Table 2.

Content of baseline measures from self-completed questionnaire

Concept	Measurement method	Details
Bodily pain	- self-completed manikin	"In the past 4 weeks have you had pain that has lasted for one day or longer in any part of your body?"
Complaint specific functioning	Western Ontario and McMaster Universities OA index (WOMAC LK3.0) [61]	pain (0–20), stiffness (0–8), physical function (0–68) subscales
Participant-nominated principal functional problem		"Because of your knee, what one thing gives you the most problems?" 11 point NRS
Knee pain intensity and unpleasantness		11 point NRS
Illness perceptions	Illness Perceptions Questionnaire Revised (IPQ(R)) [54]	9 dimensions: illness coherence, treatment control, personal control, timeline (acute/chronic), timeline (cyclical), consequences, emotional representation, identify, causes
Patient's self-efficacy	Arthritis Self-Efficacy Scale [62]	11 items on 10 point NRS
Experiences and preferences for treatment	- previous experience with exercise - preference for trial treatments - perceived helpfulness of trial treatments - outcome expectancy with trial treatments	yes, no 5 point Likert scale 4 point Likert scale 11 point NRS
Quality of life	EuroQol EQ-5D [63]	Summary score and 100 mm VAS score
Occupational characteristics	- current employment status - satisfaction with employment situation - current/recent job title - socio-economic classification - work loss in last 6 months due to knee problem	working full time, working part time, working in the home, unemployed/seeking employment, not working due to ill health/disability, student, retired very satisfied, satisfied, neither, unsatisfied, very unsatisfied SOC 2000 [64,65]
Demographic characteristics	- date of birth, gender - marital status	single, married, widowed, divorced, cohabiting, single
Anthropometric characteristics	-self-reported height -self-reported weight