Background: Accelerometers provide an objective assessment of physical activity and are frequently deployed for at least multiple days. However, it is unclear how to summarize multiple days into one overall physical activity estimate, particularly in the presence of missing data. This study compared summarization method prediction and precision, and the ...
Hip bone mineral density (BMD) is an important biomarker of fracture risk, but as a standalone measure it lacks information on modifiable causal factors. The relationship between hip BMD and physical activity (PA)-based skeletal loading estimates could provide a biomarker for prescribing PA changes in high risk patients. Ten ...
We will present the results of analysis of physical activity data collected with accelerometers on 10000+ subjects in National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the US population. The data have been analyzed with recently developed multilevel functional data analysis approaches that focus on modeling variability ...
Objectives: To examine the validity and reliability of the Fitbit Flex against direct observation for measuring steps in the laboratory and against the Actigraph for step counts in free-living conditions and for moderate-to-vigorous physical activity (MVPA) and activity energy expenditure (AEE) overall. Methods: Twenty-five adults (12 females, 13 males) wore a Fitbit ...
Objective: Household factors (electronic media equipment, play equipment, physical activity in the home, and social support) have been associated with childhood moderate- to vigorous-intensity physical activity (MVPA), but little is known about how these factors differ across diverse countries. The objective was to explore household correlates of objective MVPA in ...
Background: Activity trackers are increasingly popular with both consumers and researchers for monitoring activity and for promoting positive behavior change. However, there is a lack of research investigating the performance of these devices in free-living contexts, for which findings are likely to vary from studies conducted in well-controlled laboratory settings. ...
Abstract: It has been hypothesised that an ‘activitystat’ may biologically regulate energy expenditure or physical activity levels, thereby limiting the effectiveness of physical activity interventions. Using a randomised controlled trial design, the aim of this study was to investigate the effect of a six-week exercise stimulus on energy expenditure and ...
Background: This study examined the associations of objectively measured physical activity in Physical Education and recess with academic performance in youth. Methods: This cross-sectional study was conducted with 1,780 participants aged 6 to 18 years (863 girls). Physical activity was objectively measured by accelerometry and was also classified according to sex- and age specific ...
Introduction: Accelerometers are commonly used to assess physical activity. Consumer activity trackers have become increasingly popular today, such as the Fitbit. This study aimed to compare the average number of steps per day using the wrist-worn Fitbit Flex and waist-worn ActiGraph (wGT3X-BT) in free-living conditions. Methods: 104 adult participants (n = 35 ...
Background: Use of mass transit has been proposed as a way to incorporate regular physical activity into daily life because transit use typically requires additional travel to access and depart the stop or station. If this additional travel is active, a small but potentially important amount of physical activity can ...