Body mass index vs deuterium dilution method for establishing childhood obesity prevalence, Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania.

OBJECTIVE: To compare the World Health Organization (WHO) body mass index (BMI)-for-age definition of obesity against measured body fatness in African children. METHODS: In a prospective multicentre study over 2013 to 2017, we recruited 1516 participants aged 8 to 11 years old from urban areas of eight countries (Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania). We measured height and weight and calculated BMI-for-age using WHO standards. We measured body fatness using the deuterium dilution method and defined excessive body fat percentage as > 25% in boys and > 30% in girls. We calculated the sensitivity and specificity of BMI z-score > +2.00 standard deviations (SD) and used receiver operating characteristic analysis and the Youden index to determine the optimal BMI z-score cut-off for classifying excessive fatness. FINDINGS: The prevalence of excessive fatness was over three times higher than BMI-for-age-defined obesity: 29.1% (95% CI: 26.8 to 31.4; 441 children) versus 8.8% (95% CI: 7.5 to 10.4; 134 children). The sensitivity of BMI z-score > +2.00 SD was low (29.7%, 95% CI: 25.5 to 34.2) and specificity was high (99.7%, 95% CI: 99.2 to 99.9). The receiver operating characteristic analysis found that a BMI z-score +0.58 SD would optimize sensitivity, and at this cut-off the area under the curve was 0.86, sensitivity 71.9% (95% CI: 67.4 to 76.0) and specificity 91.1% (95% CI: 89.2 to 92.7). CONCLUSION: While BMI remains a practical tool for obesity surveillance, it underestimates excessive fatness and this should be considered when planning future African responses to the childhood obesity pandemic.

The use of anthropometric measurements and the influence of demographic factors on the prediction of VO(2max) in a cohort of adolescents: the PAHL study.

BACKGROUND: [Formula: see text] prediction models have not focused on children and adolescents from South Africa and have not included various demographic factors as possible predictors. AIM: The purpose of this study was, therefore, to determine whether a valid [Formula: see text] prediction function can be developed from several anthropometric measurements and demographic factors of a cohort of adolescents in South Africa. SUBJECTS AND METHODS: A total of 214 adolescent boys (n = 88) and girls (n = 126) (15.82 ± 0.68 years) were selected. Demographic, sport and maturation data were collected by means of questionnaires, whereas anthropometric measurements were taken by accredited anthropometrists and the 20-m Shuttle Run Test (SRT) executed to determine indirect [Formula: see text] values. A forward stepwise multiple regression analysis was performed to identify the cluster analysis reduced [Formula: see text] predictors and a cross-validation was performed in order to validate the prediction function. RESULTS: Muscle mass percentage, sport participation level, stature, hip circumference and ectomorphy acted as significant predictors (p < 0.05) of the adolescents' indirect, 20-m SRT [Formula: see text] values. Seventy per cent of the variance in the indirect, 20-m SRT [Formula: see text] values could be explained by this model. Cross-validation also confirmed the model's validity. CONCLUSION: RESULTS indicate that the [Formula: see text] of adolescents from different racial backgrounds, living areas and gender groups can be accurately predicted by making use of a population-specific model.

Effects of the number of ball touches among elite youth players during small-sided soccer games.

BACKGROUND: This study investigates the effects of manipulating the number of ball touches (free play vs. two touches) on the physical and technical actions of elite male youth soccer players during 5v5 + 2 goalkeepers (GKs) small-sided games (SSGs). METHODS: Players played in two different SSGs: 1) free play, where the number of touches per possession was not restricted; and 2) two touches, where players were limited to a maximum of two touches per ball possession. A total of 24 male elite youth soccer players (age: 14.79±0.71 years; body mass: 56.02±1.41 kg; body height: 164±2.12 cm) participated in the study. Players' physical metric and technical performance data were captured using a global positioning system and video camera, respectively. A paired-samples t-test or Wilcoxon Signed-Rank Test was employed to examine differences in players' technical performance variables depending on SSGs' ball-touch rules. RESULTS: The results show significantly more unsuccessful passes (t=-3.48; P=0.04; d=1.92) when players were limited to two touches than when there were no pass limits. The physical metrics indicate that total distance covered (Z=-2.90; P=0.001; d=0.07), meters per minute (Z=-3.44; P=0.001; d=0.11), low-speed running (Z=-2.25; P=0.02; d=0.04) and high acceleration (Z=-1.90; P=0.05; d=0.28) were significantly higher when touches were unlimited than when they were not. CONCLUSIONS: Soccer coaches should decide the number of touches per ball possession they allow depending on their tactical and/or physical objectives in training.

Association between Physical Activity and Health Outcomes (High Body Fatness, High Blood Pressure) in Namibian Adolescents and Adult women.

Regular physical activity (PA) is known to promote the physical and mental health of children and adolescents and further prevent the development of health problems in adulthood. Information on body composition and PA is crucial for health promotion strategies and for epidemiological studies informing policies. However, there is limited data on the association between body composition and PA in Namibia. This dearth of published data is a significant shortcoming in the development of strategies and policies to promote PA in Namibia. Therefore, this cross-sectional study was conducted to determine the association between PA as a dependent variable and independent variables such as high blood pressure and body fatness as measured by different methods (gold standard deuterium dilution, body mass index, mid upper arm circumference, and waist circumference). The study included 206 healthy adolescent girls aged 13-19 years and 207 young adult females aged 20-40 years from Windhoek, Namibia. PA was measured using the PACE+ questionnaire in adolescents, and the GPAQ questionnaire was used for adults. In adolescents, only 33% of the participants met the recommended guidelines for PA, compared to only 2% for adults. Nevertheless, the study found no statistically significant association between PA and blood pressure indices (p-value < 0.05) among adolescents and adults. However, there was a significant association between PA and high body fatness (p-value < 0.001) and waist circumference (p-value = 0.014) in adolescents. Among adults, PA was significantly related to waist circumference only. In conclusion, failure to meet recommended PA guidelines is strongly associated with abdominal obesity and high body fatness. The knowledge gained from this study may be used by policymakers in the development of strategic policies and interventions aimed at promoting PA as a public priority and improving health outcomes.

