Effects of Developmental Task Constraints on Kinematic Synergies during Catching in Children with Developmental Delays

Abstract

The aim of this study was to examine effects of a task intervention on kinematic synergies in catching. Participants were young children (5.58?±?0.52?years) with the lowest scores on two-hand catching, according to assessments with the Test of Gross Motor Development-2 (TGMD-2) and were allocated into two groups. The constraints group took part in an 8-week intervention, whereas the control group experienced a typical physical education. Both groups were assessed with motor development and kinematic coordination measures with a catching task with a ball thrown from 2?m distance. Kinematic variables were recorded using a wireless motion capture system. A principal component analysis (PCA) was used to measure the kinematic synergies formed among active body parts. Two synergies that emerged in catching were mainly utilised for “reaching” and “catching” the ball. The control group tended to re-organise the majority of active body parts into two functional units in all phases, whereas the constraints group adapted their active parts into functional units according to the requirement of the novel movement in the transfer task. The findings of this study suggested that task constraints could facilitate object control by re-organisation of active body parts into functional synergies to achieve successful performance.     

From anger to solidarity: The emotional echo-chamber of Gezi park protests

By using the Gezi Park protests that took place in Turkey in 2013 as a case, we explore the significance of emotional echo-chamber involved in protests. The analyses are composed of thirty-seven interviews conducted with activists on how they define and understand their preferences and motivations for protesting. We discuss how participants get influenced by beliefs, motives and opinions and bring forth the changes of emotions during such processes and help create an emotional echo-chamber.     

When Racism Gets Personal: Toward Relational Healing

SUMMARY

In a culture that stratifies human differences, it is inevitable that anxiety about difference would be the source of much suffering. The power distortions that lie at the root of this suffering are manifest in relationships, from the most tangential to those that are deeply intimate. Moreover, the anxieties endemic to a race-based culture have the potential to thwart our most earnest efforts to make and maintain good connection. To adopt the feminist perspective, that the personal is political, is to acknowledge that no relationship can remain unscathed when power and value are differentially accorded based on racial group membership.

Three examples from clinical practice will be used to illustrate how racial anxiety impedes movement toward authenticity, mutuality, and empowerment in intimate relationships. In these examples, three biracial women who identify as black navigate the racial stratifications that contaminate the inevitable conflicts in their relationships with parents, mentors, and lovers. Because of the multilayered anxieties stemming from living and loving in a racially stratified culture, conflicts, which might otherwise be the source of growth and deeper connection, become rigidified and immobilizing. In addition to examining the debilitating impact of racial anxiety, the presentation will highlight the relational processes that facilitate healing, resilience, and mutual empowerment.     

单字词和复合词预视加工的差异性研究：词边界信息无影响

本实验采用眼动轨迹记录法并结合边界范式（Rayner, 1975），操纵单字词和双字复合词的首字为一致预视或假字预视，考察单字词和复合词预视加工的差异性。另外，通过在中文句子中加入词边界信息——词间阴影，以考察词间阴影对单字词和复合词预视加工的影响。实验结果表明，复合词的预视效应大于单字词，并且词间阴影对单字词和复合词的预视加工均没有显著影响。因此，与印欧语系相比，中文阅读中更大更强的预视效应需从更深层次的语言和认知因素进行探讨。该结果更倾向于支持词切分和词汇识别模型。     

Synthesis of asymmetric movement trajectories in timed rhythmic behaviour by means of frequency modulation

Results from different empirical investigations on gestural aspects of timed rhythmic movements indicate that the production of asymmetric movement trajectories is a feature that seems to be a common characteristic of various performances of repetitive rhythmic patterns. The behavioural or neural origin of these asymmetrical trajectories is, however, not identified. In the present study we outline a theoretical model that is capable of producing syntheses of asymmetric movement trajectories documented in empirical investigations by Balasubramaniam et al. (2004). Characteristic qualities of the extension/flexion profiles in the observed asymmetric trajectories are reproduced, and we conduct an experiment similar to Balasubramaniam et al. (2004) to show that the empirically documented movement trajectories and our modelled approximations share the same spectral components. The model is based on an application of frequency modulated movements, and a theoretical interpretation offered by the model is to view paced rhythmic movements as a result of an unpaced movement being “stretched” and “compressed”, caused by the presence of a metronome. We discuss our model construction within the framework of event-based and emergent timing, and argue that a change between these timing modes might be reflected by the strength of the modulation in our model.     

