Over the last decade, physical activity has become a key outcome domain in the assessment of rheumatic and musculoskeletal diseases (RMDs). Physical activity can be defined as any bodily movement produced by skeletal muscle that results in energy expenditure. Both physical and mental aspects of health in RMDs have been associated with optimal levels and patterns of physical activity. Also, intervention studies promoting physical activity in people with RMDs have largely confirmed these health benefits. Although there is consensus on its importance, the assessment of physical activity is complex and research in this area is rapidly growing. This lecture will therefore give a narrative overview of the state-of-the-art assessment of physical activity in RMDs considering the perspective of a researcher, a clinician, a patient and (to a lesser extent) the general population.
In a first part, this lecture will discuss the relationship between physical activity and energy expenditure. More specifically, we will explain how total energy expenditure can be partitioned in obligatory energy expenditure to support basal metabolism (basal/resting metabolic rate), diet-induced energy expenditure and activity-induced energy expenditure (physical activity). A quick overview of gold standard tools to assess each component will be discussed in non-technical way. We will focus on the assessment of activity-induced energy expenditure (physical activity) using patient-reported (e-)questionnaires and (e-)diaries, observer-based and technology-based outcomes in RMDs. Often used single-sensor devices e.g. pedometer but also trends in more complex-sensor devices e.g. wearables combined with apps will be discussed.
In a second part, we will shortly present the OMERACT framework to evaluate the measurement properties (i.e. how good is it?) of physical activity assessment tools. We will present the latest findings in this area for people with RMDs. Reliability and validity of commonly used outcomes e.g. steps, physical activity level or bouts of moderate to vigorous activities in RMDs and beyond will be presented.
In a last part, we will formulate guiding principles in selecting the right physical activity assessment tool for your clinical or research question taking into account cost, measurement properties and feasibility (usability) for both clinicians and patients.
Disclosure of Interest None declared