Moderators in a physical activity intervention for adolescent girls.

BACKGROUND: The purpose was to explore whether baseline sociodemographic and physical characteristics moderated effects of an intervention on moderate-to-vigorous physical activity (MVPA), percent body fat, body mass index z-score, and cardiorespiratory fitness (CRF) at post intervention, relative to the control condition. METHODS: A secondary analysis of data from a group randomized trial including 24 schools (12 intervention and 12 control; N = 1519 girls) was conducted. Age, ethnicity, race, socioeconomic status, and pubertal stage were assessed via survey. Height, weight, MVPA (min/h), percent body fat, and CRF were measured. Mixed-effects linear models were performed. RESULTS: Compared to the control, the intervention increased overweight and obese girls' CRF (b = 0.28, p = 0.049; b = 0.31, p < 0.01, respectively), but not healthy weight girls' CRF (b = 0.04, p = 0.706). Pre- to mid-puberty girls in the intervention group had slightly lower post-intervention MVPA than those in the control (3.04 vs. 3.31, p = 0.055), while late to post-puberty intervention and control girls' post-intervention MVPA was similar (3.12 vs. 3.04, p = 0.542). CONCLUSIONS: A PA intervention can improve overweight and obese girls' CRF, possibly attenuating their cardiovascular risk. Effective strategies are needed to assist adolescent girls, especially those in pre- to mid-puberty, in maintaining their MVPA after an intervention ends. IMPACT: Moderators of physical activity intervention effects among adolescent girls are important to identify because the effectiveness of these interventions to date in this population has been limited. This article contributes to the notable gap in knowledge regarding moderators in physical activity interventions involving adolescent girls, particularly baseline characteristics that may moderate their responses to physical activity interventions. Awareness of the moderators can be useful for determining the type of intervention that may be successful in subgroups of adolescent girls and for tailoring a physical activity intervention to optimally meet each girl's needs to achieve maximal effects. Findings show that weight status moderated the intervention effects on cardiorespiratory fitness. Compared to the control condition, the intervention increased overweight and obese, but not healthy weight, girls' cardiorespiratory fitness. A physical activity intervention can improve overweight and obese girls' cardiorespiratory fitness, possibly attenuating their cardiovascular risk. Therefore, it is essential to include overweight and obese girls in PA interventions to help them reap this important benefit.

Mediators of Physical Activity Behavior Change in the "Girls on the Move" Intervention.

BACKGROUND: The minimal effect of interventions to date on increasing young adolescent girls' physical activity (PA) may be due to inadequate understanding of the mechanisms underlying behavior change, yet sparse research testing a PA intervention has examined the capacity of theories to explain PA, particularly when using objective measures. OBJECTIVES: The aim of the study was to examine whether constructs from the health promotion model and self-determination theory mediated changes in moderate-to-vigorous physical activity (MVPA) following a 17-week intervention. METHODS: The study was a secondary analysis of data from a group randomized trial, including 12 intervention and 12 control schools in the Midwestern United States. Data were collected in 2012-2016. Girls (fifth- to eighth-grade, N = 1,519) completed surveys on perceived benefits and enjoyment of PA, PA self-efficacy, social support and motivation for PA, and barriers to PA and wore accelerometers. RESULTS: The final path model had a good fit: χ(4) = 2.48, p = .648; goodness-of-fit index = 1; comparative fit index = 1; root-mean-square error of approximation = 0; standardized root-mean-square residual = 0.01. For MVPA change from baseline to postintervention, enjoyment (B = 24.48, p < .001) and social support (B = 30.48, p < .001) had a positive direct effect, whereas the intervention had a positive indirect effect through enjoyment and social support (B = 9.13, p < .001). Enjoyment (B = -13.83, p < .001) and social support (B = -17.22, p < .001) had a negative indirect effect on MVPA change from postintervention to follow-up. DISCUSSION: Enjoyment of PA and social support for PA may be important mediators of PA in young adolescent girls and warrant consideration when designing interventions.

