This dual-arm randomised study aims to test a multi-component intervention to reduce sedentary behaviour in a cohort of desk-based office workers.

There is increasing evidence to demonstrate that excessive and unhealthy patterns of sedentary behaviour can increase the risk of a range of health problems,independent to levels of physical activity. Increasingly, people are employed in low activity occupations with office workers being identified as one of the most sedentary roles. Small scale studies using prompts to remind office workers to stand have shown promising results, as well as representing a low-cost solution for employers. This study builds upon a recent pilot study investigating the impact of prompts delivered via Microsoft Outlook, on the sedentary behaviour of office workers.

Developed in accordance with the Medical Research Council framework for designing multi-component interventions this study utilises Social Cognitive Theory (SCT) as a theoretical basis. SCT describes the complex interaction between individuals and their environment. The influence of the office environment on sedentary behaviour is clearly illustrated by differences in people's sitting patterns inside and outside of working hours . Behavioural change techniques linked to the constructs of SCT have also been shown to have a positive impact on sedentary behaviour, namely education, goal setting and feedback. Participants in this study will therefore receive education on the benefits of breaking their sitting, tips on how to achieve this, and feedback on their baseline sitting behaviour. This study will test the impact of these techniques on sitting time and patterns, and also track their influence on the different constructs of SCT and individuals' readiness to change by measuring these at time points throughout the intervention. To address the fact that sitting at work may not be a conscious decision, but performed out of habit, half of participants will also receive prompts reminding them to stand. The same prompts will be used as in the pilot study, but the addition of an extra activity monitoring period will enable us to ascertain whether the impact of prompts diminishes during the intervention period.

This study will aim to recruit 60 desk-based office employees via email invitation. Volunteers will be screened using inclusion/exclusion criteria and asked to provide signed consent. Sitting will be de-emphasised in the participant information sheet, and other documentation used at recruitment, in order to minimise any impact on baseline activity measurements. Cluster randomisation will be used to split participants into two equal groups (Group 1 n=30, group 2 n=30) based on their physical location within the office(s) in order to minimise contamination between groups. Randomisation software will be used to allocate groups on www.randomisation.com. Baseline measurement for all participants will consist of completion of questionnaires and activity monitoring as follows:

1. Questionnaires:

   • Q1: Demographic data - to obtain basic information on participants
   • Q2: Stage of change questionnaire - measuring readiness to change
   • Q3: Social cognitive theory questionnaire - measuring key constructs of SCT

2. Activity monitoring:

   • Participants will be asked to wear a water-proofed activPAL activity monitor* on the front of their thigh for a period of 7 consecutive days (24 hours a day)

   • A brief diary will be completed for the same 7 days

     • The activPAL activity monitor has been validated for measuring and categorising sitting/lying, standing and walking using an acceleration signal from the thigh .

Following the collection of baseline data, all participants will attend a 1 hour education session during which they will receive a presentation outlining: the health problems associated with prolonged sedentary behaviour; how much sitting is recommended; feedback on their own baseline sitting behaviour; and tips on how to reduce and break up sedentary behaviour. They will be given a summary of their baseline activity data . Group 1 will then return to work as normal. Group 2 will receive an excel file to upload to Microsoft Outlook which will deliver prompts to break sitting at random times, once within an hour. The prompts will run for a period of 10 weeks and their content will be the same brief, positively framed messages that were evaluated favourably by participants in the pilot project. Measurements for all participants will be repeated as follows: Questionnaires Q2 and Q3 will be repeated after the education session and at 12 week follow-up; 1 week of activity monitoring will be repeated between weeks 2-4 of the intervention period, 8-10 of the intervention period, and at 12 week follow up.

Following final measurements, participants will be invited to one of a series of semi-structured focus groups to explore the feasibility, acceptability, meaningfulness and effectiveness of the intervention. Focus groups will be recorded using a digital voice recorder and transcribed.

Data will be treated as confidential, it will be anonymised, and stored securely in line with GCU's data protection policies. Electronic copies of the activity data will be kept for 10 years, alongside electronic and paper copies of the questionnaires and diaries and audio and transcribed accounts of the focus groups. Physical activity data and basic demographic data will also be kept on a password protected database on a secure server. The data held on the database will not be identifiable. The information collected may be used for further analysis by staff and students in the School of Health and Life Sciences at Glasgow Caledonian University at a later date. Access to data will be restricted and controlled by Dr Ben Stansfield, PGRT in the School of Health and Life Sciences, GCU. Individuals will not be identifiable from any reports published and the employer, JJML, will receive a report containing only amalgamated data.

: Each participant will receive a brief summary of their baseline activity data at the education session. In addition, at the end of the study they will be provided with an activity report, summarising their individual activity data for all 4 measurement periods. A report of amalgamated data, including the results of the focus groups, will be produced for JJML and this will also be made available to study participants. Furthermore, the results will be written up as a PhD thesis, published in appropriate academic journals and discussed in conference presentations.

Inclusion Criteria:

• Over 18 years of age
• Primarily engaged in sedentary, computer-based activities
• Access to Microsoft Outlook calendar

Exclusion Criteria:

• Workstation comprises of a standing desk
• Pre-existing health condition that prevents standing on a regular basis.