Sitting, standing and moving time
Sitting, standing, and moving time will be objectively measured via an activPAL3 activity monitor (PAL Technologies Limited, Glasgow, UK; default settings). This monitor continuously records the precise beginning and ending of each bout of sitting or lying (here termed sitting), standing, and stepping at a variety of speeds, and the estimated MET-hours expended during those bouts. Previous studies have shown this device to be valid, reliable and responsive [
54‐
57]. Waterproofing of the device will be achieved by first inserting it into a nitrile finger cote and then wrapping the device in waterproof
Opsite Flexifix
(™)
(Smith & Nephew).Thereafter, the activPAL3 will be secured to the anterior mid-line of the right thigh, about a third of the way down from the hip, using hypoallergenic adhesive material (
Hypafix®, BSN medical). Additional hypoallergenic patches will be given to participants for the adhesive materials to be changed as required. Participants will be requested to wear the activPAL3 activity monitor for 24 hours per day, for seven consecutive days at each assessment period (baseline, 3-, and 12-months). At each assessment, participants will also concurrently wear the tri-axial GT3X + Actigraph activity monitor (ActiGraph, Pensacola, Florida). Participants will be asked to wear this activity monitor during waking hours only (except for water-based activities) for the seven-day assessment period. The accelerometer is positioned over the right hip via an elastic belt. The raw accelerometer data will be collected at 30Hz.
Daily logs (self-completed) will be used to record wake and sleep times, work hours (defined as time spent at the primary DHS study worksite), and any device removal greater than 15 minutes. Periods of work time spent not at the primary worksite (i.e. working from home) will also be recorded. A customized SAS 9.3 (SAS Institute Inc., Cary, NC) program, utilising both the activity monitor and log data, will be used to generate sitting, standing, and moving outcomes at work and overall, with the primary outcome being sitting time at work (measured by activPAL3). Consistent with the intervention message, prolonged sitting is defined as time accrued in sitting bouts at least 30 minutes in length. The number of transitions between sitting and standing will also be measured. The GT3X + activity monitor will be used to differentiate time spent in light-intensity physical activity and MVPA.
Survey measures
Socio-demographic characteristics Based on questions used in the Australian Diabetes, Obesity and Lifestyle (AusDiab) study [
58], information relating to age, gender, ethnicity, marital status, and education will be obtained (baseline assessment only).
Physical health history data Musculoskeletal health will be measured using the 27-item Nordic Musculoskeletal Questionnaire, modified to refer to the last seven days and the last three months (instead of 12 months) [
59]. This questionnaire includes items on 'trouble’ in numerous body parts as well as the capacity to perform normal activities in the presence of any 'troubles’, and has been shown to be repeatable and sensitive to change [
60]. Eye-strain will be assessed with three items used in a previous ergonomics intervention study, where it was shown to have high internal consistency [
61]. A checklist, adapted from previous work that has demonstrated good internal consistency [
62], will assess physical health symptoms commonly associated with stress such as fatigue, headaches, digestive problems and sleep quality. Current smoking status (including at work) and history of diabetes and hyperlipidaemia will also be collected.
Self-reported physical activity and sitting time Participants will be asked to estimate the total time spent watching TV/videos during the week and on weekends; average daily sitting time during the week and on weekends; and the proportion of sitting, standing, walking and physically demanding tasks during a typical work day in the previous seven days [
63,
64].
Work outcomes Productivity, presenteeism, and absenteeism will be obtained for each assessment period using internal DHS measures and validated questionnaires [
65‐
67]. The Health and Work Questionnaire (HWQ) has six sub-scales (productivity, concentration/focus, supervisor relations, non-work satisfaction, impatience/irritability), with internal consistency scores ranging from alpha = 0.72 to 0.96 [
65]. In addition, a total HWQ score will be calculated (alpha = 0.81) [
65]. Self-reported work performance will be assessed on a 9-item, 10-point scale [
66]. Performance items include amount and quality of work accomplished, meeting deadlines, frequency of errors, taking responsibility, creativity, getting along with others, dependability and overall performance [
66]. Presenteeism and absenteeism will be assessed using the proprietary Work Limitations Questionnaire (WLQ), which examines the frequency of difficulty to perform specific job tasks [
67].
