Perceptual-motor regulation in locomotor pointing while approaching a curb

Locomotor pointing is a task that has been the focus of research in the context of sport (e.g. long jumping and cricket) as well as normal walking. Collectively, these studies have produced abroad understanding of locomotor pointing, but generalizability has been limited to laboratory type tasks and/or tasks with high spatial demands. The current study aimed to generalize previous findings in locomotor pointing to the common daily task of approaching and stepping on to a curb. Sixteen people completed 33 repetitions of a task that required them to walk up to and step onto a curb. Information about their foot placement was collected using a combination of measures derived from a pressure-sensitive walkway and video data. Variables related to perceptual-motor regulation were analyzed on an inter-trial, intra-step and inter-step level. Similar to previous studies, analysis of the foot placements showed that, variability in foot placement decreased as the participants drew closer to the curb. Regulation seemed to be initiated earlier in this study compared to previous studies, as shown by a decreasing variability in foot placement as early as eight steps before reaching the curb. Furthermore, it was shown that when walking up to the curb, most people regulated their walk in a way so as to achieve minimal variability in the foot placement on top of the curb, rather than a placement in front of the curb. Combined, these results showed a strong perceptual-motor coupling in the task of approaching and stepping up a curb, rendering this task a suitable test for perceptual-motor regulation in walking

Associations between gait-related falls and gait adaptations when stepping onto a curb: A prospective falls study

Objectives. Examine gait regulation during the approach to stepping onto a curb for older adults who did or did not report gait-related falls over a 12-month follow-up. Methods. Ninety-eight participants aged 60 years and older were analyzed. Primary outcomes were step length adaptations (lengthening or shortening) during a curb approach and the occurrence of a gait-related fall during a 12-month follow-up. Results. Linear-mixed effects modelling indicated stronger adaptations towards the end of the approach. Participants who reported experiencing a gait-related fall showed a stronger relationship between the adjustment required and adjustment produced; indicating different gait adaptations during the step leading onto the curb. Discussion. The link between prospective gait-related falls and gait-adaptations indicated that older adults with reduced capabilities require stronger adaptations to complete tasks reminiscent of everyday life. This finding may provide insight into the mechanisms of falls in older adults and should inform new falls prevention interventions

On the ecological approach to Information and control for roboticists

The ongoing and increasingly important trend in robotics to conceive designs that decentralize control is paralleled by currently active research paradigms in the study of perception and action. James Gibson’s ecological approach is one of these paradigms. Gibson’s approach emerged in part as a reaction to representationalist and computationalist approaches, which devote the bulk of their resources to the study of internal processes. The ecological approach instead focuses on constraints and ambient energy patterns in the animal‐environment coalition. The present article reviews how the emphasis on the environment by ecological psychologists has given rise to the concepts of direct perception, higher order information, active information pick up, informationbased control laws, prospective control, and direct learning. Examples are included to illustrate these concepts and to show how they can be applied to the construction of robots. Action is described as emergent and self‐organized. It is argued that knowledge about perception, action, and learning as it occurs in living organisms may facilitate the construction of robots, more obviously so if the aim is to construct (to some extent) biologically plausible robots.This material is based upon work supported by grant FFI2009‐13416‐C02‐02 of the Spanish Ministry of Science and Innovation

Evaluating weaknesses of "perceptual-cognitive training" and "brain training" methods in sport: An ecological dynamics critique

The recent upsurge in "brain training and perceptual-cognitive training," proposing to improve isolated processes, such as brain function, visual perception, and decision-making, has created significant interest in elite sports practitioners, seeking to create an "edge" for athletes. The claims of these related "performance-enhancing industries" can be considered together as part of a process training approach proposing enhanced cognitive and perceptual skills and brain capacity to support performance in everyday life activities, including sport. For example, the "process training industry" promotes the idea that playing games not only makes you a better player but also makes you smarter, more alert, and a faster learner. In this position paper, we critically evaluate the effectiveness of both types of process training programmes in generalizing transfer to sport performance. These issues are addressed in three stages. First, we evaluate empirical evidence in support of perceptual-cognitive process training and its application to enhancing sport performance. Second, we critically review putative modularized mechanisms underpinning this kind of training, addressing limitations and subsequent problems. Specifically, we consider merits of this highly specific form of training, which focuses on training of isolated processes such as cognitive processes (attention, memory, thinking) and visual perception processes, separately from performance behaviors and actions. We conclude that these approaches may, at best, provide some "general transfer" of underlying processes to specific sport environments, but lack "specificity of transfer" to contextualize actual performance behaviors. A major weakness of process training methods is their focus on enhancing the performance in body "modules" (e.g., eye, brain, memory, anticipatory sub-systems). What is lacking is evidence on how these isolated components are modified and subsequently interact with other process "modules," which are considered to underlie sport performance. Finally, we propose how an ecological dynamics approach, aligned with an embodied framework of cognition undermines the rationale that modularized processes can enhance performance in competitive sport. An ecological dynamics perspective proposes that the body is a complex adaptive system, interacting with performance environments in a functionally integrated manner, emphasizing that the inter-relation between motor processes, cognitive and perceptual functions, and the constraints of a sport task is best understood at the performer-environment scale of analysis

