Subtheme	Study	Direct participant data	Author description of data
Influence of programme supervisors	Campbell 2001	"Well I felt because [physiotherapist] took the trouble of explaining it all to me I couldn't turn around and say, "well blow it, why bother sort of thing? you know?" And when I first turned round and said that I would do it, I felt well alright I wasn't obligated to do it but I felt let's do my bit towards it, you know. I didn't want her. p.134. ME: "So would you say that some weeks you do them [the exercises] two or three times?" Eileen: "Some weeks I can't…" ME: "Sometimes you can't make it at all?" Participant: "Yeah. Latterly. I think this is my own fault. I mean when I was going [to see the physiotherapist] every week you make yourself sort of do it don't you…I must admit I am not so good now I am not going." p.135. MT "Since you have stopped seeing [the physiotherapist] have you stopped doing the exercises?" Participant: "Yes I'm sorry I have yes. But as I said I haven't had no pain…I wondered whether it was temperature or dampness or something like that you see. Now there is nothing wrong with them." MT: "So you feel if there is nothing wrong with it you feel there is not much point in a…" Participant: "Well that's it. It's the wrong attitude I know."	The complex reciprocity that surrounds the relationship between therapist and patient and the obligation patients felt towards the physiotherapist, particularly the desire not to let her down, were important reasons for high levels of initial compliance. One participant explained how difficult it was to continue the exercises programme since she stopped seeing the physiotherapist. p.135.
	Hendry 2006	"The gym instructors advise you and give you confidence that you're not going to make things worse." p.562. "I think the physiotherapist or someone with a medical background is the best person to supervise exercise." p.562. "At the gym they give you one‐to‐one attention and an individual programme that's right for your body." "The supervision at the gym is very good; they monitor what you do." p.562. "…I had to stick rigidly to what he had said, the weights that he had specified…the idea was to stretch it that little bit further than I normally would do in order to support the joint more…but too much would…cause more damage and not enough wouldn't do any good…I was quite impressed actually by his knowledge…and I did exactly what he said and I did notice an improvement, a definite improvement." p.563.	The expert advice and supervision available in gyms or from physiotherapists was valued. p.563.
	Hinman 2016	"The most important thing is listening to the physio and doing the exercises because he motivated me to do the exercises." p.486	The impact of this feeling of accountability was to increase their motivation to exercise. People with knee OA described feeling accountable to their physical therapists and not wanting to let down the therapist. p.483.
	Hurley 2010	"…I think it's really a lot, in fact an enormous amount, to do with the facilitator, she's both kind of encouraging and yielding and nurturing and understanding, but also was able to use a bit of steel and get us off our bums, you know, so she's got those kind of qualities naturally…" p.7. "…[Physiotherapist] gave us enormous confidence because she is such a, she is very very confident, obviously highly qualified, so it was good to have some body for an hour giving you good advice, which was sound…" p.7.	The care, support and guidance participants received during the informal discussions helped build a trusting, collaborative partnership between patient and physiotherapist. This increased participant's confidence and trust in the physiotherapist and belief in the rehabilitation programme. The interpersonal qualities and professional skills of the supervising therapist were considered as important to the success of the programme as the content of the programme itself. p.7. However, their greatest concern was losing the ongoing support of the physiotherapist would undermine their motivation to exercise, and they expressed a desire for ongoing support. pp.8‐9.
	Larmer 2014b; Larmer 2014a	"She's so enthusiastic and she's pleased to see us every day, whether she feels like she is or not. She's always very welcoming and um yeah, very encouraging and you can ask her things all the time." p. 91.	The importance of good 'therapist/instructor' interaction was noted. The instructor helped create an enjoyable and supportive atmosphere, which appeared crucial for many participants. p.91.
