Form and Variability During Sit-to-Stand Transitions: Children Versus Adults

In performing the sit-to-stand transition, young children (6- to 7-year-olds) were expected to display a movement form similar to that of adults. However, movement consistency was predicted to be poorer in children than in adults because they lack refinement of motor control processes. Kinematic analysis of 10 repetitions of the sit-to-stand movement was carried out for 6 typically developing children and 6 adults. Supporting the authors' prediction of comparable form, no differences were evident between age groups for sequence of joint onsets, proportional duration of segmental motion, or in angle-angle plots of displacement at 2 segments. In contrast, within-participant variability was found to be higher for children: Coefficients of variation for most kinematic measures were twice those seen for adults. The authors interpret the children's lack of movement consistency as a reflection of inadequate stabilization of an internal model of intersegmental dynamics. Whereas adults have attained a skill level associated with refinement of that model, children have not. Children have an additional control problem because changes in body morphology throughout childhood require ongoing updating of the internal model that controls intrinsic dynamics.     

EMG Activity as a Function of the Performer's Focus of Attention

In previous studies of attentional focus effects, investigators have measured performance outcome. Here, however, the authors used electromyography (EMG) to determine whether differences between external and internal foci would also be manifested at the neuromuscular level. In 2 experiments, participants (N = 11, Experiment 1; N = 12, Experiment 2) performed biceps curls while focusing on the movements of the curl bar (external focus) or on their arms (internal focus). In Experiment 1, movements were performed faster under external than under internal focus conditions. Also, integrated EMG (iEMG) activity was reduced when performers adopted an external focus. In Experiment 2, movement time was controlled through the use of a metronome, and iEMG activity was again reduced under external focus conditions. Those findings are in line with the constrained action hypothesis (G. Wulf, N. McNevin, & C. H. Shea, 2001), according to which an external focus promotes the use of more automatic control processes.     

Timing Precision in Circle Drawing Does Not Depend on Spatial Precision of the Timing Target

The authors manipulated the width of a timing target in continuous circle drawing to determine whether a more stringent spatial-timing criterion would produce an increase in participants' (N = 30) temporal variability. They also examined the effect of the computational method of determining cycle duration. There was no effect of spatial precision on temporal variability in circle drawing, and tapping and circle drawing were found to use the same criterion. Those findings lend strong support to the earlier view of R. B. Ivry, R. M. Spencer, H. N. Zelaznik, and J. Diedrichsen (2002), who argued that continuous tasks such as circle drawing are timed differently from discrete-like tasks such as tapping. Therefore, the results of the present study provide support for the event and emergent timing frameworks.     

Effect of Concurrent Visual Feedback Frequency on Postural Control Learning in Adolescents

The purpose was to find better augmented visual feedback frequency (100% or 67%) for learning a balance task in adolescents. Thirty subjects were divided randomly into a control group, and 100% and 67% feedback groups. The three groups performed pretest (3 trials), practice (12 trials), posttest (3 trials) and retention (3 trials, 24 hours later). The reduced feedback group showed lower RMS in the posttest than in the pretest (p = 0.04). The control and reduced feedback groups showed significant lower median frequency in the posttest than in the pretest (p < 0.05). Both feedback groups showed lower values in retention than in the pretest (p < 0.05). Even when the effect of feedback frequency could not be detected in motor learning, 67% of the feedback was recommended for motor adaptation.     

《周易》阴阳论的层级结构性质

传统中国哲学中的阴阳论一直是学界所关注的一个焦点,但对于该体系所具备确切内涵的各方面、以及由其所结成的整个架构的整体理论性质,却很少有人能深入体察。本文通过对《周易》阴阳论的细致分析,提出该理论作为一种形而上学宇宙论,实则是一个内在含括生命论、差异论与秩序论等三个主要方面,并以其中生命论为根基也是最终目的的层级结构。     

Psychometric Properties of the Family Support Scale with Head Start Families

Social support systems can have either a beneficial or adverse effect when a family faces stress. Hence, support perceived by family members is an important construct. We studied the psychometric properties of the Family Support Scale (FSS) with a sample of 244 low-income families of children in a Head Start program, and we conducted an exploratory factor analysis with the scale. We obtained a 5-factor solution for the FSS when assessing the family support of low-income families. The internal consistency and test-retest reliability were moderately high for the 5 proposed subscales. The factor structure obtained may prove more valid for Head Start families than structures from previous studies, although there is still a need for further psychometric study of the FSS.     

