Lindsey Rachel Smith

Is BMI alone a sufficient outcome to evaluate interventions for child obesity

BACKGROUND BMI is often used to evaluate the effectiveness of childhood obesity interventions, but such interventions may have additional benefits independent of effects on adiposity. We investigated whether benefits to health outcomes following the Mind, Exercise, Nutrition…Do It! (MEND) childhood obesity intervention were independent of or associated with changes in zBMI. METHODS A total of 79 obese children were measured at baseline; 71 and 42 participants were followed-up at 6 and 12 months respectively, and split into four groups depending on magnitude of change in zBMI. Differences between groups for waist circumference, cardiovascular fitness, physical and sedentary activities, and self-esteem were investigated. RESULTS Apart from waist circumference and its z-score, there were no differences or trends across zBMI subgroups for any outcome. Independent of the degree of zBMI change, benefits in several parameters were observed in children participating in this obesity intervention. CONCLUSION We concluded that isolating a single parameter like zBMI change and neglecting other important outcomes is restrictive and may undermine the evaluation of childhood obesity intervention effectiveness.

Long-Term Outcomes following the MEND 7–13 Child Weight Management Program

BACKGROUND In the current study, we report outcomes 2.4 years from baseline in a random subsample of overweight and obese children who attended MEND 7-13 programs delivered in UK community settings under service level conditions. METHODS The study employed an uncontrolled pre-follow-up design. A total of 165 children were measured. Outcomes included anthropometry, parental perception of emotional distress, body esteem, and self-esteem. RESULTS Overall, there were significant improvements in all outcomes apart from BMI z-score. In boys, BMI z-score, waist circumference z-score, and psychometrics all improved. In girls, there were no statistically significant differences at 2.4 years, except for body esteem. CONCLUSIONS In real-world settings, the MEND intervention, when delivered by nonspecialists, may result in modest, yet positive, long-term outcomes. Subsequent research should focus on improving the outcome effect size, providing effective behavior change maintenance strategies, and further investigating the reasons behind the observed gender differences.

Assessing the short-term outcomes of a community-based intervention for overweight and obese children: The MEND 5-7 programme

Objective The aim of this study was to report outcomes of the UK service level delivery of MEND (Mind,Exercise,Nutrition...Do it!) 5-7, a multicomponent, community-based, healthy lifestyle intervention designed for overweight and obese children aged 5–7 years and their families. Design Repeated measures. Setting Community venues at 37 locations across the UK. Participants 440 overweight or obese children (42% boys; mean age 6.1 years; body mass index (BMI) z-score 2.86) and their parents/carers participated in the intervention. Intervention MEND 5-7 is a 10-week, family-based, child weight-management intervention consisting of weekly group sessions. It includes positive parenting, active play, nutrition education and behaviour change strategies. The intervention is designed to be scalable and delivered by a range of health and social care professionals. Primary and secondary outcome measures The primary outcome was BMI z-score. Secondary outcome measures included BMI, waist circumference, waist circumference z-score, childrens psychological symptoms, parenting self-efficacy, physical activity and sedentary behaviours and the proportion of parents and children eating five or more portions of fruit and vegetables. Results 274 (62%) children were measured preintervention and post-intervention (baseline; 10-weeks). Post-intervention, mean BMI and waist circumference decreased by 0.5 kg/m2 and 0.9 cm, while z-scores decreased by 0.20 and 0.20, respectively (p<0.0001). Improvements were found in childrens psychological symptoms (−1.6 units, p<0.0001), parent self-efficacy (p<0.0001), physical activity (+2.9 h/week, p<0.01), sedentary activities (−4.1 h/week, p<0.0001) and the proportion of parents and children eating five or more portions of fruit and vegetables per day (both p<0.0001). Attendance at the 10 sessions was 73% with a 70% retention rate. Conclusions Participation in the MEND 5-7 programme was associated with beneficial changes in physical, behavioural and psychological outcomes for children with complete sets of measurement data, when implemented in UK community settings under service level conditions. Further investigation is warranted to establish if these findings are replicable under controlled conditions.

Physical activity levels and motivational responses of boys and girls: A comparison of direct instruction and tactical games models of games teaching in physical education

The purpose of this study was to independently determine the levels of moderate-to-vigorous physical activity (MVPA) and self-determined motivation of both boys and girls as they participated in prolonged units of invasion games (i.e. 6–12 lessons) through two pedagogical models: direct instruction and the tactical games model (TGM). It was hypothesized that given the differences in domain interaction and lesson structure, both boys and girls would gain higher levels of physical activity (PA) and possess higher quality motivation during TGM-based lessons when compared to direct instruction lessons. Seventy-two children aged 11–12 years (42 boys, 30 girls) were randomly assigned to either a control or intervention group (TGM). Children wore RT3® triaxial accelerometers over a 12 week period to objectively measure time spent in MVPA. The System for Observing Fitness Instruction Time (SOFIT) tool was completed during each lesson to additionally assess lesson context information and teacher behaviour. SDT questionnaires were also completed, pre and post-intervention. Boys in the TGM condition displayed significantly higher levels of MVPA in both rugby and football activities in comparison to the control group although no significant differences in motivation were noted post-intervention. While girls in the TGM condition recorded comparable PA levels in the football sessions, they recorded significantly lower PA activity levels in the netball lessons. There were no significant differences in girls’ motivation post-intervention. It is recommended that future studies build on this research by continuing to examine PA and the quality of student motivation while using GCAs over prolonged unit lengths (i.e. greater than 12 lessons) using structural equation modelling techniques to assess the relationships between, and mediating influences of, SDT constructs on PA levels.

