Table 1.

Theoretical framework of acceptability themes and interpretation

Theme	Interpretation
Affective attitude	How an individual feels about the PBT. How do you feel about the training? What made you feel this way?
Self-efficacy	The participant’s confidence in their ability to perform the PBT. How did you do in the training?
Perceived effectiveness	The extent to which the participant perceives the PBT to potentially and actually (observed) be effective. To what extent did you experience effects from the training?
Ethicality	The extent to which the intervention had good fit with an individual’s value system and expectations of a falls prevention intervention. To what extent did the training fit with your views on falls prevention?
Intervention coherence	The extent to which the participant understands the aim of PBT and how it works. In your own words, what was the aim of the training?
Burden	The perceived amount of effort that was required to participate in the PBT. To what extent did you find the training strenuous? To what extent did you find the training challenging?
Opportunity costs	The extent to which benefits, profits or values were given up to participate in the PBT. To what extent did you forego other opportunities to participate in the training?

PBT, perturbation-based balance training.