Adults that increase their physical activity can improve their health, and reduce future risks to health, but long−term changes are difficult to sustain. This study assesses whether it is worth providing further support, 3 months after giving initial advice, to those who have managed to do more physical activity. All participants will initially be given an interactive DVD. A researcher from Sheffield Hallam University will provide two telephone follow ups at one month intervals to assess physical activity levels. Only those that have increased their physical activity at this point will remain in the study. These participants will receive a "mini booster", a "full booster" or no booster. The "mini booster" consists of a two telephone calls one month apart to discuss physical activity and usage of the DVD. A "full booster" consists of a face−to−face meeting with the facilitator at the same intervals. The purpose of these booster sessions is to help the individual to maintain their increase in physical activity. The investigators will measure the differences in physical activity, quality of life and costs, associated with the booster interventions, 3 months and 9 months from randomisation. The research will be carried out in 20 of the most deprived neighbourhoods in Sheffield. These locations have large, ethnically diverse populations, high levels of economic deprivation, low levels of physical activity, poorer health and shorter life expectancy. Participants will be recruited through general practices and community groups, as well as by postal invitation to ensure the participation of minority ethnic groups and those with lower levels of literacy. Sheffield City Council and Primary Care Trust fund a range of facilities and activities to promote physical activity and variations in access to these between neighbourhoods will make it possible to examine whether the effectiveness of the intervention is modified by access to community facilities.