Work schedule and task factors in upper-extremity fatigue

The effects of operating height and the passage of time on the end-point performance of fine manipulative tasks that require high accuracy

Sustained shoulder abduction, which results from an inappropriate worktable height or tool shape and long task hours, leads to an accumulation of muscle fatigue and subsequent work-related injuries in workers. It can be alleviated by controlling the table height or ergonomic tool design, but workers who are doing some types of work that require a discomfortable posture, such as minimally invasive surgery, cannot avoid these situations. Loads to the shoulder joint or muscles result in several problems, such as muscle fatigue, deterioration of proprioception or changing movement strategies of the central nervous system, and these are critical to work that requires a high accuracy of the upper extremities. Therefore, in this paper, we designed and conducted an experiment with human participants to discuss how an inappropriate height of the work-table affects the task performance of workers who are performing a fine manipulative task that requires high accuracy of the end point. We developed an apparatus that can control the height and has four touch screens to evaluate the end-point accuracy with two different heights. Eighteen adults (9 women and 9 men) participated in the experiments, and the electromyography of their shoulder muscles, their movement stability, and task performance were measured for the analysis. We found that inappropriate height of a table brings about muscle fatigue, and time elapsed for conducting tasks accelerated the phenomenon. Task performance deteriorated according to increased fatigue, and improved movement stability is not enough to compensate for these situations.

Rostering in Air Traffic Control: A Narrative Review

Most Air Traffic Controllers (ATCOs) must cover uninterrupted work shifts for 24 h a day, seven days a week. The proper planning of a shift schedule requires consideration of at least three elements: the specific characteristics of the controller task, the physiological needs of the operator, and the definition of rest periods within rostering. We reviewed the literature for providing comprehensive guidance on the main requirements for the construction of a shift schedule for ATCOs. Our considerations are organized according to a rationale reflecting the most important criteria for the construction of the schedule: namely, the organization of rest periods conceptualized as intervals between cycles of shifts, intervals between individual shifts, and breaks within the shift. The suggested parameters could be used to construct shift schedules within a variation margin that depends on individual contexts of application.

An exploratory study comparing three work/rest schedules during simulated repetitive precision work

The pattern of work and rest can influence both physical fatigue and task performance in manual operations. However, there is relatively limited evidence regarding the influences of specific work/rest schedules in tasks requiring high repetitiveness and precision demands, along with relatively low exertion levels. Eighteen participants completed an exploratory study that simulated such tasks, to compare the effects of three distinct work/rest schedules (i.e. short frequent [short] and long infrequent breaks [long], and a self-selected schedule) on muscle fatigue, task performance (in terms of accuracy and speed), and preference. Schedules with long or self-selected breaks generally induced less muscle fatigue, compared with the short break condition. Participants preferred the self-selected condition the most and the long-break condition the least. The different schedules tested did not influence task performance. A self-selected schedule may be beneficial for repetitive precision task, to achieve a balance across muscle fatigue, task performance, and individual preference. Practitioner summary: Influences of three work/rest schedules (i.e. short and long breaks, and a self-selected schedule) on fatigue, performance, and preference were explored during repetitive precision tasks. Schedules with long or self-selected breaks induced less muscle fatigue and none of the three schedules influenced performance. A self-selected schedule was the most preferred.

Injuries associated with long working hours among employees in the US mining industry: risk factors and adverse outcomes

Objectives

The mining industry is increasingly adopting extended workdays of 10–12 hour shifts. Studies demonstrate that long work hours are associated with psychomotor impairments caused by fatigue and an increased risk of injury. However, studies involving miners remain limited. This analysis aimed to identify risk factors associated with long working hour injuries and to determine if long working hour incidents were associated with being killed or incidents involving multiple injured workers.

Methods

Data from US Mine Safety and Health Administration Part 50 reports, 1983–2015, were used to identify long working hour injuries, which were defined as incidents occurring nine or more hours after the start of a shift.

