Walking Speed and Global Cognition: Results from the OKLAHOMA Study

ABSTRACT

Executive functioning and processing speed have been related to physical functioning in non-demented, elderly samples; however, the relationship between walking speed and global cognition has not been examined. Six hundred and seventy-five community dwelling older adults were enrolled through their primary care physicians. Walking speed was assessed on a 50-foot course at usual pace. Global cognition was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Total Scale score. After adjusting for age, gender, and education, there was a strong inverse relationship between walking speed and global cognition, with slower walkers performing worse on the cognitive measures, faster walkers performing better on the cognitive measures, and the intermediate walkers performing in the middle. In these older adults, global cognition was related to walking speed.     

工作家庭冲突的初步研究

工作家庭冲突是一种特殊类型的角色交互冲突 ,它对于了解人的胜任特征模型和提高人力管理的效率有重要的意义。本研究通过在银行、科研单位和高新技术企业进行的有关工作家庭冲突的调查结果表明 ,较之家庭—工作冲突 ,工作—家庭冲突能较好预测员工的工作压力 ,它通过工作压力间接地对工作满意感起作用 ,女性员工的工作态度更容易受到工作—家庭冲突的影响。     

言语想象的神经机制

言语想象不仅在大脑预处理机制方面起到重要的作用,还是目前脑机接口领域研究的热点。与正常言语产生过程相比,言语想象的理论模型、激活脑区、神经传导路径等均与其有较多相似之处。而言语障碍群体的言语想象、想象有意义的词语和句子时的脑神经机制与正常言语产生存在差异。鉴于人类言语系统的复杂性,言语想象的神经机制研究还面临一系列挑战,未来研究可在言语想象质量评价工具及神经解码范式、脑控制回路、激活通路、言语障碍群体的言语想象机制、词语和句子想象的脑神经信号等方面进一步探索,为有效提高脑机接口的识别率提供依据,为言语障碍群体的沟通提供便利。     

Self-reported walking difficulty and knee osteoarthritis influences limb dynamics and muscle co-contraction during gait

Knee osteoarthritis (OA) gait is characterized by simultaneous flexor and extensor use, or co-contraction. Co-contraction can stabilize and redirect joint forces. However, co-contraction can push and pull on the femur and tibia that exacerbate OA symptoms and make walking difficult. Such movements are quantifiable by limb dynamics (i.e., linear acceleration and jerk); thus, this study examines limb dynamics and its relationship with co-contraction and OA related walking difficulty.Three groups of age-and-sex-matched subjects with and without OA and walking difficulty (N = 13 per group) walked with electromyography (EMG) on the knee extensors and flexors and inertial measurement units (IMUs) at the femur and tibia. We calculated co-contraction from antagonistic EMG signals and linear acceleration and its derivative jerk from IMUs. We determined group differences using one-way ANOVAs, nonparametric equivalence, and effect sizes, and main and interaction effects of walking difficulty with regression modeling.Medium effect sizes and differences for femoral acceleration (d = 0.64; P = .02) and jerk (d = 0.51; P = .01) were observed between with and without knee OA. Medium to large effect sizes (r = 0.33 to 0.51 and d = 0.81 to 0.97) and differences (P = .01 to 0.05) for tibial acceleration and jerk were obsevered between with and without walking difficulty. Walking difficulty moderated the relationship between tibial jerk and co-contraction (p < .05).Tibial jerk differences were observed based on walking difficulty. The significant interaction effect suggested that walking difficulty explained the relationship between limb dynamics and co-contraction. Perhaps co-contraction levels used by those with knee OA and no walking difficulty are optimal as compared to those with walking difficulty.     

Influence of anterior load carriage on lumbar muscle activation while walking in stable and unstable shoes

Load carriage can be harmful for workers, and alternative interventions to reduce back pain while walking and carrying loads are necessary. Unstable shoes have been used to improve balance and reduce back pain, but it is unknown whether walking wearing unstable shoes while carrying loads anteriorly causes excessive trunk extensors muscle activation. The aim of this study was to investigate the effects of different shoe types and anterior load carriage on gait kinematics and lumbar electromyographic (EMG) activity. Fourteen adults that predominantly walk or stand during the work day were asked to walk with and without carrying 10% of body mass anteriorly while wearing regular walking shoes (REG) and unstable shoes (MBT). The effects of shoe type, load carriage, and shoe × load interactions on the longissimus thoracis (LT) and iliocostalis lumborum (IC) EMG, stride duration, and stride frequency were assessed. MBT shoes induced a significant increase in LT (44.4 ± 35%) and IC EMG (33.0 ± 32%, p < .005), while load carriage increased LT (58.5 ± 41%) and IC EMG (55.1 ± 32%, p < .001). No significant shoe × load interaction was found (p>.05). However, walking wearing MBT shoes while carrying loads induced a 46 ± 40% higher EMG activity compared to walking wearing MBT shoes without load carriage. No effects of shoes or load carriage were found on stride duration and stride frequency. It was concluded that walking wearing MBT shoes and carrying 10% of total body mass induced greater activation of trunk extensors muscle compared to these factors in isolation, such a combination may not influence gait patterns.     

Introduction to the special issue on the intersection of professional selling and service

As organizational operations continue to evolve in response to increasing customer demands, frontline research has begun to consider how traditionally separate organizational functions may be complementary to firm performance. Specifically, as sales and service activities become increasingly intertwined within the frontline role, this special issue explores how the sales and service functions interact within an organization. The articles contained in this special issue consider the interaction of sales and service with respect to customer, employee, and firm outcomes. After introducing evolving thought in the area, we provide an overview of five articles that make up this special issue. We conclude by offering additional areas of research.     

Learning in the brain–computer interface: insights about degrees of freedom and degeneracy from a landscape model of motor learning

In this paper, we examine the role of degrees of freedom and their degeneracy in learning in the brain–computer interface paradigm. Though the traditional notion of degrees of freedom in motor learning gave emphasis to muscle and joint activity, the broader concept of dimensions of behavior is relevant to brain–computer interface learning where there is no muscle activity. The role of degeneracy in the dimensions of brain activity is proposed to enhance learning through robustness to stability loss and adaptability in the search for new stable states. Principles for the application of augmented information for learning to coordinate and control the degenerate degrees of freedom in the brain–computer interface are outlined.