Relationships between maturity status, physical activity and physical self-perceptions in primary school children

The aim of this study was to examine the influence of maturity status on primary school children's physical activity and physical self-perceptions. Altogether, 175 children (97 girls, 78 boys) aged 10.6 ± 0.3 years completed the Children and Youth Physical Self-Perception Profile and wore an ActiGraph accelerometer for five consecutive days to assess moderate-to-vigorous physical activity. Anthropometric measures were completed to estimate maturity status. A two-level, multi-level analysis was used to assess the influence of maturity status on moderate-to-vigorous physical activity and physical self-perceptions. Boys performed more moderate-to-vigorous physical activity than girls (P < 0.0001), but when the effect of maturity status was controlled the difference was reduced (P = 0.02). Significant differences between the sexes were also observed for physical self-perception sub-domains (boys > girls, P = 0.02 to 0.0001). When maturity status was added to the model, significant differences were no longer apparent for each sub-domain, with the exception of perceived strength. Significant interactions between gender and maturity status revealed that boys' physical self-perceptions improved with more advanced maturity status, whereas girls' self-perceptions decreased (P = 0.07 to 0.002). Significant differences between the sexes in moderate-to-vigorous physical activity and some domains of physical self-perceptions were reduced or no longer evident when the effect of maturity status was controlled. Maturity status may differentially influence boys' and girls' physical self-perceptions.

Relationships between measures of fitness, physical activity, body composition and vascular function in children

Background : The prevalence of obesity and physical inactivity in Western countries has increased rapidly. Both are modifiable risk factors for cardiovascular disease. Atherosclerosis begins in childhood and endothelial dysfunction is its earliest detectable manifestation.

Methods : We assessed flow-mediated dilation (FMD) in 129 children (75 female; 10.3 + 0.3 yrs; 54 male; 10.4; 0.3 yrs). FMD was normalised for differences in the eliciting shear rate stimulus between subjects (SR_AUC). Fitness was assessed as peak oxygen uptake during an incremental treadmill exercise test (VO₂peak). Body composition was measured using a dual-energy X-ray absorptiometry (DEXA) scan. Physical activity (PA) was assessed using Actigraph accelerometers. The cohort was split into tertiles according to FMD% and also FMD% corrected for SR_AUC to gain insight into the determinants of vascular function.

Results : Across the cohort, significant correlations were observed between FMD%/SR_AUC and DEXA percentage fat (r = −0.23, p = 0.009) and percentage lean mass (r = 0.21, p = 0.008), and also with PA performed at moderate-to-high intensity (r = 0.363, p = 0.001). For children in the lowest FMD%/SR_AUC tertile, a stronger relationship with all PA measures was observed, particularly with high intensity PA (r = 0.572, P = 0.003). Regression analysis revealed that high intensity PA was the only predictor of impaired FMD%/SR_AUC.

Conclusions : These data suggest that traditional risk factors for CHD in adult populations impact upon vascular function in young people. Furthermore, it appears that individuals with impaired FMD may benefit from performing high intensity PA, whereas no relationships exist between FMD and lower intensities of PA or between PA and FMD in those subjects who possess preserved vascular function a priori.

Transient response analysis of steel in concrete

A new approach is presented for the analysis of galvanostatically induced transients allowing for the rapid evaluation of the corrosion activity of steel in concrete. This method of analysis is based on the iterative fitting of a non-exponential model based on a modified KWW (Kohlrausch–Williams–Watt) formalism. This analysis yields values for the parameters related to corrosion such as the concrete resistance, polarisation resistance, interfacial capacitance and β, the non-ideality exponent.

