However, the QE durations dropped to baseline values at retention. Finally, the expected additional gain in QE duration for the high-extent group was not found and thus, the assumption of long QE durations due to an extended task-solution space was not confirmed. The findings were (by tendency) more in line with the density explanation of the inhibition hypothesis. This density argument suits research revealing a high specificity of motor skills in experts thus providing worthwhile options for future research on the paradoxical relation between the QE and motor expertise.

Investigation of Perceptual-Motor Behavior Across the Expert Athlete to Disabled Patient Skill Continuum can Advance Theory and Practical Application

A framework is presented of how theoretical predictions can be tested across the expert athlete to disabled patient skill continuum. Common-coding theory is used as the exemplar to discuss sensory and motor system contributions to perceptual-motor behavior. Behavioral and neural studies investigating expert athletes and patients recovering from cerebral stroke are reviewed. They provide evidence of bi-directional contributions of visual and motor systems to perceptual-motor behavior. Majority of this research is focused on perceptual-motor performance or learning, with less on transfer. The field is ripe for research designed to test theoretical predictions across the expert athlete to disabled patient skill continuum. Our view has implications for theory and practice in sports science, physical education, and rehabilitation.

Role of Constant, Random and Blocked Practice in an Electromyography-Based Oral Motor Learning Task

PURPOSE

The role of principles of motor learning (PMLs) in speech has received much attention in the past decade. Oral motor learning, however, has not received similar consideration. This study evaluated the role of three practice conditions in an oral motor tracking task.

METHOD

Forty-five healthy adult participants were randomly and equally assigned to one of three practice conditions (constant, blocked, and random) and participated in an electromyography-based task. The study consisted of four sessions, at one session a day for four consecutive days. The first three days sessions included a practice phase, with immediate visual feedback, and an immediate retention phase, without visual feedback. The fourth session did not include practice, but only delayed retention testing, lasting 10-15 minutes, without visual feedback.

RESULTS

Random group participants performed better than participants in constant and blocked practice conditions on all the four days. Constant group participants demonstrated superior learning over blocked group participants only on day 4.

CONCLUSION

Findings indicate that random practice facilitates oral motor learning, which is in line with limb/speech motor learning literature. Future research should systematically investigate the outcomes of random practice as a function of different oral and speech-based tasks.

Are young children able to learn exploratory strategies by observation?

New competencies may be learned through active experience (experiential learning or learning by doing) or observation of others' experiences (learning by observation). Observing another person performing a complex action facilitates the observer's acquisition of the same action. The present research is aimed at analyzing if the observation of specific explorative strategies adopted in a constrained environment, such as the Radial Arm Maze (RAM), could help young children to explore the maze and to build a cognitive spatial map of the explored environment. To this aim young children were randomly assigned to three groups: children who performed the RAM task following the observation of an actor solving the same maze by putting into action a highly structured exploratory strategy; children who performed the RAM task following the observation of the actor solving the same maze by putting into action a less structured exploratory strategy; children who directly performed the RAM task without any observation. The main result of the present research is that the children who observed the highly structured and correct exploratory strategy spent less time, made fewer errors, exhibited a longer spatial span, and thus they explored the maze more efficiently than the children who directly performed the RAM task without any observation. This finding indicates that when the observed explorative procedure is structured, sequential and repetitive the action understanding and information storage processes are more effective. Importantly, the observation of specific spatial strategies helped the children to build the cognitive spatial map of the explored environment and consequently to acquire/enrich the declarative knowledge of the environment.

Specificity vs. Generalizability: Emergence of Especial Skills in Classical Archery

There is evidence that the recall schema becomes more refined after constant practice. It is also believed that massive amounts of constant practice eventually leads to the emergence of especial skills, i.e., skills that have an advantage in performance over other actions from within the same class of actions. This advantage in performance was noticed when one-criterion practice, e.g., basketball free throws, was compared to non-practiced variations of the skill. However, there is no evidence whether multi-criterion massive amounts of practice would give an advantage to the trained variations of the skill over non-trained, i.e., whether such practice would eventually lead to the development of (multi)-especial skills. The purpose of this study was to determine whether massive amount of practice involving four criterion variations of the skill will give an advantage in performance to the criterions over the class of actions. In two experiments, we analyzed data from female (n = 8) and male classical archers (n = 10), who were required to shoot 30 shots from four accustomed distances, i.e., males at 30, 50, 70, and 90 m and females at 30, 50, 60, and 70 m. The shooting accuracy for the untrained distances (16 distances in men and 14 in women) was used to compile a regression line for distance over shooting accuracy. Regression determined (expected) values were then compared to the shooting accuracy of the trained distances. Data revealed no significant differences between real and expected results at trained distances, except for the 70 m shooting distance in men. The F-test for lack of fit showed that the regression computed for trained and non-trained shooting distances was linear. It can be concluded that especial skills emerge only after very specific practice, i.e., constant practice limited to only one variation of the skill.

