Table A1.

Interview guides.

Subgroup	Interview Questions
Teachers	Initial Question
	Do you include some form of physical activity during your lessons? If so, what are your experiences? If not, can you say why not?
	Core Questions
	1. What do you think of the idea of introducing additional physical activity at school to improve cognitive performance and academic performance? 2a. What possibilities do you see in general for additional physical activity at school? 2b. If so, with what goal would you introduce additional physical activity? Does it make any difference to you whether this is introduced to improve health or to improve cognitive skills or academic performance? 3. What possibilities can you see for introducing physical activity during or in between your lessons in the classroom? 4. What, in your opinion, is the best way to provide additional physical activity at school? 5. What, in your opinion, is required to make a success of introducing additional physical activity in the school setting? And what is required to make this a permanent component of the curriculum? 6. What, in your opinion, are the most important points to consider when implementing additional physical activity in the school setting?
Principals	Initial Question
	What is the vision and policy of the school with respect to physical activity? In what way is attention focused on physical activity in the school curriculum? Is some form of physical activity implemented by the teachers in their lessons?
	Core Questions
	1. What do you think of the idea of introducing additional physical activity at school to improve cognitive performance and academic performance? 2a. In your opinion, what possibilities are there for introducing additional physical activity in the school curriculum? 2b. If so, with what goal would you introduce additional physical activity? Does it make any difference to you whether this is introduced to improve health or to improve cognitive skills or academic performance? 3. In your opinion, what is the best way to embed additional physical activity in the school curriculum? How do you envisage this in practice? 4. In your opinion, who is the most suitable person to provide additional periods of physical activity? 5. What, in your opinion, is required to make a success of introducing additional physical activity in the school setting? And what is required to make this a permanent component of the curriculum? 6. What, in your opinion, are the most important points to consider when implementing additional physical activity in the school setting?