任务难度和时间压力在诱发WMSD中的作用

为探索职业性肌肉骨骼障碍(WMSD)的产生机制,并为开发其诊治指标提供依据,本研究通过两项实验,在低生理负荷情景下分别考察了任务难度和时间压力对肌肉活动(尤其是肩部斜方肌)和主观舒适性等的影响。结果发现:(1)除影响作业绩效外,任务难度和时间压力对斜方肌AEMG也有显著影响;(2)时间压力可导致心率上升;(3)任务难度和时间压力均会影响主观舒适感(尤其是眼、上臂的舒适感)。因此,任务难度和时间压力等心理社会因素可能是诱发颈-肩部等区域职业性肌肉骨骼障碍的重要变量。     

目标定向、自我效能感与主观幸福感的关系

以207名企业员工为研究对象,探讨了目标定向、自我效能感与主观幸福感的关系及自我效能感在目标定向和主观幸福感之间的中介作用。结果表明:学习目标定向、工作自我效能感和社交自我效能感均对主观幸福感有着显著的正向影响;主观幸福感对任务绩效有着显著的正向影响;同时,工作自我效能感在学习目标定向和主观幸福感之间起着完全中介作用。     

虚拟环境中临境感及其测量方法

虚拟环境（VE）中的临境感是用户感知身处VE而产生的一种主观体验,是评价VE的重要指标。VE临境感产生的基础在于个体VE某一特征的集中注意,其程度强弱在一定范围内取决于个体分配于VE的注意资源量,受诸如计算机技术设备等系统因素、表现为个体差异的用户因素以及人机对话过程中交互因素的影响。在此基础上本文从生理指标（生理测量法、心率变化和皮肤电阻变化）、行为指标（姿势变化和冲突条件下的刺激定位）、心理物理学（对比法和跨通道匹配法）、主观评价（WS-PQ、SUS-PQ、ITC-SOPI和直接主观评价法）和绩效衡量对VE临境感的测量方法进行总结和简单评价。     

心理韧性、孤独感、自我效能感预测老年人主观幸福感的优势分析

心理韧性、孤独感、自我效能感都会影响老年人的主观幸福感,但三者影响程度的相对大小尚不清楚。为考察其影响力的大小,本研究采用了优势分析的方法。选取心理韧性量表、UCLA孤独量表、一般自我效能感量表分别测量老年人的心理韧性、孤独感、自我效能感,主观幸福感量表、费城老年中心信心量表测量老年人主观幸福感。优势分析结果表明,孤独感对老年人主观幸福感的预测力大于心理韧性与自我效能感;心理韧性的预测力大于自我效能感。本研究提示减少孤独感是提升老年人主观幸福感的重要途径,而老年人的心理韧性和自我效能感对提升老年人主观幸福感有一定的作用。     

时间管理倾向与主观幸福感、工作倦怠的关系研究

以220名处级干部为研究对象,探讨了时间管理倾向与主观幸福感、工作倦怠的关系以及时间效能感在时间监控能力和主观幸福感、工作倦怠之间的中介作用.结果表明,时间管理倾向的时间价值感、时间监控能力和时间效能感三个维度与主观幸福感存在显著的正相关,与工作倦怠存在显著的负相关;主观幸福感与工作倦怠存在显著的负相关;时间效能感对时间监控能力与主观幸福感、工作倦怠之间具有部分中介作用,即时间监控能力既可以通过时间效能感影响主观幸福感和工作倦怠,也可以直接影响主观幸福感和工作倦怠.     

