The impact of speed and time on gait dynamics

To determine the effects of speed on gait previous studies have examined young adults walking at different speeds; however, the small number of strides may have influenced the results. The aim of this study was to investigate the immediate and long-term impact of continuous slow walking on the mean, variability and structure of stride-to-stride measures. Fourteen young adults walked at a constant pace on a treadmill at three speeds (preferred walking speed (PWS), 90% and 80% PWS) for 30 min each. Spatiotemporal gait parameters were computed over six successive 5-min intervals. Walking slower significantly decreased stride length, while stride period and width increased. Additionally, stride period and width variability increased. Signal regularity of stride width increased and decreased in stride period. Persistence of stride period and width increased significantly at slower speeds. While several measures changed during 30 min of walking, only stride period variability and signal regularity revealed a significant speed and time interaction. Healthy young adults walking at slower than preferred speeds demonstrated greater persistence and signal regularity of stride period while spatiotemporal changes such as increased stride width and period variability arose. These results suggest that different control processes are involved in adapting to the slower speeds.     

Local dynamic stability of the spine and its coordinated lower joints during repetitive Lifting: Effects of fatigue and chronic low back pain

The nonlinear Lyapunov exponent (LyE) has been proven effective for evaluating the local stability of human movement and exploring the effects of load, speed and direction of individuals with and without nonspecific chronic low back pain (CLBP). The purpose of this study was to examine spinal and lower joint stability and response to fatigue of individuals with and without CLBP while performing lifting-lowering movements. Fourteen healthy individuals and 14 patients with nonspecific CLBP were recruited to perform lifting movement repeatedly while holding two equally-sized dumbbells in their hands. The participants continued lifting until they reported their highest level of fatigue. Kinematic data for the spine and its coordinated lower joints were recorded during the task (more than 40 lifting cycles on average). The first and last 20 cycles of each cyclic time series were defined as early- and late-fatigue conditions, respectively. The maximum LyE was estimated to quantify the local dynamic stability of the angular displacement time series of the spine, hip, knee and ankle on different anatomical planes in both the early- and late-fatigue conditions. The results revealed that local stability of the spine and hip was affected by fatigue. Spinal stability decreased as fatigue increased on the sagittal plane (p < 0.05). The hip exhibited a similar affectation (destabilization under fatigue) on all anatomical planes. Patients with CLBP showed more stable hip movement on the frontal and transverse planes (p < 0.05). These results suggested that lifting/progressive fatigue could increase the risk of injury to the spine and hip. These findings indicate that patients with CLBP applied different control strategies for the hip; thus, spinal control stability should be evaluated together with the stability of the lower joints.     

The influence of a long term exercise program on lower limb movement variability and walking performance in patients with peripheral arterial disease

The purpose of this study was to examine the effects of a 12 month exercise program on lower limb movement variability in patients with peripheral arterial disease (PAD). Participants (n = 21) with an appropriate history of PAD and intermittent claudication (IC) volunteered for this study and were randomly allocated to either a control group (CPAD–IC) (n = 11), which received normal medical therapy and a treatment group (TPAD–IC) (n = 10), which received normal medical therapy treatment and a 12 month supervised exercise program. All participants underwent 2D joint angular kinematic analysis during normal walking to assess lower limb movement variability and walking speed. Between-group differences were analyzed via mixed measures ANOVA. The 12 month supervised exercise program made no significant impact on the lower limb movement variability or walking speed of the TPAD–IC group as determined by either intralimb joint coordination or single joint analysis techniques. Long term supervised exercise programs do not appear to influence the lower limb movement variability of PAD–IC patients.     

Nonlinear approach to study the acute effects of static and dynamic stretching on local dynamic stability in lower extremity joint kinematics and muscular activity during pedalling

Researchers have reported contradictory results on the effect of static and dynamic stretching on subsequent performance. Due to the importance of performance through static and dynamic stretching, the aim of this study is to investigate the acute effects of static and dynamic stretching protocols on local dynamic stability in lower extremity joint kinematics and muscular activities during pedalling using a nonlinear dynamics approach. Using a randomised crossover trial design, fifteen active males participated voluntarily in this research (mass: 69.02 ± 10.52 kg, height: 174.00 ± 6.74 cm, and age: 21.20 ± 1.47 years) and completed a pedalling trial in situations of without stretching (WS), after static (SS), and dynamic stretching (DS) of lower extremity. The lower extremity joint angles in the sagittal plane and the electrical activity of soleus, gastrocnemius medialis, tibialis anterior, vastus medialis, biceps femoris, and rectus femoris muscles were collected during 30 pedalling cycles at 70 rates per minute. The results of the repeated measure ANOVA indicated that the knee and ankle angle largest LyE was significantly lower in DS compared to WS and SS. The largest LyE in muscle activity is also significantly lower for all the muscles after DS compared to WS and SS (P ≤ 0.05). Regarding the positive effects of DS on the joints and the muscle activity local dynamic stability, it is suggested to use DS than SS in the warm-up program before repetitive activities like pedalling.     