Are age-related changes in perceptual-motor regulation related to an increased falls risk?

Introduction Decades of research have shown that approximately one in three older adults, aged 65 years or older, falls at least once each year (Campbell et al., 1990; World Health Organization, 2007). This is a problem in our ageing society; as the number of people in this aged cohort continues to increase, leading to an expected increase of falls and falls related medical costs in the coming years (Hendrie, Hall, Arena, & Legge, 2004). The consequences of falling are not only severe in terms of medical costs, for older adults a fall means injuries, decreases in quality of life and could even lead to death (Burns, Stevens, & Lee, 2016). The current thesis adopts an ecological approach to investigate opportunities for falls prevention. According to an ecological approach, guidance of action is mediated by the perception of ‘opportunities for action’ or ‘affordances’ (Gibson, 1979). These affordances are always action scaled; a person perceives possibilities for action in relation to his or her own action system. For instance, a curb might afford ‘stepping onto’ for me, as I have sufficient leg length and strength to perform a step up, however, it will afford ‘climbing onto’ for a toddler who’s legs might not yet have the length to afford stepping onto the curb. Perception of affordances is therefore influenced by how well a person knows his or her own capabilities or in other words how well one ‘calibrates’ perception and action. To achieve this calibration, one needs to experience of ‘explore’ one’s action system, or, as Gibson (1979) put it: "…we must perceive in order to move, but we must also move in order to perceive" (p. 213). This cyclic nature of perception forms the basis for the perception and action cycle and perceptual-motor coupling. The perception and action cycle can help to understand successful movement and therefore potentially to explain movement errors (such as the ones leading to falls) as well. If one component of the perception and action cycle is unsuccessful it could affect success in movement. For instance, if a person would not calibrate properly, making one insecure about one’s own action capabilities, it might lead to insecurities in moving around. From this it follows that for successful performance, it is important to successfully couple perception and action. Aims, Methods and Results per Study The current study incorporates four inter-related studies with differing methods. The first study (described in Chapter 2) is a systematic review, which sought to investigate the perceptual-motor calibration component of the perception and action cycle. The aim of this study was to assess in what conditions calibration occurs most efficiently, with a sub-aim to assess what is known about age-related changes in calibration. Seven databases were screened to identify literature that combined topics related to ‘perception’, ‘action’ and ‘calibration’ or ‘scaling’. Twenty-three papers satisfied the inclusion criteria. Results of the first study showed that calibration occurs rapidly if the movements performed to explore the perceptual and action coupling provide relevant information for perception. For instance, when standing height is raised by placing a participant on 10-cm high blocks, calibration occurred rapidly when participants were allowed to walk with the block (allowing much exploration), but not when only allowed standing stationary with no body movement (Mark, Balliett, Craver, Douglas, & Fox, 1990). Furthermore, this study identified a general limitation in the research on calibration; no studies have been identified that have studied calibration to changed action capabilities in an older cohort. The second, third and fourth study in this thesis (described in Chapter 4, Chapter 5 and Chapter 6) all use the same ‘curb-approach task’ to study the regulation of gait towards a target. For each trial in the curb approach task, participants were positioned at the far end of an 8m long GAITRite pressure sensitive walkway (GAITRite®, CIR Systems, Inc., Franklyn, NJ, USA). At a ‘go’ signal, participants started walking the length of the walkway (placing one footfall on a target that was randomly placed in the first 3 meters of the walk to prevent participants from performing identical walks in each trial), to the end of the walkway where a curb-like platform (L: 2m, W: 1m, H: 0.15m) was positioned. Participants stepped onto the platform and continued to the far end at which a push-button was positioned that signaled the end of the trial. 33 trials were performed per participant. Outcome measures of the curb-approach task were related to three analyses introduced in previous studies in locomotor pointing (De Rugy, Taga, et al., 2002; Montagne et al., 2000). Firstly, an analysis was introduced that assessed the changes in variability (standard deviation) of the position of foot placements. Secondly, an analysis was introduced that assessed whether the timing of the initiation of adaptations in gait (deviations from a ‘standard’ step) are related to the total amount of adjustments to be made (indicating a perception-action coupling). Finally, an analysis was introduced VII that assessed the strength of perceptual-motor coupling; the degree to which changes in step length depended on the perception of required adjustments. The second study (as described in Chapter 4) aimed to assess whether successful performance in the curb-approach task required similar perceptual-motor regulation compared to the long-jump run up. Sixteen younger adults were included and ask to perform the curb-approach task. Results confirmed the similarities between the curb-approach and the long jump approach. Regulation seemed to be initiated earlier in the curb-approach compared to the long jump, but a similar pattern was observed in decreasing variability of foot placement and an increasingly stronger perceptual-motor coupling as participants got closer to their target in both tasks. The second study concluded that the curb-approach task would provide an effective paradigm to study perceptual-motor regulation in an older cohort (for whom a long jump would be too demanding). The third study (Chapter 5) aimed to assess age-related changes in regulation in the curb approach task. In this study, the data collected from the 16 younger participants (study2) was compared to data collected from a cohort of 105 older adults. Results showed that with older age, participants showed less variability in foot placement during their approach. Furthermore, it was shown that with age, participants were more likely to adopt a strategy that involved shortening rather than lengthening of steps. Age-related changes were most prominent in the measures of strength of perceptual-motor regulation. Similar to the younger participants, older participants showed an increased strength of coupling (or in other words; made stronger adjustments) as they got closer to the curb. However, it was also shown that with age the strength of the coupling over all steps increased, indicating that the older participants made stronger gait adaptations. As the third study identified that age-related changes are most prominent in the measures of perceptual-motor coupling, it was decided to focus the final study (Chapter 6) on the question whether these changes could be related to an increased risk of falls. Ninety-eight participants were included in the analysis for this study, who first performed the curb-approach task and then were entered in a 12 –month follow-up to screen for the occurrence of gait-related falls. Results showed that participants who reported experiencing a gait-related fall showed stronger perceptual-motor coupling (stronger gait adaptations) in stepping onto the curb. Discussion and Conclusion The results of this thesis showed that the curb-approach task provides a novel and valid method to measure perceptual-motor regulation of locomotor pointing in in a low demands setting, suitable for the older cohort. Older adults showed stronger gait adaptations compared to their younger counterparts and adaptations in the step onto the curb were stronger still in on older adults prone to experiencing gait-related falls. These results suggest that, in controlling gait, humans are capable of changing the strength of perceptual-motor coupling in accordance with the difficulty of the task. With age, action capabilities decrease and the curb-approach task becomes harder; our results show that this is met with a strengthening of perceptual-motor coupling. Implications of the current thesis are that in falls risk screenings as well as falls prevention, it is important to consider the entire perception and action cycle. An ecologically-grounded functional approach to healthy aging is advocated which considers a person in relation to his/her behavior and environment (Vaz, Silva, Mancini, Carello, & Kinsella-Shaw, 2017)