	Moody 2012	"…umm the instructor we had was very, very good and ah I think it was just so good. And I think the motivation was there which is the big thing is to get you motivated you know?" p.66. "jolly you along." p.66. "Yes, I think the instructor was sort of aware of our capabilities and kept the challenge up. And it made it more interesting that way, because if you did the same thing over and over at the same level, it would be boring." p.66. "Yeah, so it's just funny little things that keep you thinking you have a responsibility to attend 'cause someone's gonna miss you." p.66. "No, I'd sooner have a leader." p.66.	The instructor was important and group members considered essential attributes of an instructor were: being understanding, tolerant, friendly and someone who will "jolly you along." The participants valued their relationship with a challenging instructor with whom they could establish a connection. It emerged that accountability was an important factor in motivation. Participants felt if they missed a class the instructor or group would notice, and this helped keep them motivated to go. The fact that there was a record of attendance being kept also contributed towards this. Participants were cognisant of the instructor watching them and noticing if they were doing exercises incorrectly, that he/she would playfully encourage them to challenge themselves and they wanted to do well for the instructor. All these factors contributed to the feeling of accountability, and were strong motivators to attend the classes. A number of questions as to how a water‐based exercise programme could continue to run, especially if funding for it was limited, were discussed. One question was the use of a 'buddy' system, where people would be paired up and go to the pool with their friend to do the exercises together. However, most participants were unenthusiastic about this idea as they would rather attend in a group with an instructor and did not want to rely on one person to go with. It was asked if groups could run with a short‐term instructor for a few weeks to demonstrate the exercises, with the groups then becoming self‐sufficient. Reactions to this idea were mixed. Some felt this would work, as long as it was a structured group with a set time and place to meet. However, most participants felt that an instructor was essential and that a class without an instructor would fall apart; that they were too forgetful to remember the exercises without an instructor there to tell them or that there would not be sufficient motivation. It was considered embarrassing to go without an instructor and some felt it would not be safe exercising without an instructor to guide them. A few participants had continued with the water exercises on their own since the classes had finished, and had found it difficult to maintain. Nominating a leader from the group to be the instructor was suggested and some participants liked this idea but other people felt this would not be fair on the nominated instructor. The instructor was important and group members.
	Petursdottir 2010	"I think that physical therapists are the best to help those who have a physical dilemma to start exercising…and start carefully, and under supervision. I think that is very important." p.1020. "Well, I always say that my physical therapist is as good as any psychologist." p.1021. "What keeps me going now is attending physical therapy sessions." p.1021.	The participants described the importance of suitable exercise and their experience of how exercise should progress gradually under the supervision of a qualified person. p.1020. All participants had some experience with physical therapists, most of it positive, and many participants placed emphasis on the fact that the encouragement and understanding they received from their physical therapists were very important. The importance of listening and good communication was highlighted and seemed to play a big role in the perceived benefits of physical therapy. p.1021. 4 participants exercised under the supervision of a physical therapist at the time of the interviews. These participants described how the physical therapists kept them going and that the therapists were sometimes the key to going on. p.1021.
	Thorstensson 2006	"It is something you notice when you give it up, since it [the exercise] was very difficult to do on your own…As there was nobody to supervise me it was easy to deteriorate again…Then there was nobody to urge you on." "I think that [an instructor] is good because then you learn what to do so that you do not do it in the wrong way. Otherwise you might do certain movements incorrectly and put too much pressure on your knees." p.55.	To receive guidance: this conception concerned the perceived need for moral support, encouragement and instructions on how to exercise. The statements were about compliance and the anxiety of doing something wrong.
	Larmer 2014b; Larmer 2014a	"The physiotherapist determined the gradual increase of the exercises; he told me, for example, to increase the exercises by five minutes. I liked it that he told me what to do, nevertheless, he was my physiotherapist." p.275. The approach of the physiotherapist was very democratic, which I appreciated. Together, we discussed the activities and the increase of the activities. I could indicate to what extent I wanted to increase the activities, to what extent I could maintain the exercises. p.276.	Some participants reported that they were actively involved in choosing the activities, in gradually increasing these activities, and in using the performance charts. In contrast, other participants reported that the main decisions were taken by the physiotherapist and that they performed the activities as instructed by the physiotherapist. It appeared that all adherent participants reported that they were actively involved in the whole process and that the physiotherapists had a coaching role during intervention. However, most non‐adherent participants reported that the physiotherapist made all decisions (which was sometimes a deliberate choice of the participants). Therefore, it seems that active involvement of the participant facilitates adherence to exercises and activities. p.275.