A systematic review on perceptual-motor calibration to changes in action capabilities

Perceptual-motor calibration has been described as a mapping between perception and action, which is relevant to distinguish possible from impossible opportunities for action. To avoid movement errors, it is relevant to rapidly calibrate to immediate changes in capabilities and therefore this study sought to explain in what conditions calibration is most efficient. A systematic search of seven databases was conducted to identify literature concerning changes in calibration in response to changes in action capabilities. Twenty-three papers satisfied the inclusion criteria. Data revealed that calibration occurs rapidly if there is a good match between the task that requires calibration and the sources of perceptual-motor information available for exploration (e.g. when exploring maximal braking capabilities by experiencing braking). Calibration can take more time when the perceptual-motor information that is available is less relevant. The current study identified a number of limitations in the field of perceptual-motor research. Most notably, the mean participant age in the included studies was between 18 and 33 years of age, limiting the generalizability of the results to other age groups. Also, due to inconsistent terminology used in the field of perceptual-motor research, we argue that investigating calibration in older cohorts should be a focus of future research because of the possible implications of impaired calibration in an aging society.     

A Riemannian geometry theory of human movement: The geodesic synergy hypothesis

Mass-inertia loads on muscles change with posture and with changing mechanical interactions between the body and the environment. The nervous system must anticipate changing mass-inertia loads, especially during fast multi-joint coordinated movements. Riemannian geometry provides a mathematical framework for movement planning that takes these inertial interactions into account. To demonstrate this we introduce the controlled (vs. biomechanical) degrees of freedom of the body as the coordinate system for a configuration space with movements represented as trajectories. This space is not Euclidean. It is endowed at each point with a metric equal to the mass-inertia matrix of the body in that configuration. This warps the space to become Riemannian with curvature at each point determined by the differentials of the mass-inertia at that point. This curvature takes nonlinear mass-inertia interactions into account with lengths, velocities, accelerations and directions of movement trajectories all differing from those in Euclidean space. For newcomers to Riemannian geometry we develop the intuitive groundwork for a Riemannian field theory of human movement encompassing the entire body moving in gravity and in mechanical interaction with the environment. In particular we present a geodesic synergy hypothesis concerning planning of multi-joint coordinated movements to achieve goals with minimal muscular effort.     

How Change Happens: Controlling Images,Mutuality, and Power

SUMMARY

Change is inevitable but it can go in a positive direction toward growth or in a negative direction. Extending Patricia Hill Collins' concept of controlling images (2000), we can see how these images interact with relational images and strategies of disconnection to obstruct growth on both the societal and the personal level. In therapy, change is defined as movement-in-relationship toward better connection; and increased connection leads to growth. Several aspects of therapy that lead to deeper and wider connection are explored, especially increasing the patient's power. Prior versions of parts of this article were presented at the Jean Baker Miller Summer Training Institutes in 2001 and 2002 and at the 2002 Learning from Women Conference sponsored by the Jean Baker Miller Training Institute and the Harvard Medical School/Cambridge Hospital in Boston, Massachusetts.

As therapists, we're “in the business” of change–change for the better. That's our goal. Another word for change for the better is growth. Change is the essence of life. It is most obvious in children but it is a necessity through all of life. Change will occur inevitably but it can go in a positive or a negative direction. Further, I believe change toward growth creates pleasure. We feel most alive and zestful when we are engaged in this expanding activity.     

Sense of agency disturbances in movement disorders: A comprehensive review

Sense of agency refers to the experience that one’s self-generated action causes an event in the external environment. Here, we review the behavioural and brain evidence of aberrant experiences of agency in movement disorders, clinical conditions characterized by either a paucity or an excess of movements unrelated to the patient’s intention. We show that specific abnormal agency experiences characterize several movement disorders. Those manifestations are typically associated with structural and functional brain abnormalities. However, the evidence is sometimes conflicting, especially when considering results obtained through different agency measures. The present review aims to create order in the existing literature on sense of agency investigations in movement disorders and to provide a coherent overview framed within current neurocognitive models of motor awareness.     

Omniscient gods and precision and intent in rituals: the case of Orthodox Judaism

ABSTRACT

Social scientists who study the minds of gods claim that the omniscient gods of monotheistic religions are aware of the intent of their followers, unlike gods who are not omniscient. For this reason, omniscient gods do not place emphasis on their followers’ precision in carrying out rituals, focusing rather on the intent and/or identity of the practitioners. The present article challenges this perception by focusing on several spheres of Orthodox Judaism in Israel. In each of these spheres, less attention is paid to the actual intent and identity of those practising the ritual, with far more attention directed to not only the actual execution of the ritual, but also the precision with which it is executed. Moreover, when rituals of healing are involved, imprecise or incomplete execution of such rituals can be used to explain their failure.