A workplace-based intervention to increase levels of daily physical activity: the Travel to Work cluster RCT
Authors: Audrey Suzanne , Fisher Harriet , Cooper Ashley , Gaunt Daisy , Metcalfe Chris , Garfield Kirsty , Hollingworth William , Procter Sunita , Gabe-Walters Marie , Rodgers Sarah , Gillison Fiona , Davis Adrian , Insall Philip 
Published: June 2019

Background
There may be opportunities for working adults to accumulate recommended physical activity levels (≥ 150 minutes of moderate-intensity physical activity in bouts of ≥ 10 minutes throughout the week) during the commute to work. Systematic reviews of interventions to increase active transport indicate that studies are predominantly of poor quality, rely on self-report and lack robust statistical analyses.

Objectives
To assess the effectiveness, cost and consequences of a behavioural intervention to increase walking during the commute to work.

Design
A multicentre, parallel-arm, cluster randomised controlled trial incorporating economic and process evaluations. Physical activity outcomes were measured using accelerometers and GPS (Global Positioning System) receivers at baseline and the 12-month follow-up.

Setting
Workplaces in seven urban areas in south-west England and south Wales.

Participants
Employees (n = 654) in 87 workplaces.

Interventions
Workplace-based Walk to Work promoters were trained to implement a 10-week intervention incorporating key behaviour change techniques.

Main outcome measures
The primary outcome was the daily number of minutes of moderate to vigorous physical activity (MVPA). Secondary outcomes included MVPA during the commute, overall levels of physical activity and modal shift (from private car to walking). Cost–consequences analysis included employer, employee and health service costs and consequences. Process outcomes included barriers to, and facilitators of, walking during the daily commute.

Results
There was no evidence of an intervention effect on MVPA at the 12-month follow-up [adjusted difference in means 0.3 minutes, 95% confidence interval (CI) –5.3 to 5.9 minutes]. The intervention cost was on average, £181.97 per workplace and £24.19 per participating employee. In comparison with car users [mean 7.3 minutes, standard deviation (SD) 7.6 minutes], walkers (mean 34.3 minutes, SD 18.6 minutes) and public transport users (mean 25.7 minutes, SD 14.0 minutes) accrued substantially higher levels of daily MVPA during the commute. Participants who walked for ≥ 10 minutes during their commute were more likely to have a shorter commute distance (p < 0.001). No access to a car (p < 0.001) and absence of free workplace car parking (p < 0.01) were independently related to walking to work and using public transport. Higher quality-of-life scores were observed for the intervention group in a repeated-measures analysis (mean 0.018, 95% CI 0.000 to 0.036; scores anchored at 0 indicated ‘no capability’ and scores anchored at 1 indicated ‘full capability’).

Conclusions
Although this research showed that walking to work and using public transport are important contributors to physical activity levels in a working population, the behavioural intervention was insufficient to change travel behaviour. Broader contextual factors, such as length of journey, commuting options and availability of car parking, may influence the effectiveness of behavioural interventions to change travel behaviour. Further analyses of statistical and qualitative data could focus on physical activity and travel mode and the wider determinants of workplace travel behaviour.

Trial registration
Current Controlled Trials ISRCTN15009100.

Funding
This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 7, No. 11. See the NIHR Journals Library website for further project information. Living Streets, a UK charity promoting everyday walking, provided funding for the intervention booklets and free pedometers for distribution to participants in the intervention group.