Eligible papers were retrieved using strategies employed in previous reviews. Overall, 16 relevant papers were identified, including four pilot studies and 12 full trials. Interventions were based on a variety of behavioural sciences theories. The most common setting for interventions was churches. Most interventions lasted >6 months; few interventions included >6 months of post-intervention follow-up. Overall, studies identified within-group differences showing positive improvements in PA, and most studies showed statistically significant between-group differences in at least one measure of PA. A quality score was used to rate various elements of the studies and provide a numerical assessment of each paper; scores ranged from 3 to 10 out of 13 possible points. The current review indicates a continued need for studies that use objective PA measures, assess long-term intervention impact, provide specific PA goals for interventions, include more attention to strategies that can increase retention and adherence among AA study participants, include AA men and determine the independent and synergistic effects of individual and environmental (socio-cultural and built) change strategies.

Purpose The purpose of this study was to determine whether the published left-wrist cut-points for the triaxial GENEA accelerometer, are accurate for predicting intensity categories during structured activity bouts. Methods A convenience sample of 130 adults wore a GENEA accelerometer on their left wrist while performing 14 different lifestyle activities. During each activity, oxygen consumption was continuously measured using the Oxycon mobile. Statistical analysis used Spearman's rank correlations to determine the relationship between measured and estimated intensity classifications. Cross tabulation tables were constructed to show under- or over-estimation of misclassified intensities. One-way chi-square tests were used to determine whether the intensity classification accuracy for each activity differed from 80%. Results For all activities the GENEA accelerometer-based physical activity monitor explained 41.1% of the variance in energy expenditure. The intensity classification accuracy was 69.8% for sedentary activities, 44.9% for light activities, 46.2% for moderate activities, and 77.7% for vigorous activities. The GENEA correctly classified intensity for 52.9% of observations when all activities were examined; this increased to 61.5% with stationary cycling removed. Conclusion A wrist-worn triaxial accelerometer has modest intensity classification accuracy across a broad range of activities, when using the cut-points of Esliger et al. Although the sensitivity and specificity are less than those reported by Esliger et al., they are generally in the same range as those reported for waist-worn, uniaxial accelerometer cut-points.

Race, PA, and exercise intensity are important factors in explaining differences in CRF. After accounting for demographics, PA, and VMET, a large proportion of the variance in CRF remains unexplained. Thus, other factors should also be considered when examining racial/ethnic differences in CRF.

Obesity is a known risk factor for cardiometabolic disease. Increasing aerobic capacity (VO2max) reduces adiposity, maintains weight, and reduces the risk of developing obesity and cardiometabolic disease. Two major determinants of aerobic capacity are the metabolic properties specific to a particular muscle fiber type and the capacity of the cardiorespiratory system to deliver nutrient-rich content to the muscle. Recent research suggests that some race/ethnic groups, particularly non-Hispanic Black subjects, are predisposed to a reduced VO2max by way of muscle fiber type. Combined with insufficient physical activity, these characteristics place non-Hispanic Black subjects at an increased risk for obesity and other adverse health outcomes when compared with other race/ethnic groups. The purpose of this review was to suggest a model for explaining how skeletal muscle fiber type may contribute to reduced aerobic capacity and obesity among non-Hispanic Black subjects. Our review indicates that metabolic properties of type II skeletal muscle (e.g. reduced oxidative capacity, capillary density) are related to various cardiometabolic diseases. Based on the review, non-Hispanic Black subjects appear to have a lower maximal aerobic capacity and a greater percentage of type II skeletal muscle fibers. Combined with reduced energy expenditure and reduced hemoglobin concentration, non-Hispanic Black subjects may be inherently predisposed to a reduced maximal aerobic capacity compared with non-Hispanic White subjects, thereby increasing the risk for obesity and related metabolic diseases.

SummaryThis review assessed the effectiveness of pre-school-and school-based obesity prevention and/or treatment interventions targeting healthy eating, physical activity or obesity in African American children and adolescents. Systematic searches were conducted for English-printed research articles published between January 1980 and March 2013. Retained articles included experimental studies conducted in the United States that targeted ≥80% African American/black children and adolescents and/or studies whose results were stratified by race/ethnicity, and that were conducted in pre-schools/head start or schools (excluding after-school programmes). Of the 12,270 articles identified, 17 met the inclusion criteria (preschool, n = 2; elementary school, n = 7; middle and secondary schools, n = 8). Thirteen studies found significant improvements in nutrition (pre-school, n = 1; elementary, n = 7; secondary, n = 5) and three found significant improvements in physical activity (pre-school, n = 1; elementary, n = 2) variables of interest. Two studies (pre-school, n = 1; secondary, n = 1) reported significant reductions in obesity in African American children. The evidence available suggests schoolbased interventions are effective in promoting healthy nutrition behaviours in African American children. Conclusions overall and, particularly, about effects on physical activity and obesity are limited due to the small number of studies, differences in assessment approaches and a lack of follow-up assessments.