Results

A total of 52 206 injuries (9.6%) occurred during long working hours. The proportion of long working hour injuries increased from 5.5% of all injuries in 1983 to its peak in 2015 at 13.9% (p<0.001). Risk factors associated with long working hour injuries included irregular shift starts, being newly employed, employment by a contractor, metal/non-metal operations and mines with <100 employees. In two separate adjusted models, long working hour injuries were associated with a higher odds of death (adjusted OR [aOR]=1.32; 95% CI 1.18 to 1.48) and single incidents resulting in two or more workers injured (aOR=1.73; 95% CI 1.58 to 1.89).

Conclusions

Long working hour injuries were associated with a lack of routine, being new at the mine and specific mining activities. An international shift towards using contract labour and extended workdays indicates that injuries during long working hours will likely continue to grow as a problem in the mining industry.

Does work-induced fatigue accumulate across three compressed 12 hour shifts in hospital nurses and aides?

Fatigue-related impairments in the nursing workforce contribute to a multitude of health, safety, and economic consequences at the individual, organizational and societal levels. Long and compressed work schedules are commonly worked in the healthcare industry, but more research is needed to understand the cumulative effects of multiple work shifts on physiology-based performance outcomes in nurses. The purpose of this study was to compare the effects of a single nursing work shift versus three compressed (one every 24 hours) 12 hour shifts on performance-based fatigue in nurses and aides. Twenty-six fulltime hospital working nurses and aides (age = 36.1 ± 13.3 years) reported to the lab for testing before, immediately after working a single 12 hour shift, and after working three 12 hour shifts in a 72 hour period. Outcome measures included vigilance-based reaction time, lapses of attention, and muscle function assessments (lower and upper body muscle strength, explosive strength and vertical jump performance). All variables except hand grip strength showed a significant decline following the three work shifts. The psychomotor vigilance reaction time and lapses of attention variables also generally showed a significant decline from the end of shift one to the end of shift three, indicting an accumulation of fatigue in these metrics with increasing number of shifts worked. Muscle function variables responded early in the duty cycle, showing a significant decline after a single work shift, but did no further decline by the end of the third shift. These findings use objective measures to substantiate that fatigue impairments occur from working a single 12 hour shift, and in several instances, increase further with more successive work shifts. Caution should be employed by personnel and administrators with work schedules involving multiple compressed 12 hour shifts. Fatigue management strategies may be used to improve risks and consequences from fatigue-related mishaps, and this study reports several variables that appear sensitive to identifying and tracking fatigue in this population.

The Impact of a Rigorous Multiple Work Shift Schedule and Day Versus Night Shift Work on Reaction Time and Balance Performance in Female Nurses: A Repeated Measures Study

OBJECTIVE

The aim of this study was to determine the impact of a demanding work schedule involving long, cumulative work shifts on response time and balance-related performance outcomes and to evaluate the prevalence of musculoskeletal disorders between day and night shift working nurses.

METHODS

A questionnaire was used to identify the prevalence of past (12-month) and current (7-day) musculoskeletal disorders. Nurses worked three 12-hour work shifts in a 4-day period. Reaction time and balance tests were conducted before and after the work period.

RESULTS

The work period induced impairments for reaction time, errors on reaction time tasks, and balance performance, independent of shift type. Musculoskeletal symptom prevalence was high in workers of both work shifts.

CONCLUSIONS

Compressed work shifts caused performance-based fatigue in nurses. Reaction time and balance tests may be sensitive fatigue identification markers in nurses.

Effective Ergonomic Teaching for Positive Client Outcomes

Teaching and intervention are integral aspects of professional nursing practice. Numerous publications encourage the use of specific teaching intervention techniques, but few are validated by studies conducted to assess actual teaching behaviors of nurses who administer successful teaching intervention programs. This is a case study of one occupational health nurse who administers a highly effective ergonomic program for employees in a large urban hospital. Themes identified during observation of nurse and client interactions include mindfulness on the part of the nurse, respect for client autonomy, nurse effort, nurse accessibility, and professional distance. A consistent teaching process identified during observation consists of six steps: inquiry, invitation, assessment, synthesis, validation, and progression. This six step process is embedded within identified themes. Teaching and intervention methods identified in the study are a synthesis of caring behaviors and nursing process. This integrated method is entitled “Effective Teaching Through Unified Process and Caring Interpersonal Behavior.” It may represent a valid teaching and intervention method supporting compliance and positive client outcome when interacting with clients requiring ergonomic teaching and intervention.