Physical education contributes to total physical activity levels and predominantly in higher intensity physical activity categories

Children’s engagement in physical activity of a vigorous intensity or higher is more effective at promoting cardiorespiratory fitness than moderate physical activity. It remains unclear how higher intensity physical activity varies between days when schoolchildren participate in physical education (PE) and non-PE days. The purpose of this study was to assess how PE contributes to sedentary behaviour and the intensity profile of physical activity accumulated on PE days compared to non-PE days. Fifty-three schoolchildren (36 girls, 11.7 ± 0.3 years) completed five-day minute-by-minute habitual physical activity monitoring using triaxial accelerometers to determine time spent sedentary (<1.5 Metabolic Equivalent of Tasks (METs)) and in light (1.5–2.9 METs), moderate (3–5.9 METs), vigorous (6–8.9 METs), hard (9–11.9 METs) and very hard intensity (≥12 METs) physical activity on PE days and non-PE days. Sedentary time was higher on non-PE days than on PE days (mean difference: 62 minutes, p < 0.001). Hard and very hard intensity physical activity was significantly higher on PE days compared with non-PE days (mean total difference: 33 minutes, all significant at p < 0.001). During the PE lesson, boys spent more time in hard (p < 0.01) and very hard (p < 0.01) physical activity compared to girls. Schoolchildren spent significantly more time in higher intensity physical activity and significantly less time sedentary on PE days than on non-PE days. As well as reducing sedentary behaviour, the opportunity to promote such health-promoting higher intensity physical activity in the school setting warrants further investigation.

Reducing prolonged sedentary time using a treadmill desk acutely improves cardiometabolic risk markers in male and female adults

ABSTRACT This study evaluated the acute effects of interrupting prolonged sitting with an accumulated 2 h of light-intensity walking on postprandial cardiometabolic risk markers. In this randomised crossover trial, 24 participants (twelve males) aged 18–55 years took part in two, 6.5 h conditions: 1) prolonged sitting (SIT) and 2) sitting interrupted hourly with 20 min light-intensity treadmill desk walking at between 1.2–3.5 km/h−1 (INT-SIT). Standardized meals were provided at 0 h and 3 h. Blood samples and blood pressure measures were taken hourly. Statistical analyses were completed using linear mixed models. Postprandial incremental area under the curve responses (mmol/L∙6.5 h) for glucose (4.52 [3.47, 5.56] and 6.66 [5.62, 7.71] for INT-SIT and SIT, respectively) and triglycerides (1.96 [0.96, 2.96] and 2.71 [1.70, 3.71] for INT-SIT and SIT, respectively) were significantly lower in INT-SIT than SIT. Mean systolic and diastolic blood pressure responses were lower by 3% and 4%, respectively, in INT-SIT than SIT (P < 0.05). There was no significant condition x sex interaction effect for any outcomes (P > 0.05). These findings suggest that interrupting sitting with an accumulated 2 h of light-intensity walking acutely improves cardiometabolic risk levels in males and females compared with prolonged sitting.

Middle and Elementary School Students’ Changes in Self-Determined Motivation in a Basketball Unit Taught using the Tactical Games Model

Abstract Studies examining student motivation levels suggest that this is a significant factor in students’ engagement in physical education and may be positively affected when teachers employ alternative pedagogical models such as game-centered approaches (GCAs). The aim of this study was to investigate changes in self-determined motivation of students as they participated in a GCA-basketball unit taught using the Tactical Games Model (TGM). Participants were 173 students (84 girls), 79 middle school (45 girls) and 94 (39 girls) elementary school students from four seventh and five fourth/fifth grade co-educational classes. Two teachers taught 32 (middle) and 33 (elementary) level one TGM basketball lessons. Need satisfaction and self-determined motivation data were collected using a previously validated instrument, while lesson context and teacher behavior data were recorded using systematic observation instruments. Repeated measures MANOVAs were employed to examine pre-posttest differences. Results revealed a significant main effect for time in need satisfaction for both middle (relatedness increased) and elementary school students (autonomy decreased) and a significant main effect in self-determined motivation for middle school students only (introjected regulation, external regulation, and amotivation all increased). Approximately 48%/42% (middle/elementary) of lesson time was game play, 22%/22% skill practice, 17%/17% management, and 13%/19% knowledge. The primary teacher behaviors used were instruction, management, specific observation, corrective feedback and modelling. Results indicate that it is important for future research to pay greater attention to the contextual factors associated with the application of the TGM, such as the students’ previous exposure to TGM lessons, and the teachers’ training and experience in utilizing the TGM. Indeed, results of the present study demonstrate that a longer-term commitment to the TGM is necessary to reduce controlling teacher behaviors, which will lead to positive changes in students’ need satisfaction and self-determined motivation. Future research is therefore needed to embrace this challenge to provide an increased evidence-base for GCAs such as the TGM.