按键位置对手机键盘拇指操作绩效的影响

本研究假设对于同样的手机键盘操作任务,手机各按键的位置不同,在操作绩效上存在差异。该研究实验从被试的客观操作绩效(反应时和正确率)和主观满意度评价两方面证实了该假设的成立:在保持被试自然姿势操作手机键盘的情况下,各按键在手机键盘中的位置确实对操作工效有较大影响。     

自拍照编辑与女大学生主观幸福感的关系:积极反馈与自我概念的中介作用

该研究基于自我差异理论与自我验证理论探究自拍照编辑与女大学生主观幸福感的关系,以及积极反馈与自我概念的中介作用。采用自拍照编辑问卷、线上自拍照积极反馈问卷、一般自我概念量表、主观幸福感量表对550名女大学生进行调查研究,结果发现：（1）自拍照编辑的频率、积极反馈、自我概念、主观幸福感两两之间均呈显著正相关;（2）自拍照编辑的频率通过三条中介路径影响女大学生主观幸福感：通过积极反馈的中介作用;通过自我概念的中介作用;通过积极反馈及自我概念的链式中介作用;（3）积极反馈与自我概念在自拍照编辑的频率与女大学生主观幸福感的关系中起完全中介作用。研究结果进一步揭示自拍照编辑对主观幸福感影响的作用机制,为女大学生健康使用社交网站及社交网站的功能完善提供依据。     

朋友圈点赞与主观幸福感的关系:一个有中介的调节模型

研究旨在考察社交网站（微信朋友圈）中的积极反馈（点赞）与个体主观幸福感的关系，及其内在作用机制—孤独感的中介效应和生命意义体验的调节效应。采用朋友圈点赞频率问卷、生命意义体验量表、孤独感量表和主观幸福感量表对461名微信使用者进行研究。结果表明：（1）个体在朋友圈中获得点赞的频率可正向预测其主观幸福感。（2）生命意义体验对点赞频率与主观幸福感之间的关系具有调节效应。（3）这种调节效应以孤独感为中介变量。研究揭示了社交网站中的积极反馈与个体主观幸福感之间关系的内在机制及其个体差异，对避免社交网站中社会反馈的消极影响具有理论意义。     

主管支持感研究述评及展望

主管支持感是指员工对主管重视他们贡献、关心他们福祉的程度的总体看法。相关的实证研究表明主管支持感对员工的工作态度、工作绩效与行为以及心理压力与紧张等相关工作结果变量均存在一定的影响;而个体特征与工作特征方面的相关因素则对主管支持感具有一定的预测力。该文对组织行为学与人力资源管理领域有关主管支持感的相关研究进行了较为全面的总结,并在此基础上指出未来的研究有必要加强主管支持感的形成与干预机制等三方面问题的探讨     

领导者的希望和自我效能感对其主观幸福感的影响

该研究采用问卷调查法,检验领导者的希望和自我效能感对其主观幸福感的影响作用。通过对来自重庆市各县、市、区政府机关、公检法和事业行政单位的237名领导者进行调查,将搜集的数据进行层次回归分析、中介效应检验和优势分析,结果显示：希望和自我效能感是领导者的主观幸福感的显著正向预测变量;自我效能感在领导者的希望与其主观幸福感之间有显著的完全中介作用;增强领导者的希望与自我效能感水平对提升领导者的主观幸福感有显著的促进作用。     

The Influence of Contraction Types on the Relationship Between the Intended Force and the Actual Force

Abstract

It has been demonstrated that the intended force (subjective estimation of force) does not always match to actual force without external feedback. The purpose of this study was to compare the influence of ballistic and tonic contractions on the relationship between the intended and actual force. Subjects produced isometric force at requested percentages of their MVC (20, 40, 60 and 80%) based on subjective estimation of force under two conditions (tonic and ballistic conditions). The tonic condition was to maintain force production, whereas the ballistic condition was to produce force as fast as possible. As a result, the actual force amplitude, the coefficient of variance and EMG amplitude were larger under the ballistic contraction compared with the tonic condition, even the same intended force levels. These results suggest that different motor unit activity and control systems in the ballistic and tonic contractions could alter the relationship between the intended force and the actual force.     

