Table 3 Key themes from the transcripts identifying interviewees’ reasoning behind their decision not to participate in the trial

Themes

Trial design and delivery

Physical-environmental:

• Climate/seasonal factors “It’s a bit off-putting I think really, as it’s very wet and gets dark early -you don’t want to be walking in it”

• GP practice venue was generally supported “At the practice, it’s easier, don’t change that” “I walk down there anyway when I go and see the doctor”

• Use of trial equipment specifically the accelerometer was not supported due to discomfort “It would put me off a bit because I’m waiting to have a heart monitor - I can’t cope with two” and inadequate recording “The monitor only indicates steps and I have problems with my feet so I ride a bike and that doesn’t record so well on the monitor”

Focus on walking:

• The trial’s focus on walking emerged as a preferred physical activity of older people and was favoured over other forms of physical activity “Walking is fine. It’s probably the best thing you can do at our age”

Socio-cultural influences:

• Individual versus group consultation was generally preferred “I’m not very good in groups I would say. I think I would prefer one-to-one”

• Social support was deemed important from peers, spouse or family “I discussed it (the trial) with my children and they said it was a good idea”

Altruistic factors:

• Older people are supportive of medical research and would like to help if they could “I would like to think of a way to help them in any way, research or whatever”

Current health and activity

Personal competence:

• Many believed they were already doing enough physical activity “I don’t really think it was a necessary thing for me to do because I think I do a lot of exercise anyway

• Real and perceived medical problems and fear of such problems were significant barriers to regular physical activity “I think that was one of my main worries, that I just felt my knee would get worse”

• For some, psychological barriers such as lack of confidence and depression posed significant challenges to participation “I suffer a lot of pain all the time, 24 hours a day, and it gets me depressed”

Practical reasoning

Time-related factors:

• Some devoted a lot of time to other commitments: work, caring for one’s family, recreation “I’m just really rather busy, I play a lot of sport and look after various people and I just don’t feel I would have the time to fit it all in”

• The main 3 month involvement in the trial was thought to be too long “I think 3 months is a bit of a long time”

Behavioural attributes:

• Changing behaviour appeared problematic due to existing routines "I've got into a routine I like to stay in. If I go and do anything different, it sounds silly, but I get a bit uptight"

• Many believed they did not need help and could increase physical activity on their own “Exercise is in my own hands if I choose to do something about it as opposed to being part of an organised team to do it”

• Lack of interest in physical activity: reluctance to do activities that are not enjoyed “I don’t want to spend every minute I’ve got free thinking I’ve got to do exercise”

• Acknowledgement of ‘slowing down’ in retirement "I find an awful lot of people our age, they think about exercise but very few do anything about it. As they get older, they slow down and can’t be bothered”