Does skill specialisation influence individual differences in drag flicking speed and accuracy?

Research has revealed that individual soccer goalkeepers respond differently to penalty shots, depending on their specific perceptual and motor capabilities. However, it remains unclear whether analogous differences exist between individual penalty takers, and if specialising in penalty taking affects the occurrence of differences between individuals. The present study examined individual differences in penalty shot speed and accuracy for specialists in penalty taking versus non-specialists. Expert specialist field hockey drag flickers and equivalently skilled non-specialists performed drag flicks towards predetermined targets placed in the face of a standard field hockey goal. Comparisons in shot speed and accuracy were made at a group level (specialists vs. non-specialists) as well as between individuals. Results revealed differences in both speed and accuracy between specialists, but only differences in speed between non-specialists. Specialists generated significantly greater shot speed than non-specialists (P < .001) and were more accurate to some, but not all, targets (top left, P < .006, bottom left P < .001). In addition, it was found that in specialists increasing practice correlated with decreasing accuracy. This may indicate that excessive practice could potentially reduce a specialist's accuracy in shooting towards specific targets.

Specificity of foot configuration during bipedal stance in ballet dancers

BACKGROUND AND AIM

Learning highly specialized upright postures may be of benefit for more common as well as for novel stances. In this study, we asked whether this generalization occurs with foot configurations previously trained or depends on a generic increase in balance difficulty. We also explored the possibility that the benefit may concern not only the level of postural performance but also the structural organization of the upright standing.

METHODS

Ten elite professional ballet dancers were compared to ten untrained subjects, measuring the motion of the center of pressure (COP) across a set of five stances with different foot configurations. The balance stability was measured computing the area, the sway path, and the root mean square of the COP motion, whereas the structure of the postural control was assessed by compute approximate entropy, fractal dimension and the mean power frequency. The foot position included common and challenging stances, with the level of difficulty changed across the configurations. Among these conditions, only one foot configuration was familiar to the dancers.

RESULTS

Statistically significant differences between the two groups, for all the parameters, were observed only for the stance with the foot position familiar to the dancers. Stability and structural parameters exhibited comparable differences.

CONCLUSIONS

We concluded that the benefit from classical ballet is limited to a specific foot configuration, regardless of the level of stance difficulty or the component of postural control.

The fourth dimension: A motoric perspective on the anxiety-performance relationship

This article focuses on raising concern that anxiety-performance relationship theory has insufficiently catered for motoric issues during, primarily, closed and self-paced skill execution (e.g., long jump and javelin throw). Following a review of current theory, we address the under-consideration of motoric issues by extending the three-dimensional model put forward by Cheng, Hardy, and Markland (2009) ('Toward a three-dimensional conceptualization of performance anxiety: Rationale and initial measurement development, Psychology of Sport and Exercise, 10, 271-278). This fourth dimension, termed skill establishment, comprises the level and consistency of movement automaticity together with a performer's confidence in this specific process, as providing a degree of robustness against negative anxiety effects. To exemplify this motoric influence, we then offer insight regarding current theories' misrepresentation that a self-focus of attention toward an already well-learned skill always leads to a negative performance effect. In doing so, we draw upon applied literature to distinguish between positive and negative self-foci and suggest that on what and how a performer directs their attention is crucial to the interaction with skill establishment and, therefore, performance. Finally, implications for skill acquisition research are provided. Accordingly, we suggest a positive potential flow from applied/translational to fundamental/theory-generating research in sport which can serve to freshen and usefully redirect investigation into this long-considered but still insufficiently understood concept.

