Darcy Ummels

Supplement file S3.1 Interview Guide Introduction:  Introduce yourself (name, function)  Explain you would like to record this interview with a memo recorder  Explain that everything the patients says will be used without their name  Ask if they agree with recording the interview  Ask if they have any question based on the information you just provided Question 1: Which activity tracker did you use? Question 2: Which information did you receive from your physiotherapist before using the activity tracker? Question 3: Can you briefly explain how you experienced the use of the activity tracker? Question 4: With witch purpose was the activity tracker used in your therapy? Sub question : Did you discussed the results in with your physiotherapist? Continue with: How did you discussed these results? OR How would you have liked to discuss these results? Sub question : How can an activity tracker be used in your therapy to improve the results of the therapy? Question 5: Would you purchase an activity tracker? In case the participants wants to buy an activity tracker: ‐ If you would buy an activity tracker, which information you would like to know beforehand? ‐ How would you want to compare this with other activity trackers? (for example wearing location, price and feasibility)