Acquiring a Novel Coordination Skill without Practicing the Correct Motor Commands

There is evidence that experience of the sensory consequences, in the absence of practice of the required motor commands, is sufficient to learn new bimanual coordination patterns. This was shown through improvements of an incongruent group who practiced a desired 30° phase offset between the limbs while 1 limb was weighted such that the desired phase relation was achieved when synchronous motor commands were sent to the limbs (P. Atchy-Delama, P. G. Zanone, C. E. Peper, & P. J. Beek, 2005). In addition to testing a similar incongruent and congruent group (i.e., no weight), the authors extended this experiment by removing visual feedback during practice and by including an auditory modeling and passive guidance group. All groups showed improvement, except for the modeling group. The passive guidance group made more errors in posttests than the congruent and incongruent groups. Only the congruent group increased the amount of time around 30° after practice. Active experience of the sensory consequences combined with practice sending appropriate motor commands is the most effective method for learning, even though strategic improvements can be attained without experience of the latter.     

Adaptation to a Nonlinear Visuomotor Amplitude Transformation With Continuous and Terminal Visual Feedback

The control of a cursor on a computer monitor offers a simple means of exploring the limits of the plasticity of human visuomotor coordination. The authors explored the boundary conditions for adaptation to nonlinear visuomotor amplitude transformations. The authors hypothesized that only with terminal visual feedback during practice, but not with continuous visual feedback, humans might develop an internal model of the nonlinear visuomotor amplitude transformation. Thus, 2 groups were engaged in a sensorimotor adaptation task receiving either continuous or terminal visual feedback during the practice phase. In contrast to expectations, adaptive shifts and aftereffects observed in visual open-loop tests were linearly related to target amplitudes for both groups. Although the 2 feedback groups did not differ with respect to adaptive shifts and aftereffects, terminal visual feedback resulted in stable visual open-loop performance for an extended period, whereas movement errors increased after continuous visual feedback during practice. The benefit of continuous visual feedback, on the other hand, was faster closed-loop performance, indicating an optimization of visual closed-loop control.     

A Child Trauma Treatment Pilot Study

We examined outcomes of a promising 21-session trauma treatment model for children aged 3 to 17 and their caregivers. All children in treatment had experienced at least one traumatic event. The treatment intervention was rooted in theories of trauma and attachment and combines parent training with cognitive behavioral therapy to form a comprehensive trauma treatment program. We report on 27 families who completed the program. Results reflect significant reductions in conduct disorder, problems in social relations, and caregiver depression at an average of a one-year post-treatment follow-up. Results from our preliminary study offer support for further evaluation of the model.     

Physical characteristics of residential psychiatric and substance abuse programs: Organizational determinants and patient outcomes

Described the Physical and Architectural Characteristics Inventory (PACI), which assesses the physical characteristics of hospital- and community-based psychiatric and substance abuse residential treatment programs for adults. Developed using data from 94 representative programs, the PACI has 7 dimensions that assess community accessibility, physical features that add convenience, aid recreation, and provide support for patients, and space for patient and staff functions. In comparison to community-based programs (n=63), hospital programs (n=31) had more social-recreational and prosthetic aids, safety features, staff facilities, and space. The PACI dimensions were also related to other organizational features, such as facility ownership and program size and staffing level. Programs with more physical amenities had patients who were more involved in self-initiated and community activities and were more likely to successfully complete the program and be discharged to independent living situations and paid jobs. Programs with more social-recreational and prosthetic aids, space, and access to community resources also had better patient outcomes. In addition, PACI dimensions were related to observers' ratings of facility attractiveness. Potential applications of the PACI and the full inventory of which it is a part are discussed.