Level walking in adults with and without Developmental Coordination Disorder: An analysis of movement variability

Several studies have shown that Developmental Coordination Disorder (DCD) is a condition that continues beyond childhood. Although adults with DCD report difficulties with dynamic balance, as well as frequent tripping and bumping into objects, there have been no specific studies on walking in this population. Some previous work has focused on walking in children with DCD but variation in the tasks and measures used has led to inconsistent findings. The aim of the current study therefore was to examine the characteristics of level walking in adults with and without DCD. Fifteen adults with DCD and 15 typically developing (TD) controls walked barefoot at a natural pace up and down an 11 m walkway for one minute. Foot placement measures and velocity and acceleration of the body were recorded, as well as measures of movement variability. The adults with DCD showed similar gait patterns to the TD group in terms of step length, step width, double support time and stride time. The DCD group also showed similar velocity and acceleration to the TD group in the medio-lateral, anterior–posterior and vertical direction. However, the DCD group exhibited greater variability in all foot placement and some body movement measures. The finding that adults with DCD have a reduced ability to produce consistent movement patterns is discussed in relation to postural control limitations and compared to variability of walking measures found in elderly populations.     

The effects of sub-threshold vibratory noise on visuomotor entrainment during human walking and standing in a virtual reality environment

Humans will naturally synchronize their posture to the motion of a visual surround, but it is unclear if this visuomotor entrainment can be attenuated with an increased sensitivity to somatosensory information. Sub-threshold vibratory noise applied to the Achilles tendons has proven to enhance ankle proprioception through the phenomenon of stochastic resonance. Our purpose was to compare visuomotor entrainment during walking and standing, and to understand how this entrainment might be attenuated by applying sub-threshold vibratory noise over the Achilles tendons. We induced visuomotor entrainment during standing and treadmill walking for ten subjects (24.5 ± 2.9 years) using a speed-matched virtual hallway with continuous mediolateral perturbations at three different frequencies. Vibrotactile motors over the Achilles tendons provided noise (0–400 Hz) with an amplitude set to 90% of each participant’s sensory threshold. Mediolateral sacrum, C7, and head motion was greatly amplified (4–8× on average) at the perturbation frequencies during walking, but was much less pronounced during standing. During walking, individuals with greater mediolateral head motion at the fastest perturbation frequency saw the greatest attenuation of that motion with applied noise. Similarly, during standing, individuals who exhibited greater postural sway (as measured by the center of pressure) also saw the greatest reductions in sway with sub-threshold noise applied in three of our summary metrics. Our results suggest that, at least for healthy young adults, sub-threshold vibratory noise over the Achilles tendons can slightly improve postural control during disruptive mediolateral visual perturbations, but the applied noise does not substantially attenuate visuomotor entrainment during walking or standing.     

Effects of differences in interreinforcer intervals between past and current schedules on fixed-interval responding

Undergraduates were exposed to a mixed fixed-ratio differential-reinforcement-of-low-rate schedule. Values of the schedule components were adjusted so that interreinforcer intervals in one component were longer than those in another component. Following this, a mixed fixed-interval 5-s fixed-interval 20-s schedule (Experiment 1) or six fixed-interval schedules in which the values ranged from 5 to 40 s (Experiment 2) were in effect. In both experiments, response rates under the fixed-interval schedules were higher when the interreinforcer intervals approximated those produced under the fixed-ratio schedule, whereas the rates were lower when the interreinforcer intervals approximated those produced under the different-reinforcement-of-low-rate schedule. The present results demonstrate that the effects of behavioral history were under control of the interreinforcer intervals as discriminative stimuli.     

A foundation beam for studying morality from a personological point of view: Are individual differences in moral behaviors and thoughts consistent?

Morality is a topic of burgeoning scientific interest, and the relevance of personological factors to moral behavior has interdisciplinary implications for the social sciences, public policy, and philosophy. However, relatively little research has investigated the role of personological factors in moral life, perhaps because of lingering skepticism about the robustness of moral traits. The purpose of this paper is to determine whether morality is consistent across many occasions of everyday life, implying that personological factors play an important role in moral behavior. A novel method of assessing moral behaviors was developed and employed in two experience sampling studies (4075 total observations). Results showed that moral behavior is consistent in many different ways, suggesting that personological factors substantially impact moral life.     

