Understanding the role of breaks from sitting on musculoskeletal symptoms in desk-based workers

Abstract

Musculoskeletal disorders are conditions that affect musculoskeletal (MSK) tissues (e.g., muscles, bones) and are characterised by an inflammatory process that leads to pain and discomfort in the affected area. According to the Global Burden of Diseases (2019) study, musculoskeletal disorders are amongst the top twenty causes of years lived with disability at all ages. These disorders also contribute to a high economic burden on health systems worldwide and lead to job absenteeism due to incapacity to work.

Sedentary behaviour (SB) has been associated with a high risk for all-cause mortality, type 2 diabetes, cancer, and the development of MSK symptoms. Office workers are particularly at risk to develop these health problems due to the high prevalence of SB. Thus, strategies to reduce SB are necessary to decrease health problems in this population. Breaks from sitting are non-sedentary activities that take place between sedentary bouts. Research evidence has suggested that reducing SB with breaks from sitting provides benefits on cardio-metabolic, vascular, and cognitive health. However, evidence of the effects of breaks from sitting on MSK outcomes has been limited to mainly self-reported evidence.

Due to the COVID-19 pandemic, there was a sudden shift for many workers from working in the office to work from home (WFH). There is limited understanding of SB when WFH, including evidence of the impact of breaks from sitting on MSK symptoms. The overall aim of this thesis was to expand knowledge of the role of breaks from sitting as a strategy to reduce MSK symptoms and occupational SB in office workers. Three studies were conducted to address this aim.

The first study was a systematic review planned to address the limited evidence of the effects of breaks from sitting on device assessed MSK outcomes. Two objectives were followed. First, synthesise evidence of the effectiveness of breaks from sitting on device assessed MSK spinal outcomes. Second, compare those findings with self-reported MSK spinal outcomes if available. Twelve studies (n=12) were included in this review. Studies were divided into acute-single session interventions and medium to long-term interventions (2 weeks to 3 months). Three main types of breaks were identified: stretching, standing, and walking breaks. When divided by break type, it was evident that stretching breaks were the most effective break to improve device assessed and self-reported MSK spinal outcomes in acute single session and medium to long-term settings. Breaks from sitting seemed to be a useful strategy to reduce MSK symptoms in sedentary workers in office settings. With workers increasingly WFH, it was important to understand what the role of breaks from sitting was in the home environment.

The second study was a cross-sectional quantitative study planned considering the shift for workers to increased WFH, and the favourable effects of breaks from sitting from the first study. The study aimed to explore differences in MSK symptom prevalence between groups defined by occupational sitting, breaks from sitting, and chair settings. Objectives were to describe occupational sitting, breaks from sitting, chair settings and MSK symptoms in University of Edinburgh staff WFH. Participants (n=332, age range 18-61; female 73%) sat for most of their working day (89% of the workday) and took 1.3±1.4 breaks per hour, duration 5.3±7.0 minutes. A high prevalence (93%) of MSK symptoms was indicated in staff. Chair mean scores (3.5±1.2) indicated that staff chair settings while WFH represented a low risk of pain development. In relation to MSK symptoms, it was found that staff with the longest occupational sitting (over 8 hours per day) had a significantly higher prevalence of MSK symptoms, but there were no significant effects of the number and duration of breaks and chair settings on MSK symptoms prevalence in staff WFH. Understanding why staff engaged in prolonged SB was key to reducing this behaviour, and subsequently reducing MSK symptoms prevalence.

The third study was a qualitative study planned considering the elevated prevalence of SB and MSK symptoms in University of Edinburgh staff from the second study. This study aimed to understand the factors influencing SB and breaks from sitting in University of Edinburgh staff with MSK symptoms WFH. The study was built using two theoretical models, the COM-B model, and the Theoretical Domains Framework. University of Edinburgh staff (n=17; age 47.1±9.4; female 82%) were interviewed on MS Teams. The Framework method was chosen to analyse data from the interviews. The main findings indicated that participants had the psychological and physical capability to reduce their sitting. Unexpectedly, the presence of MSK symptoms appeared to not be a barrier for staff to break up their sitting while WFH. Barriers to reducing sitting at home were mapped to the physical and social opportunity, automatic and reflective motivation constructs. Additionally, the most important barrier for participants to reduce their sitting was their current workload and the various barriers associated with this. There are various challenges to reducing SB while WFH, but is essential to target workload management for this population to reduce their SB.

This thesis has advanced knowledge on the role of breaks from sitting as a strategy to reduce MSK symptoms and SB prevalence in two work environments (office and home). Thesis findings suggest that breaks from sitting, specifically stretching breaks, are a useful strategy to reduce MSK spinal symptoms at the office. However, it appears the number and duration of breaks do not affect MSK symptoms prevalence in workers WFH. On the other hand, engaging in occupational SB of over eight hours does affect this prevalence. Nevertheless, MSK symptom prevalence did not seem to affect SB at home, whereas workload was the most influential factor to remain sedentary. Changes around workload are necessary for desk-based workers with MSK symptoms to reduce their SB while WFH, and subsequently reduce their MSK symptoms. Future research should focus on exploring the direct effects of breaks on MSK symptoms during working hours at the office and the home environment.