Early exercise in blunt chest wall trauma: protocol for a mixed-methods, multicentre, parallel randomised controlled trial (ELECT2 trial) oleh Ceri Battle, Alan Watkins, Kate Jones, Deborah Fitzsimmons, Fiona Elizabeth Lecky, Timothy Driscoll, Hayley Anne Hutchings, Susan Davies, Phillip A Evans, Shaun Harris, Claire O'Neill, Hannah Toghill, Sara Davies, Amy Charnock, Thomas Dawson, Joanne Prosser