Effect of Periodic Voluntary Interventions on Trapezius Activation and Fatigue During Light Upper Limb Activity.

OBJECTIVE: The effects of diverse periodic interventions on trapezius muscle fatigue and activity during a full day of computer work were investigated. BACKGROUND: Musculoskeletal disorders, including trapezius myalgia, may be associated with repeated exposure to prolonged low-level activity, even during light upper-extremity tasks including computer work. METHODS: Thirty healthy adults participated in a study that simulated two 6-hour workdays of computer work. One workday involved imposed periodic passive and active interventions aimed at disrupting trapezius contraction monotony (Intervention day), whereas the other workday did not (Control day). Trapezius muscle activity was quantified by the 3-dimensional acceleration of the jolt movement of the acromion produced by electrically induced muscle twitches. The spatio-temporal distribution of trapezius activity was measured through high-density surface electromyography (HD-EMG). RESULTS: The twitch acceleration magnitude in one direction was significantly different across measurement periods (p = 0.0156) on Control day, whereas no significant differences in any direction were observed (p > 0.05) on Intervention day. The HD-EMG from Intervention day showed that only significant voluntary muscle contractions (swing arms, Jacobson maneuver) induced a decrease in the muscle activation time and an increase in the spatial muscle activation areas (p < 0.01). CONCLUSION: Disruption of trapezius monotonous activity via brief voluntary contractions effectively modified the ensuing contraction pattern (twitch acceleration along one axis, active epochs reduction, and larger spatial distribution). The observed changes support an associated reduction of muscle fatigue. APPLICATION: This study suggests that disruptive intervention activity is efficient in reducing the impact of trapezius muscle fatigue.

Evidence for the Effectiveness of Feedback from Wearable Inertial Sensors during Work-Related Activities: A Scoping Review.

Background: Wearable inertial sensor technology (WIST) systems provide feedback, aiming to modify aberrant postures and movements. The literature on the effects of feedback from WIST during work or work-related activities has not been previously summarised. This review examines the effectiveness of feedback on upper body kinematics during work or work-related activities, along with the wearability and a quantification of the kinematics of the related device. Methods: The Cinahl, Cochrane, Embase, Medline, Scopus, Sportdiscus and Google Scholar databases were searched, including reports from January 2005 to July 2021. The included studies were summarised descriptively and the evidence was assessed. Results: Fourteen included studies demonstrated a 'limited' level of evidence supporting posture and/or movement behaviour improvements using WIST feedback, with no improvements in pain. One study assessed wearability and another two investigated comfort. Studies used tri-axial accelerometers or IMU integration (n = 5 studies). Visual and/or vibrotactile feedback was mostly used. Most studies had a risk of bias, lacked detail for methodological reproducibility and displayed inconsistent reporting of sensor technology, with validation provided only in one study. Thus, we have proposed a minimum 'Technology and Design Checklist' for reporting. Conclusions: Our findings suggest that WIST may improve posture, though not pain; however, the quality of the studies limits the strength of this conclusion. Wearability evaluations are needed for the translation of WIST outcomes. Minimum reporting standards for WIST should be followed to ensure methodological reproducibility.

Curved Versus Flat Monitors: Interactive Effects of Display Curvature Radius and Display Size on Visual Search Performance and Visual Fatigue.

OBJECTIVE: The aim of this study is to examine the interactive effects of display curvature radius and display size on visual search accuracy, visual search speed, and visual fatigue. BACKGROUND: Although the advantages of curved displays have been reported, little is known about the interactive effects of display curvature radius and size. METHOD: Twenty-seven individuals performed visual search tasks at a viewing distance of 50 cm using eight configurations involving four display curvature radii (400R, 600R, 1200R, and flat) and two display sizes (33″ and 50″). To simulate curved screens, five flat display panels were horizontally arranged with their centers concentrically repositioned following each display curvature radius. RESULTS: For accuracy, speed, and fatigue, 33″-600R and 50″-600R provided the best or comparable-to-best results, whereas 50″-flat provided the worst results. For accuracy and fatigue, 33″-flat was the second worst. The changes in the horizontal field of view and viewing angle due to display curvature as well as the association between effective display curvature radii and empirical horopter (loci of perceived equidistance) can explain these results. CONCLUSION: The interactive effects of display curvature radius and size were evident for visual search performance and fatigue. Beneficial effects of curved displays were maintained across 33″ and 50″, whereas increasing flat display size from 33″ to 50″ was detrimental. APPLICATION: For visual search tasks at a viewing distance of 50 cm, 33″-600R and 50″ 600R displays are recommended, as opposed to 33″ and 50″ flat displays. Wide flat displays must be carefully considered for visual display terminal tasks.

