Table 1.

Overview of the intervention components, the behaviour change strategies and the targeted constructs

Intervention component	Dose	Description	Behaviour change strategy	Targeted construct
Structured group exercise	60 min 2/week	Participants could choose to attend one of five different exercise facilities in Oslo. The different exercise groups were led by an exercise physiologist. The exercise training programme was designed as a low-threshold activity. The sessions had the following structure: a 15 min warm-up with easy and fun games, 40 min of floor ball and/or football plus some strength exercises and a 5 min cool down. Seven participants did not attend any of the sessions (one trained by himself and six were not motivated) and two were injured at the first exercise session. The mean attendance was 60 % (range: 11–100 %)	Provide opportunities for PA Increase social support for PA Promote mastery learning through skill training Improve knowledge and skill to perform PA Promote positive outcomes Provide credible role models Social modelling	Environment Behavioural capability Expectancies Self-control Self-efficacy
Group lectures	2 × 2 h	Major topics: What is PA? PA and health link; short- and long-term effects The harms of physical inactivity PA recommendations and how to achieve these Activity examples Setting small goals Identifying and reducing perceived barriers Making a PA plan Seeking social support Self-reward Both attendees and non-attendees received written summaries of the lecturers	Improve knowledge of PA options, including non-vigorous PA Improve knowledge of how to incorporate PA into a daily routine Enhance PA expectancies Improve goal setting Improve problem solving of PA barriers Improve social support for PA	Behavioural capability Expectancies Self-control Self-efficacy
Individual counselling sessions	1 × 1 h	All participants completed this part of the intervention. The counselling was based on the concept that all advice must match the participants’ experiences of PA and their degree of motivation. Together with the participant, the primary goal was to find activities that could be implemented in a normal week, with the sum of these activities enabling them to reach the PA recommendations. After discussing activity options, the participants set the goals they wanted to achieve over the 5-month period. Finally, we discussed barriers by asking “What do you think can stop you from carrying out this activity plan?”, and the possible barriers, and solutions to them were discussed and written down	Identify opportunities for PA Improve knowledge and skill to perform PA Enhance goal setting Enhance problem solving Promote mastery Identify and problem solve barriers to PA	Environment Behavioural capability Self-control Self-efficacy
Phone call	1 × 5–15 min	3–5 weeks before the post-test, intervention participants were telephoned. The focus of this conversation was to discuss the activity plan, to make changes if necessary, and to encourage further efforts. All participants were reached within three attempts	Provide feedback on PA behaviour Reinforce problem solving Provide encouragement and help	Social support Self-control Self-efficacy