John Ronald Sirard

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CONTEXT Without detailed evidence of their effectiveness, pedometers have recently become popular as a tool for motivating physical activity. OBJECTIVE To evaluate the association of pedometer use with physical activity and health outcomes among outpatient adults. DATA SOURCES English-language articles from MEDLINE, EMBASE, Sport Discus, PsychINFO,(More)
PURPOSE In the present study, the authors extend previous cross-sectional findings by using a prospective design to determine whether physical and social environmental characteristics predict physical activity over 6 months. DESIGN Inactive adults were recruited to the Activity Counseling Trial, a multicenter, randomized, controlled trial of physical(More)
OBJECTIVE There is little epidemiologic research on longitudinal and secular trends in weight-related health behaviors throughout the stages of adolescence. In particular, few data are available to assess secular trends in various sedentary behaviors. The objective of this research was to investigate longitudinal and secular trends in physical activity and(More)
BACKGROUND This study aimed to evaluate the associations of selected demographic, individual, social, and environmental factors with moderate-to-vigorous physical activity (MVPA) in a sample of children and adolescents. METHODS MVPA was assessed among youth (n = 294) 10-17-years-old using the ActiGraph accelerometer. Youth completed measures of(More)
BACKGROUND Little is known about how the home environmental supports physical activity and screen media usage. The purpose of this study was to develop and test the reliability and validity of a self-report instrument to comprehensively reflect the availability and accessibility of physical activity and screen media equipment in the home environment. (More)
Active commuting to school (e.g. walking or bicycling) has been suggested as a strategy to increase children's physical activity 1, 2 and a number of walk-to-school websites now exist. 3–5 Several observational studies have found positive associations between walking to school and physical activity 6–9 but they are unable to determine the causal direction.(More)
BACKGROUND Little is known about the actual physical activity and screen time behaviors of an adolescent's friends relative to the individual's behavior. PURPOSE To determine the associations between an adolescent's physical activity and screen time and his/her nominated friends' physical activity and screen time. METHODS Data were obtained from EAT(More)
BACKGROUND Previous research on the environment and physical activity has mostly focused on macro-scale environments, such as the neighborhood environment. There has been a paucity of research on the role of micro-scale and proximal environments, such as that of the home which may be particularly relevant for younger adolescents who have more limited(More)
BACKGROUND To examine how factors from a social ecologic model predict physical activity (PA) among adolescents using a longitudinal analysis. METHODS Participants in this longitudinal study were adolescents (ages 10-16 at baseline) and one parent enrolled in the Transdisciplinary Research on Energetics and Cancer-Identifying Determinants of Eating and(More)
This study used latent class analysis to classify adolescent home neighborhoods (n=344) according to built environment characteristics, and tested how adolescent physical activity, sedentary behavior, and screen time differ by neighborhood type/class. Four distinct neighborhood classes emerged: (1) low-density retail/transit, low walkability index (WI),(More)