Fig. 1

Summary of volunteer recruitment to the CT with each recruitment method (a) and the advantages and disadvantages of each recruitment method (b). Recruitment methods have been ranked as; most effective (green), moderately effective (amber), least effective (red), based on the number of volunteers recruited to the CT. % represents the proportion of responding volunteers. BMI body mass index, DTP declined to take part, NHS National Health Service, NR no response, NSAIDS nonsteroidal anti-inflammatory drugs, PA physical activity, PMH past medical history