Table 4 Summary of the results and conclusions, and suggestions for (clinical) research

Definition of mobility

● Generally includes the terms movement and ability to move but varies on conditions.

Strong agreement:

● A clear and standardised definition of mobility is useful to me.

● Mobility is broadly defined as the ability to move oneself.

● Mobility includes the use of assistive devices (e.g. wheelchair).

Moderate agreement:

● Mobility includes the context of travel/commuting.

Low agreement:

● Mobility is clearly defined.

● Mobility in standardized settings (e.g. lab or clinical environment) requires a different definition than mobility in a daily life environment.

● No uniform definition.

● Generally includes the terms movement and ability to move.

● Variability between definitions regarding the conditions.

● Define mobility as the ability to move, with or without the use of assistive devices.

● Specify conditions if any applied, i.e. the form of movement (e.g. walking, exercising, travel/ commuting), the role of the environment (e.g. ideal conditions, daily life).

Conceptual framework

● Conceptual frameworks differ in how they conceptualise mobility and the included components.

● A third of respondents used a conceptual framework to assess mobility; the ICF was most often used.

Strong agreement:

● A clear conceptual framework defining constructs and measures is required to determine mobility.

● Mobility related constructs can be aligned with individual ICF components within the components of body functions and structures, activities and participation, environmental factors, and personal factors.

Moderate agreement:

● A conceptual framework is useful to me.

● To define mobility, ICF offers a useful basic conceptual framework for research.

Low agreement:

● For health professionals, the WHO ICF is a suitable framework to determine mobility.

● For researchers, the WHO ICF is a suitable framework to determine mobility.

● Multiple conceptual frameworks are available in the literature with variability in how mobility is conceptualised.

● There is a need for a clear conceptual framework for mobility.

● There were conflicting opinions between both questionnaires on the suitability of the ICF as a framework to determine mobility.

● No recommendations can be made on a conceptual framework to determine the physical domain of mobility

● Use of the ICF framework to classify constructs in the components ‘body functions and structures’ and ‘activity and participation’, reflecting capacity and performance.

Constructs

● Ninety-two unique constructs of mobility were reported.

● Median scores of the relevance of multiple constructs were similar (varied between 6 and 9].

● Only ambulation, gait function, (instrumental) activities of daily living and physical activity were identified as moderately relevant

● None of the other constructs was identified as very or moderately relevant.

● Mobility encompasses multiple constructs.

● Variability in the classification and identification of constructs.

● Define if physical capacity and/or physical performance was assessed and how it was measured.

Strong agreement:

● Mobility is determined by multiple constructs requiring different measurements.

● Classification of muscle function under body functions and structures.

● Physical capacity and physical performance are different constructs with different definitions.

● Classification under capacity or performance depends on how it is measured.

● Physical capacity is defined by measurements under standardized/ideal conditions and represents the ‘can do,‘ i.e. what a person is maximally capable of.

● Physical capacity and physical performance are different constructs.

● The ‘can do’ and ‘do’ (i.e. what a person can do and what a person actually does in their daily life) are separate constructs of mobility.

● Capacity is representing the ‘can do,‘ i.e. what a person is maximally capable of.

● Performance is defined by measurements embedded within a (daily) task/activity.

● The term physical performance is often used instead of physical capacity; this terminology should be used appropriately to avoid confusion.

● The term function means the same as the term capacity.

● Muscle function is an umbrella term for muscle strength, muscle power and muscle endurance.

Moderate agreement:

● An overview of constructs of mobility is useful to me.

● Classification of muscle quality under body functions and structures.

● Physical performance is defined by what a person actually does in his or her environment.

● A construct should be classified under capacity or performance within the ICF depending on how it is measured.

● Capacity is defined by measurements under standardized/ideal conditions.

● Performance is representing the ‘do’ i.e. what a person actually does in their daily life.

● The terms function and functioning have different definitions.

Low agreement:

● Constructs and measurements to determine mobility are well-defined.

● Physical activity is an important construct of mobility.

● Muscle status is an important construct of mobility.

● Terminology of capacity and performance is used interchangeably.

● The term function is not defined and depends on what type of function is referred to (e.g. physical function, muscle function)

● The terms function and functioning differ in their definitions.

● Physical performance is defined by measurements embedded within a (daily) task/activity and represents the ‘do’ i.e. what a person actually does in their daily life.

● Define the terms function and functioning in terms of body functions, capacity or performance in relation to the type and environment of function(ing) assessed.

● Classification of all other constructs.

● Physical capacity is defined by what an individual can do in a standardised environment.

● The term function refers to body functions.

● Physical function is an umbrella term for lower extremity function, upper extremity function, back and neck function, and (instrumental) activities of daily living.

● Muscle function can also be termed muscle capacity.

● Muscle function can also be termed muscle quality.

● Constructs within the physical domain of mobility need to be further identified, defined and classified.

Measures

● Eighty-nine unique measures of mobility were reported.

Strong agreement:

● A core-set of mobility measures is useful to me.

● Potential data sharing or use of other one’s data for mobility related research is useful to me.

Moderate agreement:

● A core-set of mobility measures should be used for mobility both as a determinant or outcome.

Low agreement:

● Determining mobility requires a standardised core-set of measures.

● Mobility should be measured differently dependent on whether mobility is considered a determinant or outcome.

● Mobility is measured using multiple measures.

● A core-set of mobility is useful for researchers and/or clinicians, also in order to potentially share data in a standardised way.

● A core-set of measures should include the measure and the format of assessment to subsequently link them to the appropriate constructs.