JMIR Publications

ABSTRACT

Background:

An increasing number of multi-component workplace interventions are being developed to reduce sedentary time and promote physical activity among office workers. The Physical Activity at Work trial was one of these interventions, but it yielded an inconclusive effect on sedentary time after six months with a low uptake on the movement breaks, the main intervention component. The present study investigates the factors contributing to the trial's outcome.

Objective:

The study evaluates the recruitment and context, implementation, and impact mechanisms of the Physical Activity at Work study.

Methods:

Following the Medical Research Council guideline for process evaluation of complex interventions, this mixed-methods study aims to evaluate the PAW study’s recruitment and context (how job nature and recruitment of each cluster affected the movement break participation), implementation (dose and fidelity), and mechanisms of impact (how intervention components affected movement break participations, and the facilitators and barriers of the movement breaks). Data from accelerometers, pedometers, questionnaires, on-site monitoring, and focus group discussions were used for the evaluation. Linear mixed models were employed to analyse the effects of different intervention components on the movement breaks. Subsequently, qualitative analysis of the focus group discussion provided additional insights into the relationship between intervention components.

Results:

The trial implementation was satisfactory regarding dose delivery and fidelity. However, the limited uptake of the movement breaks could be attributed to 1) context-related challenges, including jobs requiring high cognitive engagement or frequent out-of-office work and meetings; 2) the absence of goal-setting aspects in the detailed design of individual and social components; 3) the lack of effective and sustainable supporting components at the environmental and organisational levels; and 4) elevated workloads in specific clusters, exacerbated during peak periods of the COVID-19 pandemic, serving as a significant barrier. On the other hand, automatic motivation, such as feeling active and relaxed, was ranked as the top facilitator to join movement breaks, followed by reflective motivation of perceived health benefits.

Conclusions:

All intervention components significantly contribute to the trial outcome. Our process evaluation encompasses multiple aspects to explain the trial's findings. However, to validate all trial assumptions in future studies, the intervention's logic model must be thoroughly reconstructed and finalised. Clinical Trial: The PAW study was registered at the Thai Clinical Trials Registry (ID TCTR20200604007) on 02 June 2020.