Movement and Behaviours Measurement Study

Knowledge on health implications of sedentary time and physical activity has been substantially improved in the last decades with accelerometer-based estimations. The popularity of these devices is partially explained by the capacity of objectively recording physical behaviors (e.g., sleep, sedentary time, physical activity…) during the whole day. The so-called "cut-point" approach is behind most of the research on physical activity with accelerometers. Cut-points provide metrics that are easy to understand, to translate to the public and to replicate by researchers in different settings. Usually, the minimum requirement is to use cut-points adapted to the age-group of the population of interest.

Under this paradigm, cut-points have been developed in all age-groups and with a variate set to data collection and processing protocols. However, some scenarios lack of available cut-points to implement, being older adults (> 65 years) the population with less alternatives of cut-points to use. In this sense, studies with older adults choose cut-points developed in younger adults to classify physical activity intensities. Biomechanical and physiological differences between adults and older adults advise against using this strategy. Therefore, relative energy expenditure and functional status should be considered for future cut-points design. Moreover, must be also awarded that hardly any previous cut-points validation protocols have been performed in a free-living setting. For this reason, more studies following these designs seems necessary to improve cut-points population's validity. Missing all mentioned factors could lead to physical activity and sedentary behavior patterns misclassification in this population.

Inclusion criteria

• 65 years and older
• Non-institutionalized
• Physical function assessment (SPPB>3)

Exclusion criteria

• Have started an exercise program.
• Mini-Mental Score < 18.
• Presenting any physical activity contraindication.