Types of union participators over time: Toward a person-centered and dynamic model of participation

Previous research on union participation has been disjointed, with no clear consensus on the definition and nature of participation. Additionally, few studies have examined how participation changes over time, with those that have finding mixed results regarding its stability. We propose that these mixed and inconsistent findings are due largely to past research focusing on overall levels of participation, ignoring differences in how individuals participate. To remedy this, we adopted a person-centered approach to identify different types of union participators. Using a large sample of union members, we conducted latent transition analysis and found six union participator classes: high participators, leadership participators, formal union promoters, informal union promoters, silent supporters, and non-participators. In addition, we examined how individuals changed membership across two time points (separated by 6 years), antecedents of class membership (role tenure and union commitment), and outcomes (freerider intentions and actual financial contributions to the union's political action fund). The six classes differed uniquely, in terms of the ways people participate, changes in how people participate over time, what predicted class membership, and how class membership impacts two outcomes. The current study demonstrates that person-centered approaches can both clarify previous conflicting findings within the participation literature and predict meaningful outcomes.     

Effects of reinforcer probability, delay, and response requirements on the choices of rats and pigeons: possible species differences

In Experiment 1 with rats, a left lever press led to a 5-s delay and then a possible reinforcer. A right lever press led to an adjusting delay and then a certain reinforcer. This delay was adjusted over trials to estimate an indifference point, or a delay at which the two alternatives were chosen about equally often. Indifference points increased as the probability of reinforcement for the left lever decreased. In some conditions with a 20% chance of food, a light above the left lever was lit during the 5-s delay on all trials, but in other conditions, the light was only lit on those trials that ended with food. Unlike previous results with pigeons, the presence or absence of the delay light on no-food trials had no effect on the rats' indifference points. In other conditions, the rats showed less preference for the 20% alternative when the time between trials was longer. In Experiment 2 with rats, fixed-interval schedules were used instead of simple delays, and the presence or absence of the fixed-interval requirement on no-food trials had no effect on the indifference points. In Experiment 3 with rats and Experiment 4 with pigeons, the animals chose between a fixed-ratio 8 schedule that led to food on 33% of the trials and an adjusting-ratio schedule with food on 100% of the trials. Surprisingly, the rats showed less preference for the 33% alternative in conditions in which the ratio requirement was omitted on no-food trials. For the pigeons, the presence or absence of the ratio requirement on no-food trials had little effect. The results suggest that there may be differences between rats and pigeons in how they respond in choice situations involving delayed and probabilistic reinforcers.     

Development of Indirect Measures of Conscientiousness: Combining a Facets Approach and Network Analysis

Because indirect measures of personality self‐concepts such as the Implicit Association Test (IAT) allow tapping into automatic processes, they can offer advantages over self‐report measures. However, prior investigations have led to mixed results regarding the validity of indirect measures of conscientiousness. We suggest that these results might be due to a failure to consider the different facets of conscientiousness. These facets are of crucial importance because they are associated differentially with other psychobiological constructs and they are also characterized by different mechanisms. Therefore, focusing on facets while developing indirect measures of conscientiousness may improve the validity of such measures. In Study 1, we conducted a psycholexical investigation to develop one IAT for each conscientiousness facet. In Study 2, we examined the convergent and discriminant validities of each facet IAT in relation to self‐report measures, peer‐report measures and self‐report behavioural indicators, and we investigated differential associations of the conscientiousness facets with working memory capacity and self‐control. We employed network analysis as a novel approach to elucidate differential relationships involving personality facets. The results corroborated the convergent and discriminant validity of the conscientiousness facet IATs with self‐reports and showed that the conscientiousness facets were differentially associated with working memory capacity and with self‐control. Copyright © 2015 European Association of Personality Psychology     

内隐自尊与外显自尊的关系:多重内隐测量的视角

本研究以102名大学生为被试,从多重内隐测量的视角出发,运用内隐联想测验（IAT）、Go／No-go联想任务（GNAT）和外部情绪性Simon任务（EAST）三种实验程序对内隐自尊及其特性进行了测量和研究,同时运用结构方程建模对内隐自尊和外显自尊的结构关系进行了探讨。结果表明：（1）IAT、GNAT和EASI这三种基于反应时范式的内隐自尊测量方法是有效的,均能有效检测出内隐自尊效应,内隐自尊的特性表现为个体倾向于将自我与积极属性或事物相联,将他人与消极属性或事物相联;（2）内隐自尊与外显自尊是分离的结构,两者是相对独立的两个自我评价系统,支持内隐自尊和外显自尊的两维结构说;（3）双重态度模型和信息加工双过程模型两种理论模型都可以解释内隐自尊和外显自尊的分离现象。     