Supporting Surgical Teams: Identifying Needs and Barriers for Exoskeleton Implementation in the Operating Room.

OBJECTIVE: The objective of this study was to identify potential needs and barriers related to using exoskeletons to decrease musculoskeletal (MS) symptoms for workers in the operating room (OR). BACKGROUND: MS symptoms and injuries adversely impact worker health and performance in surgical environments. Half of the surgical team members (e.g., surgeons, nurses, trainees) report MS symptoms during and after surgery. Although the ergonomic risks in surgery are well recognized, little has been done to develop and sustain effective interventions. METHOD: Surgical team members (n = 14) participated in focus groups, performed a 10-min simulated surgical task with a commercial upper-body exoskeleton, and then completed a usability questionnaire. Content analysis was conducted to determine relevant themes. RESULTS: Four themes were identified: (1) characteristics of individuals, (2) perceived benefits, (3) environmental/societal factors, and (4) intervention characteristics. Participants noted that exoskeletons would benefit workers who stand in prolonged, static postures (e.g., holding instruments for visualization) and indicated that they could foresee a long-term decrease in MS symptoms with the intervention. Specifically, raising awareness of exoskeletons for early-career workers and obtaining buy-in from team members may increase future adoption of this technology. Mean participant responses from the System Usability Scale was 81.3 out of 100 (SD = 8.1), which was in the acceptable range of usability. CONCLUSION: Adoption factors were identified to implement exoskeletons in the OR, such as the indicated need for exoskeletons and usability. Exoskeletons may be beneficial in the OR, but barriers such as maintenance and safety to adoption will need to be addressed. APPLICATION: Findings from this work identify facilitators and barriers for sustained implementation of exoskeletons by surgical teams.

Does Reducing Sedentarity With Standing Desks Hinder Cognitive Performance?

OBJECTIVE: The goal of this study was to determine if using a standing desk would affect the productivity of workers, based on the type of work they perform. BACKGROUND: Standing desks are a promising new health intervention in the workplace, but users and employers often require more specific recommendations related to productivity, such as the type of work that is more suited for the standing desk. METHOD: Thirty-seven young and healthy adults performed eight cognitive tasks in a 2 × 2 × 2 within-subject design of the following independent variables: posture (sitting/standing), task difficulty (easy/hard), and input device (computer mouse/tactile screen) in a counterbalanced order. RESULTS: Our results revealed that using a standing desk had no negative effect on performance or perception, but it did lead to increased brain activity in the alpha band for the parietal region (ß = 0.186, p = .001). CONCLUSION: We conclude that users of standing desks can freely stand for any level of task difficulty for work that involves working memory. However, more research is needed to generalize these results to other types of cognitive abilities and prolonged use of standing desks. APPLICATION: Our results simplify recommendations for workers as they do not need to worry about the type of work they are performing when using a standing desk.

Barriers to the Adoption of Wearable Sensors in the Workplace: A Survey of Occupational Safety and Health Professionals.

