Physical inactivity is one of the most prevalent major health risk factors, with 8 in 10 US adults not meeting aerobic and muscle-strengthening guidelines, and is associated with a high burden of cardiovascular disease. Improving and maintaining recommended levels of physical activity leads to reductions in metabolic, hemodynamic, functional, body composition, and epigenetic risk factors for noncommunicable chronic diseases. Physical activity also has a significant role, in many cases comparable or superior to drug interventions, in the prevention and management of >40 conditions such as diabetes mellitus, cancer, cardiovascular disease, obesity, depression, Alzheimer disease, and arthritis. Whereas most of the modifiable cardiovascular disease risk factors included in the American Heart Association's My Life Check - Life's Simple 7 are evaluated routinely in clinical practice (glucose and lipid profiles, blood pressure, obesity, and smoking), physical activity is typically not assessed. The purpose of this statement is to provide a comprehensive review of the evidence on the feasibility, validity, and effectiveness of assessing and promoting physical activity in healthcare settings for adult patients. It also adds concrete recommendations for healthcare systems, clinical and community care providers, fitness professionals, the technology industry, and other stakeholders in order to catalyze increased adoption of physical activity assessment and promotion in healthcare settings and to contribute to meeting the American Heart Association's 2020 Impact Goals.

The impact of a new national kidney allocation system (KAS) on access to the national deceased-donor waiting list (waitlisting) and racial/ethnic disparities in waitlisting among US end-stage renal disease (ESRD) patients is unknown. We examined waitlisting pre- and post-KAS among incident (N = 1 253 100) and prevalent (N = 1 556 954) ESRD patients from the United States Renal Data System database (2005-2015) using multivariable time-dependent Cox and interrupted time-series models. The adjusted waitlisting rate among incident patients was 9% lower post-KAS (hazard ratio [HR]: 0.91; 95% confidence interval [CI], 0.90-0.93), although preemptive waitlisting increased from 30.2% to 35.1% (P < .0001). The waitlisting decrease is largely due to a decline in inactively waitlisted patients. Pre-KAS, blacks had a 19% lower waitlisting rate vs whites (HR: 0.81; 95% CI, 0.80-0.82); following KAS, disparity declined to 12% (HR: 0.88; 95% CI, 0.85-0.90). In adjusted time-series analyses of prevalent patients, waitlisting rates declined by 3.45/10 000 per month post-KAS (P < .001), resulting in ≈146 fewer waitlisting events/month. Shorter dialysis vintage was associated with greater decreases in waitlisting post-KAS (P < .001). Racial disparity reduction was due in part to a steeper decline in inactive waitlisting among minorities and a greater proportion of actively waitlisted minority patients. Waitlisting and racial disparity in waitlisting declined post-KAS; however, disparity remains.

