Table 1

Considerations for a future definitive trial

Objectives	Criteria for success
To evaluate the feasibility of procedures for a cluster randomised controlled trial in the public physiotherapy sector in Thailand (ie, randomisation, recruitment, data collection, adherence, trial management and follow-up).	Feasible to conduct a phase III trial No major obstruction issue and/or serious adverse event (assessed by trial monitoring). Feasible for the type of study (randomised design) (assessed by trial monitoring). Feasible for procedures of data collection, trial management and follow-up (assessed by trial monitoring). At least three participants a month per hospital.
To explore the acceptability of the ABPI among Thai physiotherapists and patients with acute non-specific neck pain.	The ABPI can be acceptable to Thai physiotherapists and patients with acute non-specific neck pain (explored by qualitative study). Acceptable rate ≥60% of participants in each group.
To estimate sample size in order to conduct an adequately powered definitive trial.	All parameters can be provided to calculate sample size for an adequately powered definitive trial.