Robert A. Henning

Frequent short rest breaks from computer work: effects on productivity and well-being at two field sites

Computer operators at two work sites (n = 73, n = 19) were prompted to take three 30-s and one 3-min break from computer work each hour in addition to conventional rest breaks. Some operators were asked to perform stretching exercises during the short breaks. Mood state and musculoskeletal discomfort were assessed at each work site over a 2- or 3-week baseline period and a 4- or 6-week treatment period, respectively. Operator productivity measures were obtained from company records. Operators complied with about half of the added breaks but favoured 3-min breaks over 30-s breaks. No improvement in productivity or well-being was found at the larger work site. At the smaller work site, productivity, eye, leg and foot comfort all improved when the short breaks included stretching exercises. These results provide evidence that frequent short breaks from continuous computer-mediated work can benefit worker productivity and well-being when the breaks integrate with task demands.

Microbreak length, performance, and stress in a data entry task

The effects of brief rest pauses on performance and well-being were evaluated for a highly repetitive, data entry task. Experienced data entry operators (N = 20) performed the task in a two-day experiment in a simulated office environment. Each day was divided into six, 40-min work periods. Subjects took a brief rest pause at the workstation (microbreak) in the middle of each work period. Subjects were instructed to terminate this microbreak when ready to resume work. Keystroke rate, error rate, correction rate, heart rate and heart rate variability were scored for each half of the work period. In addition, mood states before and during the work period were assessed. Microbreaks were found to average 27.4 s in duration. High ratings of fatigue and boredom during the work period were associated with longer microbreaks, suggesting that the break period was self-adjusted relative to mood state. In addition, correction rate and heart rate were lower following long microbreaks, implying that the degree of recovery was linked to the length of the microbreak. Comparison of keystroke output and correction rate before and after the microbreak, however, revealed that performance worsened after the microbreak, suggesting that subjects terminated microbreaks before complete recovery could occur.

A Conceptual Framework for Integrating Workplace Health Promotion and Occupational Ergonomics Programs

Musculoskeletal, cardiovascular, and mental health are all associated with the physical and psychosocial conditions of work, as well as with individual health behaviors. An integrated approach to workplace health-promotion programs should include attention to the work environment, especially in light of recent findings that work organization influences so-called lifestyle or health behaviors. Macroergonomics provides a framework to improve both physical and organizational features of work and, in the process, to empower individual workers. The Center for the Promotion of Health in the New England Workplace (CPH-NEW) is a research-to-practice effort examining the effectiveness of worksite programs that combine occupational safety and health—especially /sc>ergonomics—with health promotion, emphasizing the contribution of work organization to both. Two intervention studies are underway in three different sectors: health care, corrections, and manufacturing. Each study features participatory structures to facilitate employee input into health goal-setting, program design and development, and evaluation, with the goal of enhanced effectiveness and longer-term sustainability.

The fragility of intergroup relations: Divergent effects of delayed audiovisual feedback in intergroup and intragroup interaction

Intergroup interactions between racial or ethnic majority and minority groups are often stressful for members of both groups; however, the dynamic processes that promote or alleviate tension in intergroup interaction remain poorly understood. Here we identify a behavioral mechanism—response delay—that can uniquely contribute to anxiety and promote disengagement from intergroup contact. Minimally acquainted White, Black, and Latino participants engaged in intergroup or intragroup dyadic conversation either in real time or with a subtle temporal disruption (1-s delay) in audiovisual feedback. Whereas intergroup dyads reported greater anxiety and less interest in contact after engaging in delayed conversation than after engaging in real-time conversation, intragroup dyads reported less anxiety in the delay condition than they did after interacting in real time. These findings have theoretical and practical implications for understanding intergroup communication and social dynamics and for promoting positive intergroup contact.

Workplace health protection and promotion through participatory ergonomics: an integrated approach.

A multidisciplinary team of researchers at the Center for the Promotion of Health in the New England Workplace (CPH-NEW) developed an evidencebased approach to address three recognized challenges to workplace programs designed to improve employee health: establishing employee ownership, integrating with work organization, and sustainability. The two main innovations being introduced in combination were (1) integrating traditional workplace health protection (e.g., ergonomics, industrial hygiene) with health promotion (e.g., assisting workers in improving health behaviors) and (2) introducing a bottom-up participatory model for engaging employees in innovative iterative design efforts to enhance both components of this integrated program. In the program, which was modeled after participatory ergonomics programs, teams of workers engage in the iterative design of workplace interventions to address their prioritized health concerns with the support of a multilevel steering committee. The integrated approach being tested can complement existing worksite safety and health initiatives and promote organizational learning, with expected synergistic effects.

Social-physiological compliance as a determinant of team performance.