Modulation of motor variability related to experimental muscle pain during elbow-flexion contractions

Experimental muscle pain typically reorganizes the motor control. The pain effects may decrease when the three-dimensional force components are voluntarily adjusted, but it is not known if this could have negative consequences on other structures of the motor system. The present study assessed the effects of acute pain on the force variability during sustained elbow flexion when controlling task-related (one-dimensional) and all (three-dimensional) contraction force components via visual feedback. Experimental muscle pain was induced by bolus injection of hypertonic saline into m. biceps brachii, and isotonic saline was used as control. Twelve subjects performed sustained elbow flexion at different levels of the maximal voluntary contraction (5–30% MVC) before, during, and after the injections. Three-dimensional force components were measured simultaneously with surface electromyography (EMG) from elbow flexors and auxiliary muscles. Results showed that force variability was increased during pain compared to baseline for contractions using one-dimensional feedback (P < .05), but no significant differences were found for three-dimensional feedback. During painful contractions (1) EMG activity from m. trapezius was increased during contractions using both one-dimensional and three-dimensional feedback (P < .05), and (2) the complexity of EMG from m. triceps brachii and m. deltoid was higher for the three-dimensional feedback (P < .05). In conclusion, the three-dimensional feedback reduced the pain-related functional distortion at the cost of a more complex control of synergistic muscles.     

Reorganised motor control strategies of trunk muscles due to acute low back pain

This study assessed how the low back motor control strategies were affected by experimental pain. In twelve volunteers the right m. longissimus was injected by hypertonic and isotonic (control) saline. The pain intensity was assessed on a visual analog scale (VAS). Subjects were seated on a custom-designed chair including a 3-dimensional force sensor adjusted to the segmental height of T1. Electromyography (EMG) was recorded bilaterally from longissimus, multifidus, rectus abdominis, and external oblique muscles. Isometric trunk extensions were performed before, during, and after the saline injections at 5%, 10%, and 20% of maximum voluntary contraction force. Visual feedback of the extension force was provided whereas the tangential force components were recorded. Compared with isotonic saline, VAS scores were higher following hypertonic saline injections (P < .01). Experimental low back pain reduced the EMG activity bilaterally of the rectus abdominis muscles during contractions at 10% and 20% MVC (P < .01) although force accuracy and tangential force variability was not affected. Increased variability in the tangential force composition was found during pain compared with the non-painful condition (P < .05). The immediate adaptation to pain was sufficient to maintain the quality of the task performance; however the long-term consequence of such adaptation is unknown and may overload other structures.     

Sensory feedback in the learning of a novel motor task

The role of different forms of feedback is examined in learning a novel motor task. Five groups of ten subjects had to learn the voluntary control of the abduction of the big toe, each under a different feedback condition (proprioceptive feedback, visual feedback, EMG feedback, tactile feedback, force feedback). The task was selected for two reasons. First, in most motor learning studies subjects have to perform simple movements which present hardly any learning problem. Second, studying the learning of a new movement an provide useful information for neuromuscular reeducation, where patients often also have to learn movements for which no control strategy exists. The results show that artificial sensory feedback (EMG feedback, force feedback) is more powerful than "natural" (proprioceptive, visual, and tactile) feedback. The implications of these results for neuromuscular reeducation are discussed.     

Sensory Feedback in the Learning of a Novel Motor Task

The role of different forms of feedback is examined in learning a novel motor task. Five groups of ten subjects had to learn the voluntary control of the abduction of the big toe, each under a different feedback condition (proprioceptive feedback, visual feedback, EMG feedback, tactile feedback, force feedback). The task was selected for two reasons. First, in most motor learning studies subjects have to perform simple movements which present hardly any learning problem. Second, studying the learning of a new movement can provide useful information for neuromuscular reeducation, where patients often also have to learn movements for which no control strategy exists. The results show that artificial sensory feedback (EMG feedback, force feedback) is more powerful than “natural” (proprioceptive, visual, and tactile) feedback. The implications of these results for neuromuscular reeducation are discussed.     

The treatment of nocturnal bruxism using contingent EMG feedback with an arousal task

Nocturnal electromyographic (EMG) recordings of masseter muscle activity were performed before and after treatment on 10 heavy bruxism subjects. Treatment consisted of giving the subjects an auditory feedback signal during sleep which occurred when they clenched with moderate force. Each subject additionally had to perform an arousal task every time the signal occurred. Nine of 10 subjects demonstrated a significantly decreased EMG activity using a contingent auditory feedback signal, combining it with an arousal task.     

