Lee Smith is an epidemiologist in the Faculty of Science and Engineering at the School of Psychology and Sport Science, Anglia Ruskin University, UK, with expertise in physical activity and sedentary behaviour. Lee researches ways in which we can increase levels of physical activity and reduce sedentary behaviour across the lifespan and within special populations. Mark A. Tully is Research Director of the School of Medicine and Professor of Public Health at Ulster University, UK. Prof Tully’s research focuses on addressing population levels of physical inactivity and sedentary behaviour, which are major causes of poor physical and mental wellbeing. His research includes interventions targeting older adults and socioeconomically disadvantaged communities. In addition, he is interested in the effects of changes in the built environment on behaviours.