Interventions to Increase Physical Activity in Children Aged 2-5 Years: A Systematic Review.

Comprehensive evaluation of prior interventions designed to increase preschoolers' physical activity is lacking. This systematic review aimed to examine the effect of interventions on objectively measured physical activity in children aged 2-5 years. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. In May 2014, we searched PubMed, CINAHL, PsycINFO, ERIC, SPORTDiscus, Cochrane, and Embase. Two reviewers independently identified and appraised the studies. Twenty-four articles describing 23 independent studies and 20 unique interventions met inclusion criteria. Of the 8 interventions resulting in a significant effect in objectively measured physical activity, all were center-based and included a structured physical activity component, 6 included multiple components, 5 integrated theories or models, and 4 actively involved parents. Seven of the 8 were randomized controlled trials. Due to the heterogeneity of the study designs, physical activity measures, and interventions, drawing definitive conclusions was difficult. Although the overall intervention effect was less than optimal, the review indicated that theory-driven, multicomponent interventions including a structured physical activity component and targeting both parents and their children may be a promising approach for increasing preschoolers' physical activity and warrant continued investigation using rigorous designs to identify those that are most effective.

Optimal design and experimental research on the spiral groove wheel fertilizer apparatus.

As the "core" of fertilizer machinery, the fertilizer apparatus has a significant impact on the effect of fertilization operation. At present, the straight-grooves type external groove wheel fertilizer apparatus is widely used, which has the problem that the fertilizer flow fluctuates periodically and is not conducive to precision fertilization. Therefore a kind of the spiral groove wheel fertilizer apparatus is proposed in the paper, and the designed fertilizer apparatus is experimented and optimized by using Design-Expert Software 10 and a self-made fertilizer experiment bench. Taking the fertilization amount and the variation coefficient of fertilization amount as the experiment index, the interaction effects of the groove radius, spiral rising angle, groove wheel rotation speed, and fertilizer tongue inclination of the spiral groove wheel type fertilizer wheel on the fertilization performance are analyzed. The quadratic regression models of multiple factors of the fertilization amount and the variation coefficient of fertilization amount are established. Through optimization and experiment validation, the optimal combination of parameters is determined as follows: the groove radius is 13.5 mm, the spiral rising angle is 62°, the groove wheel rotation speed is 29.4 r/min, the fertilizer tongue inclination is 5°, the fertilization amount is 17.810 g and the variation coefficient of fertilization amount is 5.60%.

Design and parameter study of banana crown mechanical cutting device.

Banana mechanical crown cutting tool which is a critical component of banana crown cutting machine is designed and studied in this paper. Experiments were designed to optimize parameters of the cutting tool. Indexes are cut surface quality grade of banana crown, maximum cutting force and useful power consumption. For banana preservation, get high grade of cut surface quality is more significant than consume less energy. Results of experiments show that the optimum parameters are as follows: cutting speed is about 50-60 mm/s, number of cut sets are about 4-6, angle between thick cutter and axis of banana rachis is about 5°, width of thick cutter is about 8-14 mm, thickness of thick cutter is about 2-3 mm, edge angle of thick cutter is between 20° and 30°, width of thin cutter is about 10-14 mm and thickness of thin cutter is about 0.2-0.4mm. This study helps to make the completely mechanical postharvest treatments for banana postharvest treatments.

Motivational interviewing to reduce anthropometrics among children: A meta-analysis, moderation analysis and Grading of Recommendations Assessment, Development and Evaluation assessment.

