Adherence and fidelity
The intervention was delivered largely as intended, and participants engaged well despite the disruption caused by the covid-19 pandemic. Participants in the intervention group took part in a median of 31 therapy sessions (interquartile range 22-40). The mean length of sessions was 71 minutes (standard deviation (SD) 30; range 5-220). Two thirds of sessions were delivered face-to-face (1357 (68%)). Fidelity of therapy delivery was 70% against PrAISED core principles rated from video recordings. In total, 4040/4863 (83%) of the expected calendars were returned. The intervention group participants reported completing a mean of 482 minutes of PrAISED exercise per month (SD 705; range 0-5310; 121 minutes/week). Of control group participants, 95 (54%) had one therapy session, 48 (27%) had two sessions, 29 (16%) had three sessions, 4 (2%) had four sessions, and one had five sessions.