A theory-driven, web-based, computer-tailored advice to influence sitting at work was developed. The study investigated the effects of this computer-tailored intervention to influence workplace sitting on behavioural measures.

The study investigated the effects of the theory-driven, web-based, computer-tailored intervention to influence workplace sitting on objectively measured sitting time, standing time and breaks from sitting, as well as self-reported context-specific sitting. The computer-tailored advice was compared to a generic advice and a 'no-advice' control at 1-month and 3-months follow-up. The 'tailored' group received a web-based computer-tailored intervention including personalized feedback and tips on how to reduce and/or interrupt workplace sitting. The 'generic' group received a web-based intervention containing generic information and tips to reduce and/or interrupt workplace sitting. The control group was a waitlist control condition and received the generic intervention after completing all measurements. Participants were recruited from a convenience sample of two companies (university and environmental agency) in Flanders (i.e. northern Dutch-speaking part of Belgium), mainly employing desk-based workers, having more than 100 staff members and each having at least three different worksite locations.

Inclusion Criteria:

• being employed

Exclusion Criteria:

• not being able to stand