Progressive reduction versus fixed level of support during training: When less is less

Previous empirical and theoretical work suggests that effective skill acquisition requires movements to be generated actively and that learning new skills supports the acquisition of prospective control. However, there are many ways in which practice can be structured, that may affect the acquisition and use of prospective control after training. Here, we tested whether the progressive modulation and reduction of support during training was required to yield good performance after training without support. The task was to use a stylus to push a bead over a complex 3D wire path. The support "magnetically" attracted and held the stylus onto the wire. Three groups of adult participants each experienced one of three training regimes: gradual reduction of magnetic attraction, only a medium level of attraction, or low magnetic attraction. The results showed that use of a single (medium) level of support was significantly less effective in yielding good performance with low support after training. Training with low support yielded post-training performance that was equally good as that yielded by training with progressive reduction of support; however, performance during training was significantly poorer in the former. Thus, less support during training yields effective learning but more difficult training sessions. The results are discussed in the context of application to training with special populations.

Speech and swallow rehabilitation following partial glossectomy: a systematic review

PURPOSE

Tongue cancer is known to negatively affect both speech and swallowing function; however this is the first review to report speech-language pathology (SLP) intervention for both functions following partial glossectomy.

METHOD

Using a PRISMA approach, systematic screening of nine databases was undertaken. Original studies reporting SLP rehabilitation for speech and/or swallowing dysfunction with participants following partial glossectomy as primary cancer treatment were included.

RESULT

These studies are discussed in terms of SLP assessment and intervention trends as well as quality according to current research method standards (levels of evidence, Pedro-P, SCED) in order to determine suitability for guiding current clinical practice.

CONCLUSION

Publications were few (n = 7) and mostly of non-experimental design. This review highlights the gap in evidence and questions the rationale of current SLP rehabilitation following partial glossectomy.

The hot hand belief and framing effects

PURPOSE

Recent evidence of the hot hand in sport-where success breeds success in a positive recency of successful shots, for instance-indicates that this pattern does not actually exist. Yet the belief persists. We used 2 studies to explore the effects of framing on the hot hand belief in sport. We looked at the effect of sport experience and task on the perception of baseball pitch behavior as well as the hot hand belief and free-throw behavior in basketball.

METHOD

Study 1 asked participants to designate outcomes with different alternation rates as the result of baseball pitches or coin tosses. Study 2 examined basketball free-throw behavior and measured predicted success before each shot as well as general belief in the hot hand pattern.

RESULTS

The results of Study 1 illustrate that experience and stimulus alternation rates influence the perception of chance in human performance tasks. Study 2 shows that physically performing an act and making judgments are related. Specifically, beliefs were related to overall performance, with more successful shooters showing greater belief in the hot hand and greater predicted success for upcoming shots.

CONCLUSIONS

Both of these studies highlight that the hot hand belief is influenced by framing, which leads to instability and situational contingencies. We show the specific effects of framing using accumulated experience of the individual with the sport and knowledge of its structure and specific experience with sport actions (basketball shots) prior to judgments.

The learning of isometric force time scales is differentially influenced by constant and variable practice

This experiment was set up to investigate the influence of constant and variable practice on performance accuracy and the time- and frequency-dependent structure of the force output dynamics in the learning of an irregular isometric force pattern. Traditional approaches to the variability of practice hypothesis have demonstrated benefits of task-induced variability at the outcome level of behavior, but there have been limited investigations of the effect of practice conditions on movement execution and particularly the multiple time scale processes of force output. During the practice phase, variability was induced along the force-time dimension of the target pattern for the variable practice condition (different wave forms), but the wave forms exhibited the same distributional properties of the frequency content (1/f noise: β = -1.5) as the constant practice condition. The results showed that both practice conditions exhibited similar reductions in task error as a function of practice. However, constant practice produced greater changes in the time- and frequency-dependent properties of force output than variable practice, including a higher relative change in the contribution from faster (4-12 Hz) time scale mechanisms. Generalization tests to novel target patterns revealed that the task dynamics had a greater influence than the effect of practice conditions. Collectively, the findings support the adaptive nature of force output structure and the perspective that practice conditions can produce differential effects on the outcome and execution levels of motor behavior.