BACKGROUND: Limited systematic reviews exist to evaluate the effects of motivational interviewing (MI) on children's anthropometric factors. OBJECTIVE: This review examined the effects of MI interventions for children and/or parents on children's anthropometric factors and included moderation analyses and Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, we searched Cochrane Library, PubMed, CINAHL, EMBASE, PsycINFO, Sociological Abstracts, SPORTDiscus, Education Resources Information Center, and Web of Science in December 2020. A two-step double screening approach was applied: (1) screening titles and abstracts, and (2) screening full-text articles obtained in step 1. At each step, discussion occurred until reaching consensus. The Cochrane risk-of-bias tool was used to evaluate risk of bias, and GRADE system was applied to assess overall quality of evidence. We performed meta-analyses using the Comprehensive Meta-Analysis software. RESULTS: A total of 2209 records were found, and 45 eligible articles were retained. MI interventions had a pooled effect of -0.15 on body mass index (BMI; 95% confidence interval [CI]: -0.24 to -0.06), -0.36 on waist circumference (WC; 95% CI: -0.71 to -0.01) and -0.22 on percent body fat (95% CI: -0.41 to -0.03). Child baseline weight status and percent low-income families were identified as significant intervention moderators. According to the GRADE assessment, the quality of evidence on BMI percentile, BMI z-score and percent body fat was moderate, while quality on BMI and WC was low. CONCLUSIONS: In conclusion, culturally appropriate clinic- or home-based MI interventions with adequate duration, dose and active parental involvement are promising in reducing anthropometrics among children.

Attending After-School Physical Activity Club 2 Days a Week Attenuated an Increase in Percentage Body Fat and a Decrease in Fitness Among Adolescent Girls at Risk for Obesity.

PURPOSE: To evaluate the effect of a 17-week intervention, including an after-school physical activity (PA) club 3 d/wk, on moderate-to-vigorous physical activity (MVPA), body mass index (BMI) z score, percentage body fat (%BF), and cardiorespiratory fitness (CRF) among fifth to eighth grade girls having a BMI z score ≥0, and explore whether intervention outcomes varied by club attendance (1 vs 2 vs 3 d/wk). DESIGN: Secondary analysis of data from a group randomized controlled trial (N = 1519, 10- to 15-year-old girls: n = 753 intervention; n = 766 control). SETTING: Twenty-four Midwestern US schools (n = 12 intervention; n = 12 control). SAMPLE: Subsample (n = 1194 girls) from trial's intervention (n = 593 girls) and control (n = 601 girls) groups having BMI z scores ≥0. MEASURES: Moderate-to-vigorous physical activity (min/h), BMI z score, %BF, and CRF (V˙O2max: mL/kg/min) were estimated at baseline and postintervention. ANALYSIS: Linear mixed-effect models. RESULTS: Intervention group gained less %BF (B = -0.35, P = .016), and their CRF decreased less (B = 0.22, P = .010) than the control. Marginally significant findings showed girls attending the club an average of 1 d/wk had greater increases in %BF (B = 0.33, P = .087) and MVPA (B = 0.20, P = .083) and a greater decrease in CRF (B = -0.20, P = .061) than girls attending 3 d/wk. No differences occurred between girls who attended 2 versus 3 d/wk for any outcomes. CONCLUSIONS: The intervention attenuated an increase in %BF and a decrease in CRF among girls at risk for obesity from baseline to postintervention. Offering the after-school PA club 2 d/wk may be adequate for achieving outcomes.

Lifestyle Interventions in Preschool Children: A Meta-analysis of Effectiveness.

CONTEXT: With healthy behaviors becoming established in the preschool years, intervening with preschool children to assist them in establishing a healthy lifestyle and maintaining a long-term healthy weight is critical. To optimize future intervention designs, this meta-analysis aimed to estimate the effects of lifestyle interventions on BMI among preschool children and explore potential intervention moderators. EVIDENCE ACQUISITION: In October 2015, a search of PubMed, CINAHL, EMBASE, PsycINFO, ERIC, and Cochrane library databases yielded 52 eligible articles with 42 randomized intervention-control comparisons (31 prevention and 11 treatment). In 2016, weighted standardized mean differences for BMI were calculated using random-effects models to estimate effect sizes. EVIDENCE SYNTHESIS: The effect sizes were -0.19 (95% CI=-0.28, -0.09) and -0.28 (95% CI=-0.48, -0.09) kg/m2 for prevention and treatment interventions, with sustained effect sizes of -0.21 (95% CI=-0.35, -0.08) and -0.23 (95% CI=-0.43, -0.04) kg/m2, respectively. Child mean age, percentage Hispanic, and parental intervention sessions were common significant moderators. School-based or prevention interventions with active parental involvement did not yield better outcomes. Interventions targeting parents with parenting skill training and behavioral change strategies, and children with general health and nutrition education, resulted in greater effects. CONCLUSIONS: Although publication bias limits the validity of the study findings, the meta-analysis results highlight the promising intervention approaches of parenting skill training and behavioral change strategies to target parents. However, for children, general health and nutrition education should be employed.

