Process evaluation for the STAMINA randomised controlled trial: A protocol - Saïd Ibeggazene; Sophie Reale; Alison Scope; Grace Price; Eileen Sutton; Liam Bourke; Michelle Collinson; Jamie Stokes; Liz Steed; Derek Rosario; Amanda J. Farrin; Steph J.C. Taylor (PLoS ONE, 2025)