Interdisciplinary Comprehensive Arm Rehabilitation Evaluation (ICARE): a randomized controlled trial protocol

BACKGROUND

Residual disability after stroke is substantial; 65% of patients at 6 months are unable to incorporate the impaired upper extremity into daily activities. Task-oriented training programs are rapidly being adopted into clinical practice. In the absence of any consensus on the essential elements or dose of task-specific training, an urgent need exists for a well-designed trial to determine the effectiveness of a specific multidimensional task-based program governed by a comprehensive set of evidence-based principles. The Interdisciplinary Comprehensive Arm Rehabilitation Evaluation (ICARE) Stroke Initiative is a parallel group, three-arm, single blind, superiority randomized controlled trial of a theoretically-defensible, upper extremity rehabilitation program provided in the outpatient setting.The primary objective of ICARE is to determine if there is a greater improvement in arm and hand recovery one year after randomization in participants receiving a structured training program termed Accelerated Skill Acquisition Program (ASAP), compared to participants receiving usual and customary therapy of an equivalent dose (DEUCC). Two secondary objectives are to compare ASAP to a true (active monitoring only) usual and customary (UCC) therapy group and to compare DEUCC and UCC.

METHODS/DESIGN

Following baseline assessment, participants are randomized by site, stratified for stroke duration and motor severity. 360 adults will be randomized, 14 to 106 days following ischemic or hemorrhagic stroke onset, with mild to moderate upper extremity impairment, recruited at sites in Atlanta, Los Angeles and Washington, D.C. The Wolf Motor Function Test (WMFT) time score is the primary outcome at 1 year post-randomization. The Stroke Impact Scale (SIS) hand domain is a secondary outcome measure.The design includes concealed allocation during recruitment, screening and baseline, blinded outcome assessment and intention to treat analyses. Our primary hypothesis is that the improvement in log-transformed WMFT time will be greater for the ASAP than the DEUCC group. This pre-planned hypothesis will be tested at a significance level of 0.05.

DISCUSSION

ICARE will test whether ASAP is superior to the same number of hours of usual therapy. Pre-specified secondary analyses will test whether 30 hours of usual therapy is superior to current usual and customary therapy not controlled for dose.

TRIAL REGISTRATION

www.ClinicalTrials.gov Identifier: NCT00871715

Constant or variable practice: recreating the especial skill effect

An especial skill occurs when performance of a single action from within a class of actions produces an advantage in performance. This advantage in a single action over others in the class is presumed to result from large amounts of practice performing the specific action (Keetch, Schmidt, Lee, & Young, 2005). In an experiment involving the learning of a basketball set shot, practice was manipulated to identify whether an especial skill effect emerges at the free-throw line as a result of constant practice conditions in novice performers. After a pretest, which involved set shots across five distances, participants were randomly assigned to one of two intervention groups. A constant practice group (n=10) performed 300 trials of the set shot at the 15 ft free throw line only, whereas a variable practice group (n=10) performed 300 trials across five distances. Shot accuracy increased for both groups as a result of practice at the 15' distance. However, on the posttest, a significant difference was reported between actual and expected scores for the constant practice group only. This finding provided evidence that an effect similar to that seen for especial skills emerges as a result of constant practice. Although an especial skill effect could result from massive amounts of practice, we show it can emerge as a result of short term repetitive practice, indicating that the type, rather than amount, of practice is important.

Circle drawing does not exhibit auditory-motor synchronization

Differences in timing control processes between tapping and circle drawing have been extensively documented during continuation timing. Differences between event and emergent control processes have also been documented for synchronization timing using emergent tasks that have minimal event-related information. However, it is not known whether the original circle-drawing task also behaves differently than tapping during synchronization. In this experiment, 10 participants performed a table-tapping and a continuous circle-drawing task to an auditory metronome. Synchronization performance was assessed via the value and variability of asynchronies. Synchronization was substantially more difficult in circle drawing than in tapping. Participants drawing timed circles exhibited drift in synchronization error and did not maintain a consistent phase relationship with the metronome. An analysis of temporal anchoring revealed that timing to the timing target was not more accurate than timing to other locations on the circle trajectory. The authors conclude that participants were not able to synchronize movement with metronome tones in the circle-drawing task despite other findings that cyclical tasks do exhibit auditory motor synchronization, because the circle-drawing task is unique and absent of event and cycle position information.