Validity and reliability of instruments to assess potential mediators of children's physical activity : a systematic review

This paper aimed to (1) identify potential mediators reported in children's physical activity interventions; and (2) review the psychometric properties of measures of potential mediators included in such interventions. A systematic search of the literature was conducted and studies that reported potential mediators and/or the psychometric properties of measures of potential mediators were retrieved and reviewed. The studies were reviewed for the following psychometric properties: face/logical, construct, and criterion validity; and test–retest and internal consistency (factor analysis and Cronbach's α) reliability. Twenty-one potential mediators were identified from 24 published children's physical activity intervention studies; 17 individual, three social, and one physical environmental. Overall, there was considerable variation in the reporting of the psychometric properties of these measures. Reliability properties (specifically Cronbach's α) were more commonly reported than validity properties; however, for many potential mediators, the quality of these measures was low. Future studies should examine the psychometric properties of measures of potential mediators to ensure appropriate, valid and reliable instruments are used. This will assist in the ability to accurately determine the efficacy of physical activity interventions among children.

The analysis of café espresso using two-dimensional reversed phase–reversed phase high performance liquid chromatography with UV-absorbance and chemiluminescence detection

In this study, an activity based screening technique combining two-dimensional liquid chromatography (2DHPLC) with UV-absorbance and chemiluminescence detection was applied to study “Ristretto”, "Decaffeinatto” and “Volluto” espresso coffees. This technique, which coupled the separation power of 2DHPLC with the sensitivity and selectivity of the chemiluminescence detection, offers great potential for screening complex samples for antioxidant compounds. Detailed information regarding the complexity of the sample, and the variation between these three coffees could be obtained using this multidimensional-hyphenated method of analysis.

Environmental correlates of physical activity in Australian workplaces

Purpose – The workplace is an ideal setting to promote physical activity. The purpose of this study is to examine associations with physical activity at and around the workplace.
Design/methodology/approach – Participants were recruited from a random sample of employed adults (n ¼ 1; 107) in capital cities and major regional centres in Australia. Self-reported barriers and participation in physical activity at and around the workplace were assessed. A multivariable logistic regression model adjusting for age, sex, occupational status, and overall physical activity assessed the odds of being active in this setting.
Findings – Of participants, 61 percent perceived being active in the workplace. Those who perceived their work colleagues and managers to be physically active, and those who indicated that their workplace provides facilities to support them being active had higher odds of being physically active at or around the workplace.
Research limitations/implications – A poor response rate, physically active sample and cross-sectional analysis prevent inferences about the causality of the findings.
Originality/value – The paper provides evidence of the potential for the multiple levels of influence on physical activity at and around the workplace.

A Rasch analysis of the teachers music confidence scale

This article presents a new measure of teachers’ confidence to conduct musical activities with young children; Teachers Music Confidence Scale (TMCS). The TMCS was developed using a sample of 284 in-service and pre-service early childhood teachers in Hong Kong Special Administrative Region (HKSAR). The TMCS consisted of 10 musical activities. Teachers rated their confidence levels to conduct each activity on a scale from 1 (Not confident at all) to 5 (Very confident). An exploratory factor analysis retained a 10-item single factor that was replicated using confirmatory factor analysis procedures. All items of the TMCS fitted the Rasch model adequately. In-service teachers showed higher confidence levels to conduct several musical activities with young children than pre-service teachers. Implications of these findings for measuring teachers’ confidence to conduct musical activities with young children were discussed.

Analysis of dynamic strains in tibia during human locomotion based on flexible multibody approach integrated with magnetic resonance imaging technique

Bone is known to adapt to the prevalent strain environment while the variation in strains, e.g., due to mechanical loading, modulates bone remodeling, and modeling. Dynamic strains rather than static strains provide the primary stimulus of bone functional adaptation. The finite element method can be generally used for estimating bone strains, but it may be limited to the static analysis of bone strains since the dynamic analysis requires expensive computation. Direct in vivo strain measurement, in turn, is an invasive procedure, limited to certain superficial bone sites, and requires surgical implementation of strain gauges and thus involves risks (e.g., infection). Therefore, to overcome difficulties associated with the finite element method and the in vivo strain measurements, the flexible multibody simulation approach has been recently introduced as a feasible method to estimate dynamic bone strains during physical activity. The purpose of the present study is to further strengthen the idea of using the flexible multibody approach for the analysis of dynamic bone strains. Besides discussing the background theory, magnetic resonance imaging is integrated into the flexible multibody approach framework so that the actual bone geometry could be better accounted for and the accuracy of prediction improved.