Take a Stand!-a multi-component intervention aimed at reducing sitting time among office workers-a cluster randomized trial.

Background: Prolonged sitting time has been associated with adverse health outcomes. Interventions at work may contribute to reduced sitting. The objective was to test if a multicomponent work-based intervention can reduce sitting time and the number of prolonged sitting periods (> 30 min), increase the number of sit-to-stand transitions and decrease waist circumference and body fat percentage among office workers. Primary outcomes were: change in sitting time, prolonged sitting periods and sit-to-stand transitions at follow-up 1 month later. Methods: At four workplaces, 19 offices (317 workers in total) were cluster randomized for intervention or control. The intervention included the appointment of local ambassadors, management support, environmental changes, a lecture and a workshop. Sitting time was measured using an ActiGraph GT3X+ fixed on the thigh. Data were processed using Acti4 software providing data on time spent sitting, standing and doing other activities. Control participants were instructed to behave as usual. Follow-up measurements were obtained after 1 and 3 months. Results: At 1 and 3 months, total sitting time was 71 ( P < 0.001) and 48 min ( P < 0.001) lower per 8-h workday in the intervention group compared with the control group. At 1 month, the number of prolonged sitting periods was lower (-0.79/8-h workday, P < 0.001) and sit-to-stand transitions were higher (+14%/sitting hour, P = 0.001) in the intervention compared with the control group. After 3 months, trends persisted. The body fat percentage was lower by 0.61 percentage points ( P = 0.011) in the intervention group compared with the control group after 3 months. Conclusions: The multicomponent workplace-based intervention was effective in reducing sitting time, prolonged sitting periods and body fat percentage, and in increasing the number of sit-to-stand transitions.

Intra-individual variability in day-to-day and month-to-month measurements of physical activity and sedentary behaviour at work and in leisure-time among Danish adults.

BACKGROUND: Accelerometers can obtain precise measurements of movements during the day. However, the individual activity pattern varies from day-to-day and there is limited evidence on measurement days needed to obtain sufficient reliability. The aim of this study was to examine variability in accelerometer derived data on sedentary behaviour and physical activity at work and in leisure-time during week days among Danish office employees. METHODS: We included control participants (n = 135) from the Take a Stand! Intervention; a cluster randomized controlled trial conducted in 19 offices. Sitting time and physical activity were measured using an ActiGraph GT3X+ fixed on the thigh and data were processed using Acti4 software. Variability was examined for sitting time, standing time, steps and time spent in moderate-to-vigorous physical activity (MVPA) per day by multilevel mixed linear regression modelling. RESULTS: Results of this study showed that the number of days needed to obtain a reliability of 80% when measuring sitting time was 4.7 days for work and 5.5 days for leisure time. For physical activity at work, 4.0 days and 4.2 days were required to measure steps and MVPA, respectively. During leisure time, more monitoring time was needed to reliably estimate physical activity (6.8 days for steps and 5.8 days for MVPA). CONCLUSIONS: The number of measurement days needed to reliably estimate activity patterns was greater for leisure time than for work time. The domain specific variability is of great importance to researchers and health promotion workers planning to use objective measures of sedentary behaviour and physical activity. TRIAL REGISTRATION: Clinical trials NCT01996176 .