Chapter 1 The Rise and Fall of Dominant Paradigms in Motor Behaviour Research

Synergies in coordination: a comprehensive overview of neural, computational, and behavioral approaches

At face value, the term "synergy" provides a unifying concept within a fractured field that encompasses complementary neural, computational, and behavioral approaches. However, the term is not used synonymously by different researchers but has substantially different meanings depending on the research approach. With so many operational definitions for the one term, it becomes difficult to use as either a descriptive or explanatory concept, yet it remains pervasive and apparently indispensable. Here we provide a summary of different approaches that invoke synergies in a descriptive or explanatory context, summarizing progress, not within the one approach, but across the theoretical landscape. Bernstein's framework of flexible hierarchical control may provide a unifying framework here, since it can incorporate divergent ideas about synergies. In the current motor control literature, synergy may refer to conceptually different processes that could potentially operate in parallel, across different levels within the same hierarchical control scheme. There is evidence for the concurrent existence of synergies with different features, both "hard-wired" and "soft-wired," and task independent and task dependent. By providing a comprehensive overview of the multifaceted ideas about synergies, our goal is to move away from the compartmentalization and narrow the focus on one level and promote a broader perspective on the control and coordination of movement.

Identification of Underlying Assumptions is an Integral Part of Research: An Example from Motor Control

Research is inherently subjective. It is conducted within a theoretical and methodological framework, the validity of which depends on underlying assumptions about the nature of reality and knowledge. The interpretation of one's own data, and the evaluation of the data interpretation of others, requires assessment of these underlying philosophical assumptions. We contend that while examination of philosophical assumptions is demonstrably an integral part of research, it is one which has largely been neglected in experimental psychology because researchers have rarely explicitly identified their ontological and epistemological assumptions. A contemporary debate in experimental psychology, that between representational and non-representational approaches to understanding the control of movement, is discussed to illustrate the influence such ontological and epistemological assumptions have upon methodological choices and upon the development and evaluation of theory.

Effects of an Occupation-Based Intervention on Mobility Problems Following a Cerebral Vascular Accident

The usefulness of a new occupational therapy approach to intervention was explored with three individuals who had sustained a cerebral vascular accident (CVA). This new approach, the Occupational Adaptation Frame of Reference (OA), was used to guide the occupational therapist in the treatment of mobility problems associated with the CVA. Participants were assessed and treated by an occupational therapist in their home environment. Three case studies were compiled from qualitative and quantitative data. Data were gathered through observation, videotaping, narrative stories, and the Movement Rating Scale. Results revealed that intervention based on OA was associated with improved mobility skills.

Placing the Perceptual-Cognitive Approach in Perspective

Although some features of the "psychological approach" are compelling, its immediate impact as a theoretical framework appears to be limited by somewhat ambiguous key constructs and the lack of appropriate placement vis-a-vis extant conceptual views.

Difference-based meta-analytic procedures for between-participant and/or within-participant designs: a tutorial review for sports and exercise scientists

The aim of this paper is to provide a contemporary summary of statistical and non-statistical meta-analytic procedures that have relevance to the type of experimental designs often used by sport scientists when examining differences/change in dependent measure(s) as a result of one or more independent manipulation(s). Using worked examples from studies on observational learning in the motor behaviour literature, we adopt a random effects model and give a detailed explanation of the statistical procedures for the three types of raw score difference-based analyses applicable to between-participant, within-participant, and mixed-participant designs. Major merits and concerns associated with these quantitative procedures are identified and agreed methods are reported for minimizing biased outcomes, such as those for dealing with multiple dependent measures from single studies, design variation across studies, different metrics (i.e., raw scores and difference scores), and variations in sample size. To complement the worked examples, we summarize the general considerations required when conducting and reporting a meta-analysis, including how to deal with publication bias, what information to present regarding the primary studies, and approaches for dealing with outliers. By bringing together these statistical and non-statistical meta-analytic procedures, we provide the tools required to clarify understanding of key concepts and principles.

