Table 2.

Representative quotes from one-to-one interviews.

	People with CLBP	Peer support volunteers
Topic 1: expectations	“Hoping I could get more encouragement of what I should be doing” [P52, Male]	“Gone part time and I was looking for things to fill up my day. Also because I had experienced a pain – knees and hips, maybe I could learn from other people or maybe I could help them. Thought it was something good to be involved in” [PSV47, Female]
	“Thought meeting someone with similar problems would help accept how you were yourself and maybe offer suggestions” [P70, Female]
Topic 2: the intervention	Matching
	“[volunteer] was a lot younger than me but it didn’t matter, we both had active lives, we had a lot to relate to” [P56, Male]	“You don’t have to have a lot of other things in common if you both have back pain, both have an understanding” [PSV66, Male]
	Delivery
	“Both [face-to-face & telephone] were good…just as easy over the phone…but it’s vital to see a face, you couldn’t do them all by phone” [P52, Male]	“You could do it on phone but I need to see a person. I like meeting up. If the patient's at their home and on the phone they can't get things off their chest.” [PSV42, Female]
	“A week apart would be too fast, no time to put anything into practice…I also think an hour is long enough, it’s long enough for most people’s concentration spans.” [P70, Female]	“Body language is important. The physical thing too of getting out, it's an activity that gets you out and moving. So it could be negative just sitting at home doing Skype and e-mail, it's supposed to be active [back pain self-management].” [PSV66, Male]
	“[six sessions were] enough, felt it was time to finish, I was accomplishing what I could get out of it” [P52, Male]
	What I got out of it
	“It forced me to have an action plan…I’m doing exercises now and they are really helping” [P48, Male]	“Think I got as much out of it as the patients have. I learned a lot about pain and different people's pain thresholds, ways of managing. Think I’m more tolerant of back pain as a result of the study”. [PSV40,Female]
	“It gave me a wee push…although I am much the same I think about it more [back pain and self-management strategies] [P57, Female]	“ I learned some new things − pacing was good”. [PSV47, Female]
	‘Just somebody listening to you, getting a few things off your chest’ [P67, Female]
	“Don’t underestimate the importance of psychological support…sympathetic, encouraging, that was the biggest benefit…encouraged me to keep going with what I do already…encouraged me to not get too overwhelmed” [P70, Female]
	The intervention manual
	“Useful − I made a point of looking at it before & after session. Without the plan of action we would have wandered a lot” [P48, Male]	“The best thing I found was the manual it gave criteria to work to. If the patient went off on a tangent I could bring it back to focus using the manual and topic for that session…but the content could be halved” [PSV66, Male]
	“ A lot of the paperwork was repetitive…it’s not necessary to repeat. The matching meeting at the start explained it well…you need a note of how you felt it went each time, a certain amount of recording but not repetitive questions…we did look at some of the leaflets together…the Mental Health booklet was interesting…and not filled with little drawings, much more factual. [P70, Female]	“The resources were good but quite laborious for the patient, especially if they didn't like using computers…Pacing was good and dealing with pain. I used the bit ‘what are you hoping to achieve’ tried to go by that. We did end up speaking about other things but used it as a guide.” [PSV47, Female]
	‘Writing the activity diary was useful, it showed how I did too much, I could see where I should be relaxing more.’ [P67, Female]
Topic 3: study processes	Support
	“Good support from the study team.” [P68, Female]	“The support was very helpful. Phone-calls after the sessions were helpful.” [PSV66, Male]