An assessment of physiotherapist's delivery of behaviour change techniques within the SOLAS feasibility trial.

Delivering the SOLAS intervention BCTs with high fidelity was not feasible. The assessment of partial delivery of BCTs provided greater insight into the techniques that should be removed from the protocol or that may require further training. Complex interventions should consider a list of 'core' or mandatory BCTs alongside 'optional' BCTs, depending on the target behaviour, and the needs of individual participants. Statement of contribution What is already known on this subject? BCTs are the smallest active components of behavioural interventions, yet typically their effectiveness is determined through meta-analyses. Attempted delivery of BCTs is often unaccounted for yet may provide valuable insight into difficulty with delivery. There is a need to investigate BCT implementation beyond simple presence/absence to identify protocol refinements or required BCT training. What does this study add? BCT delivery was assessed in greater depth than previous research, including partial delivery. Highlights the need for appropriate training in BCTs that are difficult to deliver, particularly those associated with 'goals and planning' Highlights the need for intervention-specific criteria as to what constitutes 'high', 'moderate', and 'low' fidelity.