Prevalência de dores musculoesqueléticas em motoristas de caminhão e fatores associados

Introdução:motoristas profissionais podem estar sujeitos a doenças musculoesqueléticas relacionadas às condições de trabalho.Objetivo:estimar a prevalência e identificar fatores associados à dor musculoesquelética na coluna vertebral, nos 12 meses anteriores à pesquisa, referida por motoristas de caminhão.Métodos:estudo transversal realizado em 2007 com todos os 460 motoristas do sexo masculino de uma empresa de transportes de carga. Utilizou-se questionário abordando fatores sociodemográficos, ocupacionais e de saúde. Análises de regressão logística univariada e múltipla foram utilizadas para verificar a associação entre o relato de dor musculoesquelética na coluna vertebral e os fatores estudados.Resultados:a prevalência de dor musculoesquelética referida foi de 53,5%, sendo mais prevalentes a dor na coluna vertebral (38,5%) e a dor na coluna lombar (28%). Sono de má qualidade, hábito de não cochilar, medo de ser assaltado, morrer, adoecer ou sofrer algum acidente durante o trabalho, e estresse, tensão ou fadiga por desconforto ao dirigir foram fatores associados às dores na coluna vertebral.Conclusão:constatou-se alta prevalência de lombalgia associada a estressores externos, como medo de acidentes e roubos, e a fatores ligados diretamente à organização do trabalho, como a ausência de pausas para cochilos e a restrição dos horários de sono, o que leva a sua má qualidade.

Differences in medical error risk among nurses working two- and three-shift systems at teaching hospitals: a six-month prospective study

Shift work, including night work, has been regarded as a risk factor for medical safety. However, few studies have investigated the difference in medical error risk between two- and three-shift systems. A total of 1,506 registered nurses working shifts at teaching hospitals participated in this study to evaluate the difference in medical error risk between two- and three-shift systems. After adjustment for potential confounding factors using a log Poisson generalized estimating equation model, the results showed significantly higher frequencies of perceived adverse events over 6 months in the three-shift than in the two-shift system, with estimated mean numbers of adverse events of 1.05 and 0.74, respectively. Shorter intervals after night shifts and greater frequency of night shifts in three-shift systems, which reduce the recovery time from night shift work, may be linked to increased medical errors by nurses.

Long working hours, safety, and health: toward a National Research Agenda

BACKGROUND

A significant and growing number of people work long hours. Research examining impacts is limited, but raises concerns about risks to the worker, the family, the employer, and the community. The purpose of this report, which is authored by the National Occupational Research Agenda (NORA) Long Work Hours Team, is to motivate and guide future research by proposing a framework for studying long work hours and discussing research gaps.

METHODS

The NORA Long Work Hours Team examined research reports and literature reviews, and gathered input from a conference on long work hours organized by the Team and faculty from University of Maryland.

RESULTS AND CONCLUSION

A framework is proposed for long work hours, including determinants, outcomes, and moderating factors of long work hours, suggesting that studies need to include more clear and complete descriptions of work schedules, worker characteristics, and the work environment, and need to consider a wider range of possible health, safety, social and economic outcomes for workers, families, employers, and the community. Additional studies are needed on vulnerable employee groups and those critical to public safety. More studies are also needed to develop interventions and test their effectiveness.