From Intention to Input: Motor Cognition, Motor Performance, and the Control of Technology

Fundamental knowledge of motor cognition is an important component in a human factors repertoire, and this chapter serves as a guide to the history, theory, and application of motor cognition research.“From intention to input” captures the scope of this chapter in that cognitive theories of motor control, neural control of movement, and the effects of feedback on movement are all discussed. The chapter progresses from an overview and history of motor cognition theories down to the neural basis for movement, then to an application of these theories via the study of specific actions. From there, rooted in the scientist-practitioner paradigm of human factors, the chapter covers applied considerations for designing control tasks and their associated inputs, taking into account individual differences in motor cognition and control and identifying critical issues in designing for input. General, applied guidelines are provided for use with current and future systems that have a motor cognition component.

Motor schema development in constant practice: the gradient in bimanual juggling with three balls

Motor schemas are very attractive concepts; however, their development and internal structure appear difficult to probe and identify. The present study focuses on the development of a motor schema in constant practice. In four experiments, participants practiced bimanual juggling with three standard balls. During retention tests they were asked to juggle with standard ("practiced") balls and nonstandard ("nonpracticed") balls of different weight, shape, length, and size. Four juggling experiments were carried out. The participants achieved the best results juggling with the practiced balls in three experiments. During one experiment, they achieved better results juggling with nonpracticed balls. However, in all four experiments, a correlation was observed between the number of correct juggling sequences with standard balls and with nonpracticed balls. Scores presented as mean numbers of juggling cycles performed in retention tests revealed a gradient with its peak value for juggling with the practiced balls. In one experiment, the hypothetical gradient slope was steeper; however, a strong correlation between scores for juggling with practiced and nonpracticed balls was noted.

Specificity and variability of practice, and contextual interference in acquisition and transfer of an underhand volleyball serve

The present study investigated the effects of practice composition on acquisition and transfer of the underhand volleyball serve in a standard high school physical education setting. 72 middle-school students (M age = 14.1 yr., SD = 0.7) were selected and assigned to six groups: five experimental (Random, Serial, Blocked, Constant, Specific), and one Control group all pretested. The five experimental groups received 45 acquisition trials over three class periods. Directional quantitative knowledge of results was provided to the students after each trial. After a 72-hr. retention interval, all groups performed 15 underhand volleyball serves without knowledge of results. Analyses indicated (a) better acquisition in the Specific and Constant groups relative to the Serial, Random, and Blocked groups, and (b) significantly superior transfer performance in the Specific and Random groups relative to the Serial, Blocked, Constant, and Control groups. This provides partial support for specificity of learning and contextual interference hypotheses. Practice in accord with the contextual interference hypothesis permits differentiations among varied practice schedules only during transfer.

Circumstances under which practice does not make perfect: a review of the practice effect literature in schizophrenia and its relevance to clinical treatment studies

In this article, we review the literature on practice effects in schizophrenia, an underappreciated confound in interpreting cognitive improvement in clinical trials. We first examine claims regarding first- and second-generation antipsychotic medications as cognitive enhancers, and follow it with a discussion of recent studies demonstrating how practice or placebo effects may drive 'positive' findings. Thus, this review suggests that many previous findings can be reinterpreted in this light. Critically, we also make several suggestions about test construction, study design, and statistical analyses that the field might use to overcome this potential confound. Our suggestions may also have implications for drug discovery and regulatory approval of cognitive-enhancing adjunctive agents, in terms of study design and/or test psychometric characteristics, including the development of tests that are relatively insensitive to practice-related changes. Such advances might be important for improving the methodology involved in the assessment of cognitive change in treatment studies.

Challenges to cognitive bases for an especial motor skill at the regulation baseball pitching distance

We tested expert baseball pitchers for evidence of especial skills at the regulation pitching distance. Seven college pitchers threw indoors to a target placed at 60.5 feet (18.44 m) and four closer and four further distances away. Accuracy at the regulation distance was significantly better than predicted by regression on the nonregulation distances (p < .02), indicating an especial skill effect emerged despite the absence of normal contextual cues. Self-efficacy data failed to support confidence as a mediating factor in especial skill effect. We concluded that cognitive theories fail to fully account for the patterns of observed data, and therefore theoretical explanations of the especial skills must address noncognitive aspects of motor learning and control.