Dechristian Barbieri

The ability of non-computer tasks to increase biomechanical exposure variability in computer-intensive office work

Postures and muscle activity in the upper body were recorded from 50 academics office workers during 2 hours of normal work, categorised by observation into computer work (CW) and three non-computer (NC) tasks (NC seated work, NC standing/walking work and breaks). NC tasks differed significantly in exposures from CW, with standing/walking NC tasks representing the largest contrasts for most of the exposure variables. For the majority of workers, exposure variability was larger in their present job than in CW alone, as measured by the job variance ratio (JVR), i.e. the ratio between min–min variabilities in the job and in CW. Calculations of JVRs for simulated jobs containing different proportions of CW showed that variability could, indeed, be increased by redistributing available tasks, but that substantial increases could only be achieved by introducing more vigorous tasks in the job, in casu illustrated by cleaning. Practitioner Summary: Too little exposure variation is a general concern in computer-intensive office work. This study shows, using a novel metric, that available NC tasks can, indeed, increase variation compared to doing only CW, but also that a substantial increase in variation requires introducing more vigorous tasks such as cleaning.

Sit–Stand Tables With Semi-Automated Position Changes: A New Interactive Approach for Reducing Sitting in Office Work

OCCUPATIONAL APPLICATIONS Sit–stand tables with semi-automated position changes were developed in order to remind users to switch regularly between sitting and standing postures during office work. Tests of the system showed good user compliance: Desk usage patterns were sustained during the entire 2 months following intervention. Users reported the new system did not interfere with their work, that it impacted their perception of health and well-being positively, and that they would have liked to continue using the system beyond the intervention period. This could thus be a promising intervention to ensure adequate use of sit–stand desks and sustain their use over time. TECHNICAL ABSTRACT Background: Introducing sit–stand tables has been proposed as an initiative to decrease sedentary behavior among office workers and thus reduce risks of negative cardiometabolic health effects. However, ensuring proper and sustainable use of such tables has remained a challenge for successful implementation. Purpose: Assess a new system developed to promote and sustain the use of sit–stand tables. Methods: The system was programmed to change the position of the table between “sit” and “stand” positions per a regular preset pattern if the user agreed to the system-generated prompts prior to each change. The user could respond to the system-generated prompts by agreeing, refusing, or postponing the changes by 2 minutes. We obtained user compliance data when this system was programmed to a schedule of 10 minutes of standing after every 50 minutes of sitting. Compliance was investigated among nine office workers who were offered the semi-automated sit–stand table for 2 months. Results: The system issued 12 to 14 alerts per day throughout the period. Mean acceptance rates ranged from 75.0% to 82.4%, and refusal rate ranged from 11.8% to 10.1% between the first and eighth weeks of intervention (difference not statistically significant). During the first week after introduction, the table was in a standing position for a mean of 75.2 minutes—increasing slightly to 77.5 minutes in the eighth week. Conclusions: Since the workers were essentially sitting down before the table was introduced, these results suggest that the system was well accepted, and led to an effective reduction of sitting during working hours. Users also reported that the system contributed positively to their health and well-being, without interrupting their regular work, and that they would like to continue using the sit–stand table even beyond the 2-month period as part of their regular work. Compliance beyond 2 months of use, however, needs to be verified.

Comparison of Sedentary Behaviors in Office Workers Using Sit-Stand Tables With and Without Semiautomated Position Changes:

Objective: We compared usage patterns of two different electronically controlled sit-stand tables during a 2-month intervention period among office workers. Background: Office workers spend most of their working time sitting, which is likely detrimental to health. Although the introduction of sit-stand tables has been suggested as an effective intervention to decrease sitting time, limited evidence is available on usage patterns of sit-stand tables and whether patterns are influenced by table configuration. Method: Twelve workers were provided with standard sit-stand tables (nonautomated table group) and 12 with semiautomated sit-stand tables programmed to change table position according to a preset pattern, if the user agreed to the system-generated prompt (semiautomated table group). Table position was monitored continuously for 2 months after introducing the tables, as a proxy for sit-stand behavior. Results: On average, the table was in a “sit” position for 85% of the workday in both groups; this percentage did not change significantly during the 2-month period. Switches in table position from sit to stand were, however, more frequent in the semiautomated table group than in the nonautomated table group (0.65 vs. 0.29 hr-1; p = .001). Conclusion: Introducing a semiautomated sit-stand table appeared to be an attractive alternative to a standard sit-stand table, because it led to more posture variation. Application: A semiautomated sit-stand table may effectively contribute to making postures more variable among office workers and thus aid in alleviating negative health effects of extensive sitting.

Musculoskeletal disorders and psychosocial risk factors among workers of the aircraft maintenance industry.

During the recent decades Brazil has experienced an exponential growth in the aviation sector resulting in an increasing workforce. The aircraft maintenance industry stands out, where the workers have to handle different kind of objects. The aim of this study was to evaluate psychosocial indicators as well as musculoskeletal symptoms and disorders among aircraft maintenance workers. One hundred and one employees were evaluated (32.69 ± 8.25 yr, 79.8 ± 13.4 kg, and 1.75 ± 0.07 m). Musculoskeletal symptoms and disorders were assessed through the Nordic Musculoskeletal Questionnaire (NMQ) and a standardized physical examination. The Job Content Questionnaire (JCQ) and the Utrecht Work Engagement Scale (UWES) were applied to evaluate psychosocial indicators. Results of the NMQ indicate the lower back as the most affected body region. On the other hand, the physical examination has shown clinical diagnosis of shoulder disorders. Neck, upper back and ankle/foot were also reported as painful sites. Most of workers have active work-demand profile and high work engagement levels. We suggest that musculoskeletal symptoms may be related to high biomechanical demand of the tasks performed by workers, what must be further investigated.

