A web-based intervention to promote physical activity in adolescents and young adults with cystic fibrosis: protocol for a randomized controlled trial oleh Narelle S. Cox, Beverley Eldridge, Sarah Rawlings, Julianna Dreger, Jennifer Corda, Jennifer Hauser, Brenda M. Button, Jennifer Bishop, Amanda Nichols, Anna Middleton, Nathan Ward, Tiffany Dwyer, Owen W. Tomlinson, Sarah Denford, Alan R. Barker, Craig A. Williams, Michael Kingsley, Paul O’Halloran, Anne E. Holland, On behalf of Youth Activity Unlimited – A Strategic Research Centre of the UK Cystic Fibrosis Trust