Dominant Paradigms in Motor Behavior Research: The Motor-Action Controversy Revisited

In 1992, Abernethy and Sparrow published an evaluation of the historical development of the field of motor behavior research as published from 1977 up to 1988 in the Journal of Motor Behavior. The present study extends their evaluation from 1988 through 2005 using content analyses of articles on motor control and learning in this journal. Papers were categorized into the two dominant and contrasting paradigms, the motor systems approach and the action systems approach. Analysis suggests that the field of motor behavior research has changed considerably over the last three decades. The action systems approach is now the leading approach, but the motor systems approach has, however, not perished. In a Kuhnian perspective, the results might be consistent with a more long-lasting crisis, and from the available data it is not possible to predict a future outcome of the dispute between the two approaches.

An overview of adaptive model theory: solving the problems of redundancy, resources, and nonlinear interactions in human movement control

Adaptive model theory (AMT) is a computational theory that addresses the difficult control problem posed by the musculoskeletal system in interaction with the environment. It proposes that the nervous system creates motor maps and task-dependent synergies to solve the problems of redundancy and limited central resources. These lead to the adaptive formation of task-dependent feedback/feedforward controllers able to generate stable, noninteractive control and render nonlinear interactions unobservable in sensory-motor relationships. AMT offers a unified account of how the nervous system might achieve these solutions by forming internal models. This is presented as the design of a simulator consisting of neural adaptive filters based on cerebellar circuitry. It incorporates a new network module that adaptively models (in real time) nonlinear relationships between inputs with changing and uncertain spectral and amplitude probability density functions as is the case for sensory and motor signals.

Effects of a functional therapy program on motor abilities of children with cerebral palsy

BACKGROUND AND PURPOSE

The purpose of this study was to determine whether the motor abilities of children with spastic cerebral palsy who were receiving functional physical therapy (physical therapy with an emphasis on practicing functional activities) improved more than the motor abilities of children in a reference group whose physical therapy was based on the principle of normalization of the quality of movement.

SUBJECTS

The subjects were 55 children with mild or moderate cerebral palsy aged 2 to 7 years (median=55 months).

METHODS

A randomized block design was used to assign the children to the 2 groups. After a pretest, the physical therapists for the functional physical therapy group received training in the systematic application of functional physical therapy. There were 3 follow-up assessments: 6, 12, and 18 months after the pretest. Both basic gross motor abilities and motor abilities in daily situations were studied, using the Gross Motor Function Measure (GMFM) and the self-care and mobility domains of the Pediatric Evaluation of Disability Inventory (PEDI), respectively.

RESULTS

Both groups had improved GMFM and PEDI scores after treatment. No time x group interactions were found on the GMFM. For the PEDI, time x group interactions were found for the functional skills and caregiver assistance scales in both the self-care and mobility domains.

DISCUSSION AND CONCLUSION

The groups' improvements in basic gross motor abilities, as measured by the GMFM in a standardized environment, did not differ. When examining functional skills in daily situations, as measured by the PEDI, children in the functional physical therapy group improved more than children in the reference group.

Skill acquisition in sport: some applications of an evolving practice ecology

This paper builds on recent theoretical concerns regarding traditional conceptualizations of the skill acquisition process. The implications for the process of practice in sport contexts are explored with reference to the information-processing approach to motor behaviour and the newer ecological paradigm. Issues are raised with current principles of practice based on traditional theoretical ideas. A practice strategy that gives greater weight to the guided exploration of the practice workspace jointly defined by the properties of the individual's subsystems, the specific task and the environment is advocated. Such a constraints-led perspective supersedes previous distinctions between rudimentary and voluntary skills. Sports scientists, coaches, teachers and movement rehabilitation therapists are invited to review current practices in the light of recent theoretical advances from the ecological perspective.

Transfer to changed serial position in a task of tracking a sequence of light stimuli

This study examined transfer when different serial positions are changed in a task of tracking a sequence of light stimuli. Thirty subjects were divided into three groups, and all tracked a serial pattern of six movements for 20 acquisition trials. Then, on 20 more transfer trials, the last two movements were reversed for Group I, the second two movements reversed for Group II, and the first two movements reversed for the Group III. Performance during the transfer trials improved over performance during the acquisition trials for Groups I and II but not Group III. Thus, there appeared to be positive transfer when the last and middle parts of the serial pattern were changed. However, there was no positive transfer when the first part of the serial pattern was changed. This indicated a contextual interference effect dependent upon serial position in the performance of a serial tracking task.

