Table 3.

Criteria for feasibility of the pilot randomised controlled trial

	Explanation	Operationalisation and unit
Study design
Recruitment rate	Relation between interested persons, eligible persons and study participants	n study participants / n interested persons [%]; n study participants / n eligible persons [%]
Recruitment period	Time expenditure for recruitment of study participants	Time [weeks]
Randomisation	Comparability of the randomised groups	Differences in primary outcomes between intervention- and control group at the beginning of the study [p-value]
Blinding	Practicability and success rate of the blinding of the assessor	Proportion of the participants, who inadvertently reveal their group assignment to the assessor [%]
Dropout rate	Drop-outs	n study participants who have not completed the study according to the protocol/ n study participants [%]
Assessments
Safety	Occurrence of adverse events/ complications	Absolute n of participants who had adverse events or showed aggravated symptoms related to the assessments
Duration	Duration of the test battery including the questionnaires in minutes	Time [min]
Acceptance	Participation in assessments and questionnaires	n of declined assessments or questionnaires/ n study participants [%]
Interpretability/Completeness	Occurrence of floor and ceiling effects	≥ 15% of study participants cannot perform an assessment; ≥ 15% of the study participants have the highest or lowest value of the scale
	Missing values in questionnaires or assessments	n missing values / n Items [%]. Critical if the median of missing items in a questionnaire or assessment is ≥10%.
Intervention
Extent of the treatment	Frequency	sessions per week per study participant
	Duration	Median duration of one session [min]
Feasibility of the exercises	Refusal rate and estimation of the feasibility by the therapist	n exercises refused/ n exercises offered [%]; structured rating of the feasibility by the therapist
Acceptance of the intervention	Subjective estimation of the study participants	Standardised personal rating by the participants
Adverse events	Adverse events or complications, e.g. pain, loss of function, and consultation of a physician	Overall n of adverse events (mild/moderate/severe) which are not, unlikely, possibly, probably or definitely related to the intervention
Costs
Staff	Training: investigation of the outcomes	Total Duration [min]; cost [€]
	Training: execution of the intervention	Total Duration [min]; cost [€]
	Screening and examination of the inclusion and exclusion criteria	Total Duration [min]; cost [€]
	Investigation of the outcomes	Total Duration [min]; cost [€]
	Execution of the intervention	Total Duration [min]; cost [€]
	Additional contact to the study staff initiated by the participants (questions and wishes)	Total Duration [min]; cost [€]
Structure	Measurement instruments (material costs, license costs, software for the analysis)	Cost [€]
	Equipment for the exercises	Cost [€]
	Ethics proposal	Cost [€]
	Registration of the study	Cost [€]
	Recruitment material (Flyer)	Cost [€]