Despite the well-known benefits of physical activity, less than half of adults aged 55-75 years participate in sufficient physical activity. Short bouts of vigorous intermittent lifestyle physical activity (VILPA) accumulated throughout the day can contribute toward the recommended volume of physical activity. A rich characterization of the barriers and facilitators to participation in VILPA is needed to develop targeted interventions. This scoping review aimed to identify barriers and facilitators to participation in different components of VILPA in adults aged 55-75 years, and to map barriers and facilitators to the Theoretical Domains Framework. Within the 18 eligible studies, the most prevalent barriers were related to a person\'s skills, environmental context, and social influences. Most facilitators were related to a person\'s goals, social influences, and environmental context. Interventions to promote VILPA should test the effectiveness of behavioral change measures related to the unique barriers and facilitators in this age group.

Background. Increasing evidence suggests that vigorous physical activity (VPA) in youth may yield greater health benefits than moderate (MPA) or moderate-to-vigorous physical activity (MVPA). The purpose of this review was to assess the relationship between PA intensity and body composition, cardiorespiratory fitness (CRF), and cardiometabolic (CM) biomarkers in youth. Methods. We conducted a systematic review of observational studies examining PA intensity and selected health outcomes in youth aged 6 to 18 years. Forty-five articles were selected for final review. Results. VPA was more strongly associated with reduced body fat and central adiposity compared with MPA and/or MVPA. Additionally, VPA was more strongly associated with increased CRF when compared with lower intensities. Findings were inconclusive between all PA intensity levels and CM biomarkers, and several significant relationships observed for VPA were attenuated when controlling for CRF. Conclusions. A potential VPA dose is identified as yielding favorable health benefits in adiposity and fitness. While CM biomarkers were not consistently associated with PA intensity level, the literature suggests VPA may yield health benefits above those received from MPA for reduced adiposity and improved CRF. This review highlights the need for longitudinal observational and experimental studies to determine optimal VPA dose for CM health in youth.

BACKGROUND: Accelerometers are widely used to measure sedentary time, physical activity, physical activity energy expenditure (PAEE), and sleep-related behaviors, with the ActiGraph being the most frequently used brand by researchers. However, data collection and processing criteria have evolved in a myriad of ways out of the need to answer unique research questions; as a result there is no consensus.
OBJECTIVE: The purpose of this review was to: (1) compile and classify existing studies assessing sedentary time, physical activity, energy expenditure, or sleep using the ActiGraph GT3X/+ through data collection and processing criteria to improve data comparability and (2) review data collection and processing criteria when using GT3X/+ and provide age-specific practical considerations based on the validation/calibration studies identified.
METHODS: Two independent researchers conducted the search in PubMed and Web of Science. We included all original studies in which the GT3X/+ was used in laboratory, controlled, or free-living conditions published from 1 January 2010 to the 31 December 2015.
RESULTS: The present systematic review provides key information about the following data collection and processing criteria: placement, sampling frequency, filter, epoch length, non-wear-time, what constitutes a valid day and a valid week, cut-points for sedentary time and physical activity intensity classification, and algorithms to estimate PAEE and sleep-related behaviors. The information is organized by age group, since criteria are usually age-specific.
CONCLUSIONS: This review will help researchers and practitioners to make better decisions before (i.e., device placement and sampling frequency) and after (i.e., data processing criteria) data collection using the GT3X/+ accelerometer, in order to obtain more valid and comparable data.
UNASSIGNED: CRD42016039991.