OBJECTIVE: To gather information on the (a) types of wearable sensors, particularly personal activity monitors, currently used by occupational safety and health (OSH) professionals; (b) potential benefits of using such technologies in the workplace; and (c) perceived barriers preventing the widespread adoption of wearable sensors in industry. BACKGROUND: Wearable sensors are increasingly being promoted as a means to improve employee health and well-being, and there is mounting evidence supporting their use as exposure assessment and personal health tools. Despite this, many workplaces have been hesitant to adopt these technologies. METHODS: An electronic survey was emailed to 28,428 registered members of the American Society of Safety Engineers (ASSE) and 1,302 professionals certified by the Board of Certification in Professional Ergonomics (BCPE). RESULTS: A total of 952 valid responses were returned. Over half of respondents described being in favor of using wearable sensors to track OSH-related risk factors and relevant exposure metrics at their respective workplaces. However, barriers including concerns regarding employee privacy/confidentiality of collected data, employee compliance, sensor durability, the cost/benefit ratio of using wearables, and good manufacturing practice requirements were described as challenges precluding adoption. CONCLUSION: The broad adoption of wearable technologies appears to depend largely on the scientific community's ability to successfully address the identified barriers. APPLICATION: Investigators may use the information provided to develop research studies that better address OSH practitioner concerns and help technology developers operationalize wearable sensors to improve employee health and well-being.

Errors Using Observational Methods for Ergonomics Assessment in Real Practice.

OBJECTIVE: The degree in which practitioners use the observational methods for musculoskeletal disorder risks assessment correctly was evaluated. BACKGROUND: Ergonomics assessment is a key issue for the prevention and reduction of work-related musculoskeletal disorders in workplaces. Observational assessment methods appear to be better matched to the needs of practitioners than direct measurement methods, and for this reason, they are the most widely used techniques in real work situations. Despite the simplicity of observational methods, those responsible for assessing risks using these techniques should have some experience and know-how in order to be able to use them correctly. METHOD: We analyzed 442 risk assessments of actual jobs carried out by 290 professionals from 20 countries to determine their reliability. RESULTS: The results show that approximately 30% of the assessments performed by practitioners had errors. In 13% of the assessments, the errors were severe and completely invalidated the results of the evaluation. CONCLUSION: Despite the simplicity of observational method, approximately 1 out of 3 assessments conducted by practitioners in actual work situations do not adequately evaluate the level of potential musculoskeletal disorder risks. APPLICATION: This study reveals a problem that suggests greater effort is needed to ensure that practitioners possess better knowledge of the techniques used to assess work-related musculoskeletal disorder risks and that laws and regulations should be stricter as regards qualifications and skills required by professionals.

Employee acceptance of wearable technology in the workplace.

Wearable technology has many industrial applications. Optimal use adherence and outcomes largely depend on employee acceptance of the technology. This study determined factors that predict employee acceptance of wearables. An online survey of 1273 employed adults asked about demographics, job and organizational characteristics, experience with and beliefs about wearables, and willingness to use wearables. Use cases focused on workplace safety elicited the highest acceptance. An employee's performance expectancy and their organizational safety climate were common predictors of acceptance across use cases. Positive past experiences coincided with involving employees in choosing the device and adequately informing them about data use. Organizations intending to implement wearable technology should (a) focus its use on improving workplace safety, (b) advance a positive safety climate, (c) ensure sufficient evidence to support employees' beliefs that the wearable will meet its objective, and (d) involve and inform employees in the process of selecting and implementing wearable technology.

Inhibiting the Physiological Stress Effects of a Sustained Attention Task on Shoulder Muscle Activity.

OBJECTIVE: The objective of this study was to investigate if a breathing technique could counteract the effects of hyperventilation due to a sustained attention task on shoulder muscle activity. BACKGROUND: The trend towards higher levels of automation in industry is increasing. Consequently, manufacturing operators often monitor automated process for long periods of their work shift. Prolonged monitoring work requires sustained attention, which is a cognitive process that humans are typically poor at and find stressful. As sustained attention becomes an increasing requirement of manufacturing operators' job content, the resulting stress experienced could contribute to the onset of many health problems, including work related musculoskeletal disorders (WRMSDs). METHODS: The SART attention test was completed by a group of participants before and after a breathing intervention exercise. The effects of the abdominal breathing intervention on breathing rate, upper trapezius muscle activity and end-tidal CO2 were evaluated. RESULTS: The breathing intervention reduced the moderation effect of end-tidal CO2 on upper trapezius muscle activity. CONCLUSIONS: Abdominal breathing could be a useful technique in reducing the effects of sustained attention work on muscular activity. APPLICATION: This research can be applied to highly-automated manufacturing industries, where prolonged monitoring of work is widespread and could, in its role as a stressor, be a potential contributor to WRMSDs.