Results From South Africa's 2022 Healthy Active Kids' Report Card on Physical Activity, Body Composition Proxies, and Nutritional Status in Children and Adolescents.

BACKGROUND: Physical activity (PA) and nutrition in children have an impact on overall physical and mental well-being, cognitive, and social development. This study aims to report on the best current available evidence on PA, body composition proxies, and nutritional status of South African children and adolescents, based on the published findings between 2018 and 2022, which comprise the 2022 Healthy Active Kids South Africa Report Card. METHODS: A comprehensive literature search of online databases, along with hand searching and a gray literature search, was conducted based on PA, body composition proxies, and nutrition indicators defined, in part, by the Active Healthy Kids Global Alliance. RESULTS: Compared with the 2018 report card, there was an improvement in the majority of PA indicators which include overall PA (B-), active transportation (B-), physical fitness (B-), and government policy and programs (C). Body composition proxies and most of the nutrition indicators remained unchanged. The indicators that regressed from 2018 to 2022 included community and environmental influences (D), as well as participation in organized sport (D-). CONCLUSIONS: Despite the apparent improvement in overall PA levels in children and adolescents, there is a lack of tangible evidence of actual implementation of policies and programs. There was also a lack of nationally representative data for most indicators. Overall, there is a need to identify intersectoral, equitable approaches for promoting PA and healthy eating in South African children and adolescents and ongoing monitoring and surveillance.

Development and validation of anthropometric predictive equations that estimate the total body water and fat-free mass in Tunisian adults.

OBJECTIVE: To develop and validate equations that estimate total body water (TBW) and fat-free mass (FFM) in adults using anthropometric measurements. METHODS: A cross-sectional study was conducted among 178 adults (77 men and 101 women; aged 18-59 years). Participants were distributed by sex and age groups, and then randomly assigned to equal two groups; the development (n = 89) and the validation (n = 89). The anthropometric measurements included height and weight. The deuterium dilution technique (DDT) estimated TBW and FFM. Linear regression models were used with the TBW and FFM as the dependent variable, and height and weight as the independent variables. Cross-validation was performed by Bland and Altman plot, and the new anthropometric equations were developed. RESULTS: In the validation sample, the developed equations had high R2 of 94.4 for both TBW and FFM in all age groups, and low standard errors (RMSE: 1.80 kg for TBW and 2.44 kg for FFM). The pure error was 2.03 for the TBW equation and 2.71 for the FFM equation. The Bland-Altman plot illustrated the good level of concordance between the TBW and FFM predicted by the new equations as determined by DDT. The following developed equations showed a better agreement with the DDT: [Formula: see text]; [Formula: see text]. CONCLUSION: In this study, we developed and validated prediction equations for the estimation of TBW and FFM from DDT in healthy adult Tunisian population. The newly anthropometric prediction equations seem to be the most accurate for Tunisian adult.

Results From South Africa's 2016 Report Card on Physical Activity for Children and Youth.

BACKGROUND: We present results of the 2016 Healthy Active Kids South Africa (HAKSA) Report Card on the current status of physical activity (PA) and nutrition in South African youth. The context in which we interpret the findings is that participation in PA is a fundamental human right, along with the right to "attainment of the highest standard of health." METHODS: The HAKSA 2016 Writing Group was comprised of 33 authorities in physical education, exercise science, nutrition, public health, and journalism. The search strategy was based on peer-reviewed manuscripts, dissertations, and 'gray' literature. The core PA indicators are Overall Physical Activity Level; Organized Sport Participation; Active and Outdoor Play; Active Transportation; Sedentary Behaviors; Family and Peer Influences; School; Community and the Built Environment; and National Government Policy, Strategies, and Investment. In addition, we reported on Physical Fitness and Motor Proficiency separately. We also reported on nutrition indicators including Overweight and Under-nutrition along with certain key behaviors such as Fruit and Vegetable Intake, and policies and programs including School Nutrition Programs and Tuck Shops. Data were extracted and grades assigned after consensus was reached. Grades were assigned to each indicator ranging from an A, succeeding with a large majority of children and youth (81% to 100%); B, succeeding with well over half of children and youth (61% to 80%); C, succeeding with about half of children and youth (41% to 60%); D, succeeding with less than half but some children and youth (21% to 40%); and F, succeeding with very few children and youth (0% to 20%); INC is inconclusive. RESULTS: Overall PA levels received a C grade, as we are succeeding with more than 50% of children meeting recommendations. Organized Sports Participation also received a C, and Government Policies remain promising, receiving a B. Screen time and sedentary behavior were a major concern. Under- and over-weight were highlighted and, as overweight is on the rise, received a D grade. CONCLUSIONS: In particular, issues of food security, obesogenic environments, and access to activity-supportive environments should guide social mobilization downstream and policy upstream. There is an urgent need for practice-based evidence based on evaluation of existing, scaled up interventions.