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

To investigate physiotherapist's (PTs) fidelity to 31 protocol-listed behaviour change techniques (BCTs) during a group-based self-management intervention. This study also explored the PTs delivery of these BCTs beyond the present or absent dichotomy, using a third variable, partial delivery (i.e., attempted).

Assessment of the intervention arm of the Self-management of Osteoarthritis and Low back pain through Activity and Skills (SOLAS) cluster, randomized controlled feasibility trial, using quantitative methods.

Eight PTs delivered six SOLAS classes each, of which 50% were audio-recorded and transcribed. Transcripts were coded by two raters using the Behaviour Change Technique Taxonomy v1 and an intervention-specific manual and assessed for the delivery (i.e., full, partial, or absent) of the 31 BCTs and their target behaviours. Fidelity was calculated as fully delivered BCTs listed as a percentage of those due to take place within each class.

Physiotherapists delivered a mean 20.5 BCTs per class (68.3%; range = 64.9-72.4%). Of these, 17 BCTs were fully delivered in each class representing moderate fidelity to the protocol (56.8%; range = 53.5-59.3%). A further 3.5 BCTs per class (11.5%; range = 8.7-14.8%) were partially delivered. BCTs associated with 'goals and planning' were often poorly delivered.

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.