2014/01/01 by Boris A. Brühmann, Brühmann, Boris A., Martina E. Schmidt +3
Medicine · #Physical Activity and Health
paper · doi:10.3205/mibe000155
Background: The rapid development in technology promotes the increasing use of electronic activity monitors to assess physical activity in large-scale epidemiological studies. Our aim was to explore and discuss both subjective and objective methods assessing physical activity. Methods: Based on a thorough literature search, major strengths and limitations of questionnaires and electronic activity monitors in assessing physical activity are elaborated and discussed, taking into consideration physical activity in all its complexity. Important research questions and the aim and scope of physical activity assessment for next-generation research are defined. Results: Questionnaires can provide details and background information of physical activity, including type of activity, and can identify the activity behaviour patterns that underlie measurable endpoints such as energy expenditure, cardiorespiratory fitness, muscular strength, or certain biomarkers. They can differentiate well between settings and enable retrospective assessment. Electronic activity monitors, on the other hand, are rapidly becoming better at assessing energy expenditure and are good at quantifying the amount and intensity of physical activity and sedentary behaviour. Both methods, however, also have their weaknesses. While questionnaires may not be accurate, due to recall bias or incomplete assessment of all activity domains, electronic activity monitors are not able to provide information about setting, exact type and mode of activity, and cannot recognize and reliably assess resistance exercise or activities with or without carrying weights. Conclusions: Since physical activity is multidimensional and complex, no single method is suitable to capture all aspects and domains. Both methods have their strengths and limitations and do not compete with each other, but should be seen as complementary tools that assess distinct aspects of physical activity. Studies should therefore rely on both methods to enable improved public health recommendations for this complex lifestyle factor.