The search for dimensional structure differences between normality and abnormality: a statistical review of published data on personality and psychopathology

A statistical review of published data for 37 personality and psychopathology inventories was conducted to determine whether there are dimensional structure differences between clinical and nonclinical respondents. Correlation and factor-loading matrices from multiscale inventories and from specialized measures were tested for structural invariance across populations. There was relatively consistent evidence for high levels of similarity between normal and abnormal populations both in the number of factors that exist in the data matrices and in the factor patterns. The dimensional universes of normality and abnormality are apparently the same, at least according to data derived from contemporary assessment instruments. Categorical-taxonic differences between clinical and nonclinical populations, which were not examined, may nevertheless exist within contexts of dimensional structure similarity.     

Effects of a rival's perceived motives on constructive competition within organizations: A competitive dynamics perspective

Previous work on constructive competition has focused on competitors' motives and strategies; however, competition is an interactive process that is affected by both the competitor and the rival. Based on the competitive dynamics perspective and attribution theory, this study examines the impact of a perceived rival's motives on the constructiveness of competition. The results of a survey of 521 employees from 25 companies in the banking and insurance industry in Taiwan revealed that the perceptions of rivals' motives significantly affected the constructiveness of competition. By introducing the perspective of rival analysis to individual‐level competition, the present study provides a more comprehensive understanding of constructive competition within organizations.     

Coming together and remaining a part: Development of a group-as-a-whole compass. Part II

Group-as-a-whole theory is an attempt to explain the collaboration and synergy that results when patients share their care. The art and science of treating individuals within psychotherapy groups is enriched by an understanding of the unique mediums ³ through which a group comes into being and the more general domains within which it comes to be known. This paper continues the development of a group-as-a-whole compass, as an integration of extant models and theories (Ettin, 1996). The focus shifts from conceptual and spatial models to an exploration of the cultural and relational processes that make up whole-group functioning. The paper comes full circle with hypotheses drawn about how a psychotherapy group, as a holistic phenomenon, is composed and maintained.Private practice, East Brunswick, New Jersey.     

Bridging the gap between theory and model: a reflection on the balance scale task

At first glance, the two lead articles in this issue share little except the balance scale task, yet we view them as complementary rather than unrelated or contradictory. Our Reflection focuses on the individual strengths of the two lead articles and, to a greater extent, the potential power of their combined perspectives. Our general approach is to allow psychological theory to suggest a model of performance that can both evaluate specific theoretical claims and reveal important features of the data that had been previously obscured using conventional statistical analyses. Our guiding principle is that model, theory, and data all should be connected.     

From one room to the other: a story of contamination. The relationship between child and adult analysis

Does the analyst who works with both children and adults using ostensibly the same theoretical model perform similar mental operations in these two fields? The author suggests that child analysis is rooted in a different creative process from that of adults. Comparing the analysis of children to painting and that of adults to writing, and making use of the debate between Virginia Woolf and her sister Vanessa Bell on the relative merits of words and images, the author explores the psychoanalytic debate on the role of child analysis in the development of psychoanalytic theory and practice. Child analysis, initially regarded as an application of psychoanalysis, ended up acting as a catalyst for a true epistemological revolution in the 20th century through the work of Klein and Bion. Playing is not only an alternative medium to words for representing the unconscious but a different method for giving shape to representations through a specific creative process. The reverie which is born in the child analyst’s consulting room reproduces itself through the body’s actions during play, whereas in the adults’ consulting room the analyst’s capacity to dream presupposes the suspension of action. Child analysis, deploying a distinctive creative process that makes use of the body and serves itself of action in its development, may be said to rest on a similar creative process to that of figurative art. For this reason, the child analyst’s mind relates to objects in a different way, being in a more prolonged state of fusion with these as a result of ‘concentration of the body’. The significance of the unspeakable things that take place can often only be conceptualized in après‐coup. Although this difference in the development of the process suggests a significant distinction between the two ‘arts’ of child and adult analysis, the aesthetic sensitivity acquired through child analysis can be profitably used with adults, as will be demonstrated with the help of several clinical examples.