The problem of limiting equilibrium of a slope in a state of plane strain is formulated in terms of the variational calculus. Formulated that way, the analysis is carried out without any a priori assumptions with respect to the shape of the slip surface, or the normal stress distribution along it. Thus, on the basis of only a formal definition of the concepts of limiting equilibrium, and factor of safety with respect to strength, it is proven that the minimal factor of safety must occur on slip surfaces with a special geometrical property. This geometrical property ensures that the resultant of the infinitesimal normal and frictional forces either pass through a common point or are parallel to a common direction. It is shown that as a result of this geometrical property the minimal factor of safety is independent of the normal stress distribution along the critical slip surface. In the homogeneous and isotropic case the analysis shows that the critical slip surface may be either a log-spiral or a straight line. In a layered profile the critical slip surface may consist of series of log-spirals that have a common pole or a series of straight lines. In some cases the boundary between layers may be part of the critical slip surface. All the results obtained are valid for a general non-homogeneous, non-isotropic soil with arbitrary distribution of pore water pressure and external loads. Le problème plan de l'équilibre limite d'un talus est formulé dans le cadre du calcul des variations. L'analyse est faite sans aucune hypothèse à priori concernant la forme de la ligne de glissement ou la répartition des contraintes normales, le long de cette ligne. On montre que la valeur la plus faible du coefficient de sécurité est obtenue pour une ligne de glissement à géométrie particulière. La démonstration de ce résultat ne font appel qu'aux équations d'équilibre limite et à la définition du coefficient de sécurité unique, égal au rapport des caractéristiques réelles et réduites du matériau. Cette propriété géométrique particulière se distingue par le fait que les forces infinitésimales résultantes des contraintes normales et tangentielles le long de la ligne de glissement passent par un même point ou sont parallèles. Il en résulte que la valuer la plus faible du coefficient de sécurité est indépendente de la répartition des contraintes normales à la ligne de glissement critique. Dans le cas d'un milieu homogène et isotrope l'analyse montre que la ligne de glissement critique peut être soit une spirale logarithmique soit une ligne droite. Dans le cas d'un profil multicouches, la ligne de glissement critique peut comprendre soit une série de spirales logarithmiques à foyer commun soit une série de lignes droites, ainsi que l'interface entre les couches dans certains cas. Tous les résultats obtenus sont valables dans le cas d'un sol non homogène et non isotrope avec répartition quelconque de la pression intertitielle et des forces extérieures.

PurposeIn addition to excess adiposity, low cardiorespiratory fitness (CRF) and low musculoskeletal fitness (MSF) are important independent risk factors for future cardio-metabolic disease in adolescents, yet global fitness surveillance in adolescents is poor. The objective of this study was to describe and investigate geographical variation in levels of health-related physical fitness, including CRF, MSF, body mass index (BMI), and waist circumference (WC) in Chilean 8th graders.MethodsThis cross-sectional study was based on a population-based, representative sample of 19,929 8th graders (median age = 14 years) in the 2011 National Physical Education Survey from Chile. CRF was assessed with the 20-meter shuttle run test, MSF with standing broad jump, and body composition with BMI and WC. Data were classified according to health-related standards. Prevalence of levels of health-related physical fitness was mapped for each of the four variables, and geographical variation was explored at the country level by region and in the Santiago Metropolitan Area by municipality.ResultsGirls had significantly higher prevalence of unhealthy CRF, MSF, and BMI than boys (p<0.05). Overall, 26% of boys and 55% of girls had unhealthy CRF, 29% of boys and 35% of girls had unhealthy MSF, 29% of boys and 44% of girls had unhealthy BMI, and 31% of adolescents had unhealthy WC. High prevalence of unhealthy fitness levels concentrates in the northern and middle regions of the country and in the North and Southwest sectors for the Santiago Metropolitan Area.ConclusionPrevalence of unhealthy CRF, MSF, and BMI is relatively high among Chilean 8th graders, especially in girls, when compared with global estimates. Identification of geographical regions and municipalities with high prevalence of unhealthy physical fitness presents opportunity for targeted intervention.

An analytical framework for predicting the ground pressure distribution and tractive performance of tracked vehicles is presented. It takes into account all major design parameters of the vehicle as well as the pressure-sinkage and shearing characteristics and the response to repetitive loading of the terrain. The subsequent substantiation of the analytical method by means of full-scale tests made with an instrumented vehicle is described. A comparison between the theoretical prediction and test results is made and it is found that there is a fairly close agreement between them. This paper includes three sections: (i) an analytical method for predicting the normal pressure distribution; (ii) an analytical method for predicting the shear stress distribution and tractive performance; (iii) experimental substantiation of the analytical framework by means of full-scale tests. The analyticalframework presented is suitable for evaluating the effects of vehicle design parameters and terrain conditions on the performance of tracked vehicles with relatively short track pitch designed for high speed operation and for comparing the tractive performance of different tracked vehicle designs.angle of shearing resistance b,, 4, contact angles of the roadwheel with the track on the left-and right-hand side, respectively w angular speed