Table 3 Content per motivational lesson

In this lesson, students become aware of their own physical activity behaviour. Based on the anonymous physical activity group mean, students can compare and evaluate their own physical activity behaviour

Students are asked to give a grade to their own physical activity behaviour (1–10). After this, they are asked why they did not score 2 points lower. The idea here is that students come up with things they are doing.

The students discuss all advantages and disadvantages of physical activity and inactivity to create ambivalence.

Students are made aware of the current physical activity norms (at 60 min of physical activity per day) and sedentary guidelines (less than 2 h of sedentary behaviour per day).

Different athletes are compared by means of Youtube videos. During this lesson, students are made aware that different physical activities require different qualities (e.g. a 100 kg judoka is not a good 100 m distance runner and vice versa).

See also Additional file 2. this is a table/exercise adapted from the book ‘Bewegen, Sport en Maatschappij’ (physical activity, sports and society) [8] by Boon, Pecht, Rijper & Stegeman.

First the students are asked how confident they are to start or commence a physical activity. In the action plan the student describes the what, when, where, and how (what can they do themselves, who do they need, where can they find help) of their physical activity plan.

Students write a short essay about what they want to do, what they want to achieve, and why.

Students discuss how they will try to achieve their goals, and help each other when necessary.

Repetition of lesson 1. In this lesson, the students also have to come up with an idea of what physical activity behaviour they want to start in the coming 2 months.

Students are reminded of lesson 12 and their action plan

Students discuss (perceived) barriers and solutions to overcome these barriers.

If-then statements are made to help students to overcome (perceived) barriers.