Cross-sectional geometry of weight-bearing tibia in female athletes subjected to different exercise loadings

Summary The association of long-termsport-specific exercise loading with cross-sectional geometry of the weight-bearing tibia was evaluated among 204 female athletes representing five different exercise loadings and 50 referents. All exercises involving ground impacts (e.g., endurance running, ball games, jumping) were associated with thicker cortex at the distal and diaphyseal sites of the tibia and also with large diaphyseal cross-section, whereas the high-magnitude (powerlifting) and non-impact (swimming) exercises were not. Introduction Bones adapt to the specific loading to which they are habitually subjected. In this cross-sectional study, the association of long-term sport-specific exercise loading with the geometry of the weight-bearing tibia was evaluated among premenopausal female athletes representing 11 different sports.

Methods A total of 204 athletes were divided into five exercise loading groups, and the respective peripheral quantitative computed tomographic data were compared to data obtained from 50 physically active, non-athletic referents. Analysis of covariance was used to estimate the between-group differences.

Results At the distal tibia, the high-impact, odd-impact, and repetitive low-impact exercise loading groups had ~30% to 50% (p<0.05) greater cortical area (CoA) than the referents. At the tibial shaft, these three impact groups had ~15% to 20% (p<0.05) greater total area (ToA) and ~15% to 30% (p<0.05) greater CoA. By contrast, both the high-magnitude and repetitive non-impact groups had similar ToA and CoA values to the reference group at both tibial sites.

Conclusions High-impact, odd-impact, and repetitive lowimpact exercise loadings were associated with thicker cortex at the distal tibia. At the tibial shaft, impact loading was not only associated with thicker cortex, but also a larger cross-sectional area. High-magnitude exercise loading did not show such associations at either site but was comparable to repetitive non-impact loading and reference data. Collectively, the relevance of high strain rate together with moderate-to-high strain magnitude as major determinants of osteogenic loading of the weight-bearing tibia is implicated.

A comparative assessment of austempered ductile iron as a substitute in weight reduction applications

Manufacturing engineering has had to undergo drastic changes in the approach to material selection in order to meet new design challenges. In the automotive industry, researchers in their effort to reduce emissions and satisfy environmental regulations, have shifted their focus to new emerging materials such as high-strength aluminium alloys, metal matrix composites, plastics, polymers and of late, Austempered Ductile Iron (ADI). ADI is a good choice for design where the criterion is high performance at reduced weight and cost. The unique, ausferrite microstructure gives the material desirable material properties and an edge over other materials. A comparative study of ADI in terms of materials properties and machining characteristics with other materials is desirable to highlight the potential of the material. This paper focuses on a comparative assessment of material and machining characteristics of ADI for different applications. The properties under consideration are machinability, weight and cost savings and versatility. ADI has a higher strength-to-weight ratio than aluminium making it a ready alternative for material selection. In terms of machinability, there are some problems associated with machining of ADI due to its work hardening nature. This paper attempts to identify the possible potential applications of ADI, by critically reviewing specific applications such as machinability, overall economics and service.

Coagulation and nano-filtration: a hybrid system for the removal of lower molecular weight organic compounds (LMWOC)

The removal of lower molecular weight organic compounds (LMWOC) from water is of increasing concern. While, nano-fi ltration (NF) is a good option, it removes only a fraction of the LMWOC. In this paper, NF experiments were conducted to remove oxalic acid and diuron in combination with coagulation using poly-aluminum chloride (PAC) as the coagulant. The results showed that this hybrid treatment system was effective in removing oxalic acid where almost a 100% removal effi ciency of oxalic acid was achieved. However, using PAC as coagulant to remove diuron from water was not effective. In order to improve the removal efficiency of diuron, 0.02 M NaCl was added to diuron and a 40% increase in the removal of diuron was achieved. Higher removal of diuron was achieved when the solution was treated with reverse osmosis (RO) when compared to the nano-filtration.

Reducing unhealthy weight gain in Fijian adolescents : results of the Healthy Youth Healthy Communities study

Obesity is a significant problem among adolescents in Pacific populations. This paper reports on the outcomes of a 3-year obesity prevention study, Healthy Youth Healthy Communities, which was part of the Pacific Obesity Prevention in Communities project, undertaken with Fijian adolescents. The intervention was developed with schools and comprised social marketing, nutrition and physical activity initiatives and capacity building designed to reduce unhealthy weight, and the individual exposure period was just over 2-year duration. The evaluation incorporated a quasi-experimental, longitudinal design in seven intervention secondary schools near Suva (n = 874) and a matched sample of 11 comparison secondary schools from western Viti Levu (n = 2,062). There were significant differences between groups at baseline; the intervention group was shorter, weighed less, had a higher proportion of underweight and lower proportion of overweight, and better quality of life (Pediatric Quality of Life Inventory only). At follow-up, the intervention group had lower percentage body fat (-1.17) but also a lower increase in quality of life (Assessment of Quality of Life instrument: -0.02; Pediatric Quality of Life Inventory: -1.94) than the comparison group. There were no other differences in anthropometry, and behaviours’ changes showed a mixed pattern. In conclusion, this school-based health promotion programme lowered percentage body fat but did not reduce unhealthy weight gain or influence most obesity-promoting behaviours among Fijian adolescents. Despite growing evidence supporting the efficacy of community-based approaches to reduce obesity among children of European descent, findings from this study failed to demonstrate the efficacy of a community capacity-building approach among an adolescent sample drawn from a different sociocultural, economic and geographical context. Additional ‘top–down’ or other innovative approaches may be needed to reduce adolescent obesity in the Pacific.