Can experience modulate handler responses to boxes designed to decrease musculoskeletal load

Abstract Biomechanical load during the handling of commercial (cardboard box with and without cut out) and non-commercial boxes (cardboard box with a retreat on the bottom edges), on experienced compared to inexperienced subjects was evaluated. Thirty-seven inexperienced and 21 experienced workers handled all boxes at shoulder and ground levels. Biomechanical load on upper limb was investigated through posture and electromyography (EMG) recordings. Comfort and effort were assessed immediately after each handling. In general, experienced workers had low range of motion. On the other hand, EMG was similar between both groups, except when non-commercial boxes were handled in non-favourable heights. Comfort was higher when a non-commercial box was handled versus a commercial one, regardless of the group. Both groups had a lower biomechanical load when handling the non-commercial boxes compared to the commercial ones. However, experienced workers did not have the same advantage as inexperienced subjects when handling those new boxes. Practitioner Summary: Box designs favouring intuitive hand coupling and more efficient postures have potential to reduce the risk of upper-limb musculoskeletal disorders in inexperienced subjects. However, ergonomist has to deal with workers on different levels of experience. Results of this study can support the development of effective recommendations for the working context.

Psychosocial indicators among aircraft maintenance workers with and without neck and shoulder musculoskeletal symptoms.

In the aircraft maintenance industry, most of workers performs manual handling tasks of different materials, varying from small objects up to large pieces of the aircraft. It can increase the occurrence of work-related musculoskeletal disorders (WMSDs), which are strongly associated with high physical demands required by the task. Moreover, psychosocial demands are considered as risk factors for musculoskeletal disorders in both the upper limbs and lumbar spine. Thus, the objective of this study was to assess psychosocial indicators among aircraft maintenance workers according to the presence of neck and shoulder musculoskeletal symptoms. Eighty workers of an aircraft maintenance company were evaluated (32.69 ± 8.25 years, 79.8 ± 13.4 kg, 175 ± 7 cm). According to physical examination, 50 workers were classified as asymptomatic (AS - 4.1 ± 3.17 positive signs) whilst 30 workers were classified as symptomatic (SS - 26.72 ± 11.44 positive signs). AS and SS have shown similar profile of demand (p = 0.62), control (p = 0.66) and social support (p = 0.74) according to the Job Content Questionnaire. However, the groups are different when considering work engagement variables. In general, SS have higher scores than AS (p < 0.05).

Variation in upper extremity, neck and trunk postures when performing computer work at a sit-stand station

Sit-stand tables are introduced in offices to increase variation in gross body posture, but the extent to which upper body posture variation is also affected has not previously been addressed. Neck, trunk, and upper arm postures (means and minute-to-minute variances) were determined during periods of sitting and standing from 24 office workers using sit-stand tables to perform computer work. Posture variability resulting from different temporal compositions of sitting and standing computer work was then predicted for the neck, trunk and upper arm by simulations. Postural variability during computer work could be increased up to three-fold when 20-60% of the work was performed standing (i.e. 40-80% performed sitting), compared to performing computer work only sitting. The exact composition of sit-stand proportions leading to maximum variability, as well as the potential size of the increase in variability, differed considerably between workers. Guidelines for sit-stand table use should note these large inter-individual differences.

The effect of sit-stand workstations to decrease sedentariness in office work tests of 2 systems with and without automatic reminders

Sedentary behaviors in office workers has become a major public health concern and several initiatives have been proposed to break up sedentary behavior patterns during the performance of computer-intensive office work (Neuhaus et al., 2014; Toomingas et al., 2012). Among such initiatives, the use of sit-stand workstations has been suggested to be one of the most promising by recent reviews (Commissaris et al., 2015). However, there still is only limited scientific evidence showing how effective sit-stand workstations are, in reducing sedentary behaviors and also documentation of their sustainability of use in studies of regular office work (i.e. as the “newness” of the system wears off, with time since introduction). This study aimed to document user behaviors and compare the use of two sit-stand workstation based interventions among two groups of administrative office workers: an “autonomous” group in which these workstations were introduced following some general ergonomic guidelines, and another “feedback-system” group in which the sit-stand tables were furnished with an automatic reminder system: users were prompted to accept, delay or refuse pre-programmed changes in table position, and if they accepted, the system automatically raised the table to a high (i.e. standing) position. This system was programmed for 10 minutes of standing after every accumulated 50 minutes of the table being in a low (i.e. sitting) position. In addition to documenting average use of the two sit-stand workstations, the sustainability of their use over two continuous months since their introduction was also studied. The results averaged over two months of usage of the two interventions showed that the percentage (%) sitting time was 87.4 (84.9-89.2) and 84.0 (83.5-85.4) on average (P=0.001), and the frequency of switches between sitting and standing was 0.3 (0.2-0.3) per hour and 0.7 (0.6-0.7) per hour (P=0.001) in the autonomous and feedback-system groups respectively. These usage behaviors were found to be stable over the entire 2 months of use in both groups. Thus, the sit-stand table system integrated with the automatic reminder system led to more reduction in sitting time and more switches in posture between sitting and standing as compared to the traditional sit-stand table, and behaviors of both groups were seen to be sustained over the 2-month intervention period. In conclusion, a semi-automated sit-stand table may thus offer an effective contribution to making sedentary behavior patterns more variable among office workers, and thus aid in preventing negative health effects associated with prolonged sitting times.