Multisensory integration in complex rhythmic motor tasks

This publication-based thesis aimed to shed further light on the contributions of visual and auditory information to the execution of complex rhythmic motor tasks. To this end, a series of three empirical studies was designed. The first two studies were conducted in the experimental setting of long jumping – a task that does not only require high precision but also high velocity to leap as far as possible. Within the first study, we aimed to examine visual regulation during the long jump run-up using portable eye-tracking technology. Previous research on the topic of visual regulation in long jumping has identified a universal instance in participants’ gait behavior which introduces a rapid decrease in step variability. Since then, this parameter was considered synonymous with the (gait-based) onset of visual regulation. However, an investigation of actual visual behavior by means of direct measures was still pending to date. Hence, the first study was designed to identify a potential equivalent to the gait-based parameter within participants’ gaze behavior. Results revealed that the moment of the longest gaze on the take-off board coincided with the occurrence of the well-established gait parameter. Given that i) the gait-based visual regulation parameter has been associated with a reduction in footfall variability and ii) current research advocates the idea that fixations of longer duration facilitate motor actions, one might speculate that the longest gaze on the take-off board might as well serve the reduction of movement variability. While the parameter of visual regulation could be characterized in more detail within the first empirical investigation, the impact of other modalities has been neglected so far. However, current research is promoting the idea that, apart from visual information, auditory information might as well be crucial for the execution of motor tasks. ..

