Table 1.

Recruitment of participants

Step	Selection criteria	Documented variables	Performed by
1.	Patients ≥ 70 years who have seen their GP within the past 6 months → N1	Number (N1)
2.	Screening N1: Exclusion of institutionalised patients (nursing home) → N2	Number (N2)
3.	Screening N2 for inclusion and exclusion criteria → N3	Number (N3)	Study physician and practice nurse
	if N3 is < 20 → Exclusion of practice
	if N3 is between 20 and x* → N3 = N4 → Step 4
	if N3 is > x* → x* patients are randomly selected → x* = N4 → Step 4
4.	Final list of patients to be invited → N4	-Number (N4) -Year of birth -Sex
5.	Mailing of invitations to N4 for a screening at the GP's practice; appointments with interested patients are made according to a given timetable.		Practice nurse
6.	Screening of patients at the GP's practice → N5 -final assessment of eligibility -patient information -written informed consent	-Number (N5) -Year of birth -Sex -Written informed consent -Reasons for exclusion	1. GP 2. Exercise therapist
7.	Patients who keep their first appointment with the exercise therapist to start the intervention → N6	-Number (N6) -All patient characteristics	Exercise therapist

* X is set to 70 for the first practice and may be adapted during the course of the study depending on the recruitment success of the following steps.