A cybernetic model of behavior predicts that team performance may depend on physiological compliance among participants. This laboratory study tested if compliance in electrodermal activity (EDA), heart rate or breathing in two-person teams (N=16) was predictive of team performance or coordination in a continuous tracking task simulating teleoperation. Visual contact among participants was manipulated. Physiological compliance was scored with weighted coherence and cross correlation. Separate multiple regression analyses revealed that the task completion time was predicted by coherence measures for EDA and heart, but only at a trend level for breathing. Task completion time was also predicted by heart cross correlation. Team tracking error was predicted by coherence measures for EDA, heart and breathing, and also heart cross correlation. While social-visual contact did not have an impact, physiological compliance was predictive of improved performance, with coherence robust over all three physiological measures. Heart cross correlation showed the strongest predictive relationships. These results provide evidence that physiological compliance among team members may benefit team performance. While further study is needed, physiological compliance may someday provide a needed tool for the study of team work, and an objective means to guide the ergonomic design of complex sociotechnical systems requiring a high degree of team proficiency.

Differences in frequency of finger tremor in otherwise asymptomatic mercury workers.

Tremor was measured from the index finger during low force, position holding in 18 control subjects and 18 battery workers with low level exposure to mercury. All workers were asymptomatic on clinical neurological examination. No differences were found in average tremor amplitudes between the groups, but statistically significant abnormalities in tremor frequency distribution existed. Tremor power spectra in the group of mercury workers were shifted toward the higher frequencies and compressed into narrow frequency peaks. These results suggest that measurements of finger tremor that evaluate the frequency distribution can produce a higher diagnostic yield than traditional visual clinical judgement. The findings also confirm other reports that currently permitted exposures to mercury are associated with subtle but distinctive differences in tremor accompanying voluntary movement.

Participatory ergonomics as a model for integrated programs to prevent chronic disease.

Objective: To describe the value of participatory methods for achieving successful workplace health promotion (WHP) programming, and specifically the relevance of participatory ergonomics (PE) for the Total Worker Health (TWH) initiative. Methods: We review the concept of macroergonomics, and how PE is embedded within that framework, and its utility to modern WHP approaches such as “social health promotion.” We illustrate these constructs in practice within TWH. Results and Conclusions: Participatory ergonomics is relevant to WHP because (1) psychosocial stress contributes to individual health behaviors as well as chronic diseases; (2) job stress cannot be addressed without employee involvement in hazard identification and solutions; (3) the interaction of multiple levels within an organization requires attention to needs and constraints at all levels, just as the social-ecological model addresses higher-level determinants of and constraints on individual behaviors.

The Intervention Design and Analysis Scorecard: a planning tool for participatory design of integrated health and safety interventions in the workplace.

Objective: As part of a Research-to-Practice Toolkit development effort by the Center for the Promotion of Health in the New England Workplace, to develop and test a structured participatory approach for engaging front-line employees in the design of integrated health protection and promotion interventions. Methods: On the basis of a participatory ergonomics framework, the Intervention Design and Analysis Scorecard (IDEAS) provides a stepwise approach for developing intervention proposals, including root cause analysis and setting evaluation criteria such as scope, obstacles, and cost/benefit trade-offs. The IDEAS was tested at four diverse worksites with trained facilitators. Results: Employees were able to develop and gain management support for integrated interventions at each worksite. Conclusions: The IDEAS can be used effectively by front-line employees to plan integrated interventions in a program dedicated to continuous improvement of employee health protection/promotion and Total Worker Health.

Continuous feedback to promote self-management of rest breaks during computer use

Abstract Short rest breaks at regular intervals can reduce musculoskeletal discomfort and the risk of repetitive strain injury during intensive computer work, but may seriously disrupt some tasks. As an alternative, two laboratory experiments tested if application of ergonomic principles of feedback control could improve worker self-management of discretionary rest breaks. Undergraduate typists ( N = 31, N = 30) entered lines of randomized words for about 1 h. Typists received scheduled breaks unless their discretionary breaks reached a target level of 30 s every 10 min. Typists in treatment conditions received continuous feedback indicating how their discretionary breaks compared to the target level, but typists in control conditions did not. Feedback in one experiment was task-integrated to reduce distractions. Typists in the feedback conditions controlled discretionary breaks better than controls, and also responded favorably to the continuous feedback. Typists receiving task-integrated feedback reported less task disruption and back discomfort than controls. Mood and cardiac response were unaffected in both studies, but error rates were lower in the feedback condition of one experiment. These results indicate that computer users can utilize continuous feedback about rest break behavior to improve self management of discretionary rest breaks, with no untoward effects on performance, well-being, or user acceptance.