Control of oscillatory force tasks: Low-frequency oscillations in force and muscle activity

Force variability during steady force tasks is strongly related to low-frequency oscillations (<0.25 Hz) in force. However, it is unknown whether low-frequency oscillations also contribute to the variability of oscillatory force tasks. To address this, twelve healthy young participants (21.08 ± 2.99 years, 6 females) performed a sinusoidal force task at 15% MVC at two different frequencies (0.5 and 1 Hz) with isometric abduction of the index finger. We recorded the force from the index finger and surface EMG from the first dorsal interosseous muscle and quantified the following outcomes: 1) trajectory variability and accuracy; 2) power spectrum of force and EMG bursting below 2 Hz; 3) power spectrum of the interference EMG from 4 to 60 Hz. The trajectory variability and error significantly increased from 0.5 to 1 Hz task (P < 0.01). Increased force oscillations <0.25 Hz contributed to greater trajectory variability and error for both the 0.5 and 1 Hz oscillatory task (R² > 0.33; P < 0.05). The <0.25 Hz oscillations in force were positively associated with greater power in the <0.25 Hz for EMG bursting (R² > 0.52; P < 0.01). The modulation of the interference EMG from 35 to 60 Hz was a good predictor of the <0.25 Hz force oscillations for both the 0.5 Hz task and 1 Hz task (R² > 0.66; P < 0.01). These results provide novel evidence that, similar to steady contractions, low-frequency oscillations of the motor neuron pool appear to be a significant mechanism that controls force during oscillatory force tasks.     

Comparative effectiveness of patterned biofeedback vs meditation training on EMG and skin temperature changes

This study examined whether a low arousal, relaxation pattern of frontalis EMG decreases and peripheral skin temperature increases could be attained more effectively through biofeedback or meditation training. Thirty female subjects, ranging in age from 21 to 59, were randomly assigned to one of three groups: patterned biofeedback, clinically standardized meditation or control. Prior to training, subjects were administered the EPI. Each subject was seen weekly for seven sessions. Subjective experiences and time spent practising at home were also recorded. Repeated measures ANCOVA's performed on the EMG and skin temperature means indicated that the meditation group showed significantly lower EMG levels at the end of treatment than the control group. No group had significant temperature increases nor were there any significant differences in practice time. The biofeedback group had difficulty in patterning the two feedback signals simultaneously. Extraverts in the control group had the highest EMG levels. The most positive subjective reports came from subjects in the meditation group. Meditation offers a viable alternative as a relaxation procedure, requiring little time to learn and devoid of any performance criteria levels.     

Computer automation of biofeedback training

A computer-automated system has been developed for implementing response-contingent training strategies in EMG biofeedback-assisted relaxation training. An on-line minicomputer is programmed to (1) monitor progress within a training session as reflected in EMG signals; (2) compare the progress data with criteria set by the operator at the beginning of the session; and (3) on the basis of these comparisons, periodically adjust feedback gain (sensitivity) and make changes in the within-session training sequence. The system is designed to allow various adaptive training strategies to be software programmable. One of these strategies, a “shaping” procedure commonly employed in EMG biofeedback training, gradually increases the degree of relaxation necessary to produce the desired feedback signal by increasing feedback gain as the subject gets better at relaxing. Implementation of the shaping procedure is described as an illustration of system function. Current system development is guided by principles from adaptive testing and teaching systems to make more of the feedback training process adaptive in function.     

Delayed sensory feedback in the learning of a novel motor task

Summary Generally the therapeutical effect of EMG feedback is viewed in terms of the immediate contiguity between response and information. According to this view any feedback delay would deteriorate the result. In this article the validity of this notion has been investigated. Three groups of normal subjects were required to perform a difficult movement under three feedback conditions: immediate EMG feedback, delayed EMG feedback, and a control (no EMG feedback) condition. The results indicated a significant difference between the EMG feedback groups and the control condition. However, no such difference was found between the immediate and delayed feedback conditions. The results suggested that the immediacy of the feedback is not the main factor in EMG feedback, but the specificity of the information.This study was supported by Grant no. 15-35-03 from the Netherlands Organization for the Advancement of Pure Research