Possible broad impacts of long work hours

The paper summarizes research linking long work hours to a wide range of risks to workers, families, employers, and the community. The risks are theorized to stem from less time to recover from work, longer exposure to workplace hazards, and less time to attend to non-work responsibilities. Risks to workers include sleep deprivation, poor recovery from work, decrements in neuro-cognitive and physiological functioning, illnesses, adverse reproductive outcomes, and injuries. Risks to families include delayed marriages and child bearing, and obesity in children. Risks to employers include reduced productivity and increases in workers errors. Mistakes by fatigued workers have broad reaching impacts to the community: medical errors, automobile crashes with other drivers on the road, and industrial disasters that damage the environment.

Relationship of work schedules to gastrointestinal diagnoses, symptoms, and medication use in auto factory workers

BACKGROUND

Gastrointestinal (GI) complaints are common in shift workers. This study examines the relationship between work schedules and GI symptoms, medications, and diagnoses.

METHODS

In a cross-sectional survey of 343 US auto factory workers, four work schedule variables were examined: assigned shift, number of hours worked, number of night hours, and schedule variability. Multiple regression tested the relationship between GI outcomes and work schedule variables while controlling for covariates.

RESULTS

The evening shift was associated with more GI symptoms and GI diagnoses. Unexpectedly, more consistent work times were associated with having a GI diagnosis. As schedule variability increased the probability of GI medication use increased in low noise exposure.

CONCLUSION

Findings suggest that evening shift and widely varying work start and end times may increase risks for GI disturbances.

Work schedules and fatigue: a prospective cohort study

AIMS

(1) To describe the prevalence of fatigue among employees in different work schedules (day work, three-shift, five-shift, and irregular shift work); (2) to investigate whether different work schedules are related to increasing fatigue over time, while taking into account job title and job characteristics; and (3) to study fatigue among shift workers changing to day work.

METHODS

Data from nine consecutive four-monthly self administered questionnaires from the Maastricht Cohort Study on Fatigue at work (n = 12 095) were used with 32 months of follow up. Day and shift workers were matched on job title.

RESULTS

The prevalence of fatigue was 18.1% in day workers, 28.6% in three-shift, 23.7% in five-shift, and 19.1% in irregular shift workers. For three-shift and five-shift workers substantial higher fatigue levels were observed compared to day workers at baseline measurement. In the course of fatigue over the 32 months of follow up there were only small and insignificant differences between employees in different work schedules. However, among employees fatigued at baseline, fatigue levels decreased faster over time among five-shift workers compared to fatigued day workers. Shift workers changing to day work reported substantially higher fatigue levels prior to change, compared to those remaining in shift work.

CONCLUSIONS

Substantial differences in fatigue existed between day and shift workers. However, as no considerable differences in the course of fatigue were found, these differences have probably developed within a limited time span after starting in a shift work job. Further, evidence was found that fatigue could be an important reason for quitting shift work and moving to day work. Finally, in the relation between work schedules and fatigue, perceived job characteristics might play an important role.

The effect of working serial night shifts on the cognitive functioning of emergency physicians

STUDY OBJECTIVE

We sought to determine whether working 5 serial night shifts in the emergency department results in a decline in physician performance as measured with an intelligence test.

METHODS

This study compared the cognitive functioning of emergency physicians who worked the day shift (7 AM to 5 pm) with those who worked 5 consecutive night shifts (11 pm to 7 am). The Fluid Scale of the Kaufman Adolescent and Adult Intelligence Test (KAIT) was administered to 16 emergency medicine residents. Half of the residents (group A) were tested while working day shifts, and the other half (group B) were tested after working 5 consecutive night shifts. After a minimum interval of 2 months, the residents were retested in reverse order, with group A tested after working night shifts and group B tested while working day shifts.

RESULTS

A total of 16 emergency medicine residents were tested. A paired t test was used to determine whether day-shift KAIT scores are different from night-shift KAIT scores. The mean day-shift KAIT score was 119.1 (SD=7.7), and the mean night-shift KAIT score was 107.2 (SD=10.2). This difference was significant (mean difference=11.9; 95% confidence interval 7.0 to 16.8; P <.001), with the day-shift scores being statistically higher than the night-shift scores.

CONCLUSION

Working a series of 5 night shifts results in a substantial decline in cognitive performance in physicians working in the ED.