Development of cursive handwriting

The efficiency of two different instructional methods for improving the growth of handwriting quality in the upper grades of primary school was investigated in field experiments using a control-group design. No improvement in mean quality was found for a group of 38 children using a method based on copying exercises. A substantial improvement in mean quality, corresponding to about 1.4 SD, was found for 23 children using a method based on reintroduction of the letter forms explaining each form visually and verbally. It was concluded that the bottleneck in the development of handwriting quality in primary school is a mismatch between the instructional methods used and the perceptual ability of the children.

Asymmetries in Coupling Dynamics of Perception and Action

The influence of information-based dynamics on coordination dynamics of rhythmic movement was examined with special reference to the expression of asymmetries. In Experiment 1, right-handed subjects performed unimanual, rhythmical movements in coordination with either a discrete or continuous visual display. The right hand-visual display system defined a more stable perception-action collective than the left, particularly when continuous visual information was available. In Experiment 2, the same subjects performed rhythmic bimanual movements in coordination with a continuous visual display. The action collective was inherently more stable than the perception-action collective, although similar patterns were observed at both levels. Importantly, the dynamics of the perception-action collective impinged upon the dynamics of the action collective in terms of stability. Asymmetries remained evident between limbs in the bimanual preparations, with the left hand exhibiting greater limit-cycle variability and also a tendency to more often effect transitions at the action couple. Features of dynamical models that capture characteristics of manual asymmetries are discussed.

The natural physical alternative to cognitive theories of motor behaviour: an invitation for interdisciplinary research in sports science?

This review examines the viability of the natural physical alternative to traditional cognitive modelling of the sport performer. It is concluded that the natural physical perspective offers an attractive framework for the study of movement control and co-ordination in sport, but, at present, does not seem capable of superseding cognitive explanations. As a consequence of the nature of the questions they are asking, natural physical theorists offer a significant avenue for interdisciplinary research in sports science. Significant differences in the philosophy underpinning both theoretical views are acknowledged, but growing support for an integrated approach to motor control is highlighted. A major task for sports scientists may be to verify empirically the nature of an integrated model of the sport performer.

Structural constraints on bimanual movements

A theoretical framework is outlined, according to which structural constraints on bimanual movements can at least in part be understood as coupling between parameters of generalized motor programs. This framework provides a conceptual link between reaction-time data from experiments with bimanual responses, successive unimanual responses, and choice between left-hand and right-hand responses on the one hand and performance data obtained with concurrently performed continuous movements or sequences of discrete responses on the other. On the basis of data obtained with different methods for the study of intermanual interactions, a distinction is drawn between steady-state and transient constraints, and the hypothesis that the tendency to coactivate homologous muscles originates from a transient coupling of program parameters is applied to a variety of observations on performance in different tasks. Finally, the notion of transient constraints is applied to other types of intermanual interdependencies, and to interpersonal coordination; the possible emergence of transient constraints from steady-state constraints through progressive development of inhibitory pathways in childhood is discussed, as is the potential biological significance of transient constraints.

Searching for the minimal essential information for skilled perception and action

A common concern for both cognitive/computational and ecological/dynamical models of human motor control is the isolation of the minimal essential information needed to support skilled perception and action. In perception isolating essential features of the optic flow field, which are reliably informative regarding the nature of current events, from nonessential features provides a valuable step towards understanding how the computational complexity of perceptual information processing may be reduced to manageable levels and how relatively direct linkages of low dimensionality may be established between information and control variables. Likewise, in the study of action, discrimination of the movement features that remain immutable (invariant?) across changes in task conditions from the variables that are situationally determined provides a principle insight into the structural framework upon which skilled movement is built. Controversy abounds, however, in the study of perception and action as to whether features isolated as informative and immutable are centrally represented (in the form of a template or program) or are rather directly picked up (in the case of perceptual variables) or are simply an emergent consequence of the underlying dynamics (in the case of action variables). In this paper some examples of putative minimal essential information sources in perception and action are provided, strategies for uncovering such sources are discussed, and attention is directed, with the use of some recent data collected on natural skills, to some systematic expert-novice differences in the utilization of essential information and control variables. Expert-novice differences are highlighted because of the insight they may provide regarding the nature of perceptual-motor skill acquisition.