Objectively assessed physical activity and weight status of primary school children in Germany with and without migration backgrounds.

OBJECTIVES: Many children are insufficiently active, and children with a migration background appear to be even less active and at a higher risk of developing obesity. This study evaluated the weight status, and the frequencies and intensities of objectively assessed physical activity (PA) of children with and without a migration background. STUDY DESIGN: Cross-sectional study. METHODS: PA was assessed objectively for 6 days in 273 children (aged 7.1 ± 0.6 years). In total, 74 children (27%) were classified as having a migration background. PA was grouped in light and moderate-to-vigorous (MVPA) intensities. Body mass index (BMI) percentiles (BMIPCT) were determined. RESULTS: Children without a migration background spent more time in MVPA compared with children with a migration background (138.2 ± 62.6 vs 121.7 ± 54.9 min, respectively; P < 0.01). On weekends, time in MVPA decreased significantly for all children (112.3 ± 66.0 min, P < 0.01), especially for children with a migration background (97.7 ± 56.7 min, P < 0.01). Children with a migration background displayed significantly higher BMIPCT than children without a migration background (55.7 ± 29.6 vs 44.3 ± 26.8, respectively; P < 0.01) and were significantly more often overweight and/or obese (13.5% vs 8.5%, respectively; P < 0.02). CONCLUSIONS: Children with a migration background are less physically active and more often overweight, resulting in higher risks of developing secondary diseases. The results of this study should be considered when designing interventions to increase PA in children with a migration background. TRIAL REGISTRATION: German Clinical Trials Register (DRKS), DRKS-ID: DRKS00000494.

Correlates of habitual physical activity and organized sports in German primary school children.

OBJECTIVES: The increased prevalence of childhood obesity has also been attributed to low physical activity (PA) levels. Understanding factors affecting child PA levels is especially important considering the benefits PA offers to youth. STUDY DESIGN: This study therefore examined different correlates affecting habitual PA and sports participation in primary school children. METHODS: Height and weight were measured during a school visit in 1714 children (7.1 ± .6 years). PA and behavioural correlates were assessed by parental questionnaire. The effect of various correlates on PA as well as participation in organized sports was assessed using logistic regression analysis. RESULTS: Significant correlates of PA and sports participation were engagement in sporting activities outside of clubs and children's weight status. Playing outdoors for more than 60 min/day was significant for PA, having well educated parents and being male. Participation in sports was influenced by children's media consumption, active travel to school and having active parents. No influence was found for migration, income, parental weight status and health consciousness. CONCLUSION: In this study, a multiplicity of independent correlates of PA and sports participation, which require a broad approach to promote an active lifestyle, have been considered. Understanding these factors might support the development of effective health-promoting interventions.

[Development and implementation of a state-wide "train the trainer" model of the school-based prevention programme "Join the Healthy Boat - Primary School"]. / Entwicklung und Implementierung eines landesweiten Multiplikatorensystems zur flächendeckenden Umsetzung des schulbasierten Präventionsprogramms "Komm mit in das gesunde Boot - Grundschule"

STUDY AIM: This paper shows how a state-wide health-promotion intervention at primary schools can be implemented by considering the example of the programme "Join the Healthy Boat - Primary School". Additionally, it is illustrated how quality control throughout the whole process can be incorporated. METHODS: To operate long-term and target-group orientated in the whole state of Baden-Württemberg, the school-based prevention programme "Join the Healthy Boat" uses a "train the trainer" model. The trainers are teachers who were instructed by the project team. In the school year 2009/10, these trainers offered quadrinominal training courses for further teachers. Every urban and rural district is covered by 1 trainer. The trainers evaluated the 6 preparatory training courses they had been given using questionnaires. The following 4 training courses the trainers offered to the teachers were reviewed by the trainers as well as the teachers using questionnaires, too. Additionally, at the end of the school year 2009/10, the teachers completed a questionnaire about their satisfaction regarding the programme itself and the work with the trainer. RESULTS: During the school year 2009/10, 453 teachers were trained by 32 trainers. According to indications on the questionnaires about the preparatory training courses, all trainers felt themselves "very well" or "well" prepared for their task. The teachers evaluated the expertise of the respective trainer, the quality of the training courses and the satisfaction with the programme itself throughout highly. CONCLUSION: Based on the excellent results of the process evaluation and the programme's wide coverage, an adoption of a "train the trainer" model seems worthwhile for other school-based prevention programmes, as well.

Optimization of the stress distribution in ceramic femoral heads by means of finite element methods.

Ceramic ball heads for total hip replacement are highly loaded in vivo and must meet the sternest requirements concerning strength and safety. High stresses inside the ball head originate from the press fit between the conical stem (made of titanium alloy or steel) and the borehole of the ball. The aim of this study was the development of an optimized contour at the fillet inside the ball head by means of numerical methods, in order to reduce local stress concentrations. The computer-aided optimization method was applied on the customary engineering fillet radius to reduce local stress peaks. The local notch stress of the examined ball head design was reduced by up to 27 per cent for the relevant load cases. Verification by rupture testing of prototypes turned out to be difficult for axisymmetric load cases, since the static fracture load is governed by the hoop stresses in the contact area of the taper (global maximum), thus making it difficult to prove a local improvement. The sensitivity of the design to asymmetric loading was clearly shown (varying the load angle and bearing type). Stress relocation in the ball-stem interface at higher burst loads indicated the necessity of optimizing each ceramic femoral head design individually (i.e. for different borehole depths).

Influence of contaminants in the stem-ball interface on the static fracture load of ceramic hip joint ball heads.

The probability of in-vivo failure of ceramic hip joint implants is very low (0.05-0.004 per cent). Besides material flaws and overloading, improper handling during implantation may induce fractures of the ceramic ball head in the long term. This study focuses on the influence of contaminants located in the stem-ball interface and on the use of damaged metal tapers on the strength of ceramic ball heads. Mechanical tests on alumina ball heads according to the standard ISO 7206-10 were performed to identify their effect on the static fracture load. A decrease of up to 90 per cent with respect to the reference static fracture load was found when contaminants such as bone chips, soft tissue, or blood were present. Reductions of 57 per cent and 27 per cent were observed for deformed stem cross-sections (from circular to elliptical) and for flattened stems respectively, making deformed stems another influential parameter. Since any alteration of the interface between the metal taper and the ceramic ball head yields a nonuniform load introduction and hence results in stress concentrations, its presence has to be avoided.