Weight changes among preschool children project

A prospective methodological design was used to provide comprehensive evidence of the influence of parenting (mothers and fathers) on the patterns of preschool children’s weight gain. With the exception of the parent-child observational measure, measures of all predictor and outcome variables have been obtained for children aged 24 to 36 months at three time points: at recruitment and at 12 and 24 months post recruitment; parent-child interactions have been obtained during home visits at recruitment and 12 months post recruitment.

Paternal influences on children's weight gain : a systematic review

Childhood overweight and obesity rates have continued to rise globally, reaching epidemic proportions. Children's dietary patterns evolve within the context of the family and there are a number of pathways through which parents may shape children's dietary practices, including parent nutritional knowledge the types of foods that are made available to children, parental modeling of particular eating behaviors, and parent child-feeding practices. Most research examining these predictors has been undertaken with mothers as the primary caregivers, while fathers have received markedly less attention. This paper is a review of the literature on paternal influences on preschool children's weight gain, overweight and obesity. The results of this review indicate that fathers do influence preschool children's weight gain, overweight and obesity status. However, methodological limitations in the existing studies make direct and meaningful comparisons across studies difficult. The review further highlights the fact that fathers have been neglected in childhood obesity research.

Angiotensin converting enzyme inhibition lowers body weight and improves glucose tolerance in C57BL/6J mice maintained on a high fat diet

The renin–angiotensin system (RAS) is functional within adipose tissue and angiotensin II, the active component of RAS, has been implicated in adipose tissue hypertrophy and insulin resistance. In this study, captopril, an angiotensin converting enzyme (ACE) inhibitor that prevents angiotensin II formation, was used to study the development of diet-induced obesity and insulin resistance in obesity prone C57BL/6J mice. The mice were fed a high fat diet (w/w 21% fat) and allowed access to either water or water with captopril added (0.2 mg/ml). Body weight was recorded weekly and water and food intake daily. Glucose tolerance was determined after 11–12 weeks. On completion of the study (after 16 weeks of treatment), the mice were killed and kidney, liver, epididymal fat and extensor digitorum longus muscle (EDL) were weighed. Blood samples were collected and plasma analysed for metabolites and hormones. Captopril treatment decreased body weight in the first 2 weeks of treatment. Food intake of captopril-treated mice was similar to control mice prior to weight loss and was decreased after weight loss. Glucose tolerance was improved in captopril-treated mice. Captopril-treated mice had less epididymal fat than control mice. Relative to body weight, captopril-treated mice had increased EDL weight. Relative to control mice, mice administered captopril had a higher plasma concentration of adiponectin and lower concentrations of leptin and non-esterified fatty acids (NEFA). The results indicate that captopril both induced weight loss and improved insulin sensitivity. Thus, captopril may eventually be used for the treatment of obesity and Type 2 diabetes.

Body image, weight loss and muscle building among Tongan adolescents in Tonga and New Zealand

This study examined body image and associated behaviours among 48 adolescents (24 males, 24 females) in Tonga, as well as 48 Tongan adolescents (24 males, 24 females) living in New Zealand (NZ). There was a lack of focus on body weight and shape among adolescents in both countries. Males evidenced a high focus on muscles. Females wanted to lose weight and obtain a soft round body. There were very few differences in the body image or body change strategies of Tongan adolescents in Tonga or NZ. Sociocultural messages need to be explored further in order to better understand these findings.

Differential effects of natural palm oil, chemically and enzymatically-modified palm oil on weight gain, blood lipid metabolites and fat deposition in a pediatric pig model

Background: Increasing prevalence of obesity and overweight in the Western world, continue to be a major health threat and is responsible for increased health care costs. Dietary intervention studies show a strong positive association between saturated fat intake and the development of obesity and cardiovascular disease. This study investigated the effect of positional distribution of palmitic acid (Sn-1, 2 & 3) of palm oil on cardiovascular health and development of obesity, using weaner pigs as a model for young children.

Methods: Male and female weaner piglets were randomly allocated to 4 dietary treatment groups: 1) pork lard (LRD); 2) natural palm olein (NPO); 3) chemically inter-esterified PO (CPO) and 4) enzymatically inter-esterified PO (EnPO) as the fat source. Diets were formulated with 11% lard or with palm olein in order to provide 31% of digestible energy from fat in the diet and were balanced for cholesterol, protein and energy across treatments.

Results: From 8 weeks onwards, pigs on EnPO diet gained (P < 0.05) more weight than all other groups. Feed conversion efficiency (feed to gain) over the 12 week experimental period did not vary between treatment groups. Plasma LDL-C content and LDL-C/HDL-C ratio in pigs fed natural PO tended to be lower compared to all other diets. The natural PO lowered (P < 0.02) the plasma triglyceride (TG) content relative to the lard or EnPO diets, but was not different from the CPO diet. The natural PO diet was associated with lower (P < 0.05) saturated fat levels in subcutaneous adipose tissue than the CPO and EnPO diets that had lower saturated fat levels than the lard diet. Female pigs had lower lean and higher fat and fat:lean ratio in the body compared with male pigs. No difference in weight gain or blood lipid parameters was observed between sexes.

Conclusions: The observations on plasma TG, muscle and adipose tissue saturated fatty acid contents and back fat (subcutaneous) thickness suggest that natural palm oil may reduce deposition of body fat. In addition, dietary supplementation with natural palm oil containing palmitic acid at different positions in meat producing animals may lead to the production of meat and meat products with lower saturated fats. An increase in fat content and a decrease in lean content in female pigs resulted in an increased body fat:lean ratio but gender had no effect on blood lipid parameters or insulin concentrations.