Participants were: aged 40-64 years; resident in deprived areas of Sheffield, UK; and, had recently
become physically active as a result of using a brief intervention following an invitation from a mass mailout.
Interventions: Motivational Interviewing ‘boosters’ aimed at sustaining change in physical activity status delivered
face-to-face or over the telephone compared with no further intervention. Outcomes of the feasibility study:
recruitment of 60 participants from mailout of 3,300; retention of 45 participants with 3-month follow-up
accelerometry measurements; 70% of those randomised to boosters receiving intervention per protocol. Sample
size and power were recalculated using the accelerometry data collected