Effects of a High Protein Food Supplement on Physical Activity, Motor Performance and Health Related Quality of Life of HIV Infected Botswana Children on Anti-Retroviral Therapy (ART).

OBJECTIVE: Despite existing evidence about the benefits of nutrition, physical activity (PA) and sport to the overall health and wellbeing of children, knowledge gaps remain on this relationship in children living with chronic conditions like HIV/AIDS. Such knowledge should inform context specific programs that could enhance the quality of life of children. The purpose of this study was to examine the effects of integrating a nutrition intervention (culturally tailored food supplement) into antiretroviral therapy (ART) on psychosocial outcomes and physical activity among HIV-positive children in Botswana. METHOD: 201 HIV-positive children (6-15 years; M = 9.44, SD = 2.40) were recruited and randomly assigned (stratified by age and gender) to two groups. The intervention group (n = 97) received a high protein (bean-sorghum plus micronutrients) food supplement, while the control group (n = 104) received a sorghum plus micronutrients supplement. Participants were followed over 12 months. Anthropometric measures, PA, motor performance, and health related quality of life (HRQL) were collected at baseline, 6 and 12 months. RESULTS: Mixed repeated-measures ANOVA revealed a significant time effect of the food supplement on target variables except body fat percentage, speed, and school functioning. Time × treatment interaction was found for physical functioning, psychosocial functioning and total quality of life score. Scores on physical functioning and total of quality life in the intervention group significantly increased from baseline to 6 months compared with the control group (p = 0.015). CONCLUSION: A combination of ART and nutritional intervention had a positive effect on physical functioning and total quality of life of HIV-positive children in this study. There were also improvements to physical activity and motor performance tests over time. More research is needed on long term effects of nutrition and PA interventions on HRQL in children living with HIV.

Interventions to prevent and manage overweight or obesity in preschool children: A systematic review.

OBJECTIVES: The preschool period is a pivotal time for lifestyle interventions to begin the establishment of long-term physical activity and healthy eating habits. This systematic review sought to (a) examine the effects of prevention and management interventions on overweight/obesity among children aged 2-5 years, and (b) explore factors that may influence intervention effects. DESIGN: A systematic review of randomized controlled studies was conducted. DATA SOURCES: Six databases, including PubMed, CINAHL, EMBASE, PsycINFO, ERIC, and Cochrane library, were searched for relevant studies. REVIEW METHODS: Data were extracted and checked by two reviewers. Each study was appraised based on 4 quality indicators adapted from the Cochrane Handbook for Systematic Reviews of Interventions. A narrative summary technique was used to describe the review findings. RESULTS: Thirty-seven articles describing 32 randomized controlled trials and 29 unique interventions were retained. Eight of 23 prevention and 4 of 6 management interventions resulted in significant weight loss, with 3 prevention and 5 management interventions showing sustained effects over 6 to 24 months. Of the 12 efficacious interventions, 10 included physical activity and nutrition components, 9 actively involved parents, and only 4 were theory-based. Interactive education was the most common strategy used for parents in prevention interventions, compared to behavioral therapy techniques in management interventions. For children, interactive education and hands-on experiences involving physical activity and healthy eating were equally used. CONCLUSIONS: Management interventions showed greater effects in weight loss compared to prevention interventions. Future prevention interventions in preschool children should target both parents and children, and focus on physical activity and nutrition through interactive education and hands-on experiences, although intervention effects were less than optimal. Management interventions should focus on parents as the "agents of change" for physical activity and nutrition while integrating behavioral therapy techniques and interactive education.