Work history and environment Questions will assess perceptions of the work environment and current work patterns including: length of tenure; job classification; FTE level; desk/workstation utilisation; environmental satisfaction; and, frequency and duration of working with colleagues as well as perceived adequacy of space(s) for such interactions. Previously validated instruments [
35,
66,
68] and items developed specifically for this study (Additional file
6: Figure S6) will be used.
Dietary intake will be measured using the 20-item Fat & Fibre Behaviour Index which asked about eating habits over the previous month. This questionnaire has previously been used in our randomised controlled trials and has been shown to be sensitive to change [
69].
Mediators Potential mediators of change have been conceptualised under the three levels of intervention (organisational, environmental, individual). All mediators will be assessed in both groups at all assessments via the on-line questionnaire. The organisational mediator to be assessed will be the site-specific team champion’s attitudes and knowledge (scales described below). At the environmental level, participants will be asked to report the frequency of use of their workstation in the past month on a 5-point Likert scale (from 'never’ to 'very often’). Individual-level mediators will include the following theoretical constructs: preference for sitting and standing at work; knowledge; barrier self efficacy; perceived behavioural control; perceived organisational social norms; as well as frequency of use of self-regulation strategies and other individual-level intervention strategies. There are no existing measures for these individual-level constructs in relation to workplace sitting; therefore, where possible, we have adapted scales from the more developed physical activity literature or otherwise a study-specific scale was created. All of the scales were pilot tested in our previous workplace sitting intervention [
20] and the psychometric properties (internal consistency and test-retest reliability) of these scales can be found in Additional file
7: Table S1. Preference will be measured across two items on a 5-point scale indicating the proportion of work time participants preferred to be sitting or standing (ranging from 'none of the time’ to '80-100% of time’). Knowledge of key intervention messages will be assessed across five items (e.g., “Sitting for most of the time at work is bad for my health”); on a 5-point Likert scale ('strongly disagree to 'strongly agree’). The barrier self efficacy scale has been adapted from an existing scale [
70] and will assess nine items referring to specific barriers to reducing workplace sitting (e.g., confidence to 'stand up during meetings at work, even though no one else was’), which will be assessed on a 5-point Likert scale ('not at all confident’ to 'very confident’). Perceived behavioural control will be examined across five items (e.g., 'It is my choice whether I stand up or sit during a meeting with colleagues at work’) on a 5-point Likert scale ('strongly disagree to 'strongly agree’). Organisational social norms will be assessed in eight items (e.g., 'My workplace is committed to supporting staff choices to stand or move more at work’) on a 5-point Likert scale ('strongly disagree to 'strongly agree’). Self-regulation will be examined across 10 items on a 5-point Likert scale ('never’ to 'very often’), adapted from an existing scale for physical activity [
71] and will include self-regulation strategies targeted in the intervention (e.g., “recorded my sitting or standing at work in a written record”). In addition, frequency of use of intervention-specific strategies is also assessed across nine items on a 5-point Likert scale ('never’ to 'very often’). The complete set of questions is provided in Additional file
8: Figure S7.
Moderators These will be assessed at baseline in both study groups. Potential moderators will be grouped as: demographic (e.g., age, gender, BMI, health status); work-related characteristics (e.g., position, hours worked per week, main work tasks); office environment characteristics assessed as part of the baseline workplace descriptive audit (e.g., office layout); and behavioural characteristics (e.g., MVPA, sitting outside work hours).
Adverse events The adverse events that the participant attributes as “study-related” will be collected at each follow-up assessment in the intervention group only. Health care utilisations (number of visits to GPs and allied health care professionals) pertaining to the adverse event (s) will also be measured as part of the economic evaluation (Additional file
9: Figure S8).
Quality of life will be measured using the validated Australian Quality of Life Survey (AQoL-8D) which consists of eight separately scored dimensions (Independent Living, Happiness, Mental Health, Coping, Relationships, Self Worth, Pain, Senses) totalling 35 items [
72].