Perception-action coupling model for human locomotor pointing

How do humans achieve the precise positioning of the feet during walking, for example, to reach the first step of a stairway? We addressed this question at the visuomotor integration level. Based on the optical specification of the required adaptation, a dynamical system model of the visuomotor control of human locomotor pointing was devised for the positioning of a foot on a visible target on the floor during walking. Visuomotor integration consists of directly linking optical information to a motor command that specifically modulates step length in accordance with the ongoing dynamics of locomotor pattern generation. The adaptation of locomotion emerges from a perception-action coupling type of control based on temporal information rather than on feedforward planning of movements. The proposed model reproduces experimental results obtained for human locomotor pointing

Constraints on movement variability during a discrete multi-articular action

The aim of this programme of work was to examine how the manipulation of organismic and task constraints affected movement variability during a basketball shooting task. The specific constraints that were manipulated included task expertise, state anxiety and dioptric blur (organismic constraints), and, shooting distance and attentional focus instruction (task constraints). The aim of Study 1 was to investigate the effect of shooting distance and task expertise on movement variability. Task expertise was characterised by decreased coordination variability and heightened compensatory variability between wrist, elbow and shoulder joints. However, no significant difference was found in joint angle variability at release as a function of task expertise. There was no significant change in movement variability with shooting distance, a finding that was consistent across all expertise groups. In Study 2, the aims were to examine the effect of induced dioptric blur on shooting performance and movement variability during basketball free-throw shooting, and, to ascertain whether task expertise plays a mediating role in the capacity to stabilise performance against impaired visual information. Significant improvements in shooting performance were noted with the introduction of moderate visual blur (+1.00 and +2.00 D). This performance change was evident in both expert and novice performers. Only with the onset of substantial dioptric blur (+3.00 D), equivalent to the legal blindness limit, was there a significant decrease in coordination variability. Despite the change in coordination variability at +3.00 D, there was no significant difference in shooting performance when compared to the baseline condition. The aims of Study 3 were to examine the effect of elevated anxiety on shooting performance and movement variability and, again, to determine whether task expertise plays a mediating role in stabilising performance and movement kinematics against perturbation from emotional fluctuations. Commensurate with the results of Study 2, both expert and novice performers were able to stabilise performance and movement kinematics, this time with elevated anxiety. Stabilisation was achieved through the allocation of additional attentional resources to the task. Study 4, had two aims. The first was to examine the interactive effects of practice and focus of attention on both performance and learning of an accuracy-based, discrete multi-articular action. The second was to identify potential focus-dependent changes on joint kinematics, intra-limb coordination and coordination variability. Support was found for the role of an external focus of attention on shooting performance during both acquisition and retention. However, there was evidence to suggest that internal focus instruction could play a pivotal role in shaping emerging patterns of intra-limb coordination and channelling the learners‟ search towards a smaller range of kinematic solutions within the perceptual-motor workspace. Collectively, this programme of work consistently highlighted the fundamental role that constraints play in governing shooting performance, movement variability and, more broadly, perceptual-motor organisation. For instance, task expertise was characterised by decreased coordination variability and heightened compensatory control. However, in light of the data pertaining to joint angle variability at release, general assumptions about expertise-variability relations cannot be made and should be viewed with caution. In addition, there is strong evidence to suggest that adaptation to constraints is, perhaps, a universal human response, and consequently not mediated by task expertise. Further research is needed to fully elucidate this proposition

Οπτική αντίληψη και έλεγχος μετακίνησης σε δεξιότητες προσέγγισης στόχου, με εφαρμογή στα αγωνίσματα των εμποδίων και του άλματος σε μήκος – Προπονητική και Διδακτική προσέγγιση.

Σε δεξιότητες προσέγγισης στόχου, η εφαρμογή του οπτικού ελέγχου και η προσαρμογή του μήκους των διασκελισμών αποτελούν βασικές ανθρώπινες δεξιότητες. Κατά την εκτέλεση του άλματος σε μήκος, νεαροί, αρχάριοι αθλητές και αθλήτριες προσαρμόζουν το μήκος των τελευταίων διασκελισμών της φόρας τους σύμφωνα με το οπτικό ερέθισμα (βαλβίδα), υποστηρίζοντας την εφαρμογή του οπτικού ελέγχου. Η τεχνική του οπτικού ελέγχου δεν εφαρμόζεται μόνο σε συγκεκριμένες μορφές δεξιότητας όπου απαιτείται η τοποθέτηση του πέλματος σε ένα συγκεκριμένο στόχο στο έδαφος, αντίθετα, πρόκειται για την ύπαρξη ενός γενικού μηχανισμού ελέγχου ο οποίος βασίζεται στο συνδυασμό αντίληψης – κίνησης. Ο μηχανισμός αυτός οπτικού ελέγχου εφαρμόζεται και κατά την προσέγγιση αγωνιστικών εμποδίων, μια κινητική δεξιότητα η οποία χαρακτηρίζεται από διαφορετικές απαιτήσεις κίνησης και εκτελείται σε ένα περιβάλλον με διαφορετικά ερεθίσματα πληροφόρησης. Ωστόσο, το περιβάλλον απόδοσης και οι περιορισμοί της δεξιότητας επηρεάζουν το μοντέλο των διασκελισμών κατά τη φάση της φόρας και την εφαρμογή του οπτικού ελέγχου. Καθώς οι ενέργειες προσέγγισης στόχου έχουν μια εξελίξιμη πορεία, η ικανότητα ρύθμισης του μοντέλου μετακίνησης μπορεί να βελτιωθεί μέσω της μάθησης – εξάσκησης. Ένα μαθησιακό – προπονητικό περιεχόμενο βασισμένο στην προσέγγιση του μοντέλου των περιορισμών, το οποίο προσφέρει όλες τις δυνατότητες για να αναπτυχθούν τα σημαντικά χαρακτηριστικά της δεξιότητας, μπορεί να συμβάλλει σε μια βελτιωμένη κινητική συμπεριφορά, από άποψη όχι μόνο μιας βελτιωμένης ικανότητας ρύθμισης του μοντέλου διασκελισμών κατά τη φάση προσέγγισης του στόχου αλλά και σε σχέση με τα χαρακτηριστικά τεχνικής της κινητικής δεξιότητας.In target directed locomotion, the occurrence of visual control and step adjustment are basic human skills. Assessing the long jump approach run, young, novice long jumpers adjust the final steps of their approach according to the regulatory stimuli (takeoff board), suggesting the use of a continuous visual control process. This control mechanism involved is based on a continuous perception – movement coupling and is implemented regardless of the specificity of tasks (pointing a target or stepping across an obstacle). Even though track and field hurdling is characterized by different task constraints, young athletes also adjust their step pattern in order to effectively clear the hurdle, suggesting a visual regulation similar to that reported for long jumpers. However, step pattern and technical aspects of the approach run are affected by environmental context and nested task constraints. The regulation of the locomotion pattern according to visual input seems to be an emergent behavior, which could be improved through practice. A learning design based on the constraints-led approach, which contains all the necessary informational elements of the performance environment and provide opportunities to develop the key elements of the skill, could contribute to an improved motor skill in terms not only of an improved ability to regulate step pattern but of technical characteristics as well

Coaching for the game of life: Driving coaching with mana

Coaching needs to account for culture. This indigenous autoethnography explores personal experience to show how I, a young Māori male coach in Aotearoa New Zealand, navigates the complex nature of coaching. By weaving together Kaupapa Māori, established coaching knowledge, and experiences from my playing and coaching journey to date, a Kaupapa Māori coaching framework emerges – Driving Coaching with Mana. As I reflect on the teachings of my coach, Mr. Mel Young, combined with my cultural identity, I reconnect to critical moments in my life that have shaped the person I am today and the values I hold, elevating the centrality of culture through the practice of Kaupapa, Ako, Manaakitanga, Whanaungatanga, Wairuatanga, and self-reflection as Āta-kaiako (a reflective coach). Driven to enhance the development of rangatahi (youth) through sport, and informed by literature and experience, Driving Coaching with Mana is personally and culturally grounded – a way of thinking about coaching differently and in a more holistic way. There is more to the people we coach than their lives as athletes. Coaching is more than skill acquisition