213 research outputs found

    Rugby-specific small-sided games training is an effective alternative to stationary cycling at reducing clinical risk factors associated with the development of type 2 diabetes: A randomized, controlled trial

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    © 2015 Mendham et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Introduction: The present study investigated whether rugby small-sided games (SSG) could be an effective alternative to continuous stationary cycling (CYC) training at reducing clinical risk factors associated with the development of type 2 diabetes mellitus (T2DM). Methods: Thirty-three middle-aged (48.6±6.6y), inactive men were randomized into a CYC (n=11), SSG (n=11), or control (CON, n=11) group. Participants trained 3d·wk-1 for 8 weeks, while control participants maintained normal activity and dietary patterns. Exercise duration was matched between groups, which involved CYC or SSG (four quarters, interspersed with 2- min passive recovery). Both training programs were designed to induce similar internal loads of maximal heart rate (∼80-85%HRmax) and rating of perceived exertion. Pre- and post-intervention testing included dual-energy x-ray absorptiometry scan, graded exercise test, fasting 2h oral glucose tolerance test and resting muscle biopsy. Western blotting was used to assess the content of skeletal muscle proteins associated with mitochondrial biogenesis and glucose regulation. Results: Both CYC and SSG increased VO2 at 80%HRmax, and reduced glycated haemoglobin, glucose area under the curve (AUC; SSG, -2.3±2.4; CYC -2.2±1.6 mmol·L1(120min)1; p1(120min)1; p0.05). There were no differences within or between conditions for protein content of peroxisome proliferator-activated receptor gamma coactivator-1α, sirtuin-1, p53, glucose transporter-4, protein kinase AKT/PKB, myocyte enhancer factor 2A, mitochondrial transcription factor, nuclear respiratory factor (NRF)-1, NRF-2 or mitochondrial complexes I-V (p>0.05). Conclusion: Rugby small-sided games is an effective alternative to continuous cycling for improving metabolic risk-factors associated with the prevention of T2DM. Despite such positive adaptations in clinical risk factors, there were no changes in the content of skeletal muscle proteins associated with glucose regulation and mitochondrial biogenesis. Trial Registration: Australian New Zealand Clinical Trial Registry ACTRN1261300087471

    Is the reputation of Eucalyptus plantations for using more water than Pinus plantations justified?

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    The effect of Eucalyptus plantations on water balance is thought to be more severe than for commercial alternatives such as Pinus species. Although this perception is firmly entrenched, even in the scientific community, only four direct comparisons of the effect on the water balance of a Eucalyptus species and a commercial alternative have been published. One of these, from South Africa, showed that Eucalyptus grandis caused a larger and more rapid reduction in streamflow than Pinus patula. The other three, one in South Australia and two in Chile, did not find any significant difference between the annual evapotranspiration of E. globulus and P. radiata after canopy closure. While direct comparisons are few, there are at least 57 published estimates of annual evapotranspiration of either the Eucalyptus or Pinus species. This paper presents a meta-analysis of these published data. Zhang et al. (2004) fitted a relationship between the vegetation evaporation efficiency and the climate wetness index to published data from catchment studies and proposed this approach for comparing land uses. We fitted this model to the published data for Eucalyptus and Pinus and found that the single parameter of this model did not differ significantly between the two genera (p = 0.48). This was also the case for all parameters of an exponential relationship between evapotranspiration and rainfall (p = 0.589) and a linear relationship between the vegetation evaporation index and rainfall (p = 0.155). These results provide strong evidence that, for a given climate wetness index, the two genera have similar annual water use. The residuals compared to the model of Zhang et al. (2004) were significantly correlated with soil depth for Eucalyptus, but this was not the case for Pinus. For Eucalyptus, the model overestimates the vegetation evaporation efficiency on deep soils and underestimates the vegetation evaporation efficiency on shallow soils

    Is the reputation of Eucalyptus plantations for using more water than Pinus plantations justified?

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    The effect of Eucalyptus plantations on water balance is thought to be more severe than for commercial alternatives such as Pinus species. Although this perception is firmly entrenched, even in the scientific community, only four direct comparisons of the effect on the water balance of a Eucalyptus species and a commercial alternative have been published. One of these, from South Africa, showed that Eucalyptus grandis caused a larger and more rapid reduction in streamflow than Pinus patula. The other three, one in South Australia and two in Chile, did not find any significant difference between the annual evapotranspiration of E. globulus and P. radiata after canopy closure. While direct comparisons are few, there are at least 57 published estimates of annual evapotranspiration of either a Eucalyptus or Pinus species. This paper presents a meta-analysis of these published data. Zhang et al. (2004) fitted a relationship between the crop factor and the climate wetness index to published data from catchment studies and proposed this approach for comparing land uses. We fitted the same model to the published data for Eucalyptus and Pinus and found that the single parameter of this model did not differ significantly between the two genera (p=0.48). This implies that for a given climate wetness index the two genera have similar annual water use. The residuals compared to this model were significantly correlated with soil depth for Eucalyptus, but this was not the case for Pinus. For Eucalyptus the model overestimates the crop factor on deep soils and underestimates the crop factor on shallow soils.</p

    Exercise intervention alters HDL subclass distribution and function in obese women

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    Background Obesity is associated with a change in high-density lipoprotein (HDL) function and subclass. Exercise training reduces cardiovascular risk in obese patients. We aimed to explore the effect of an exercise training stimulus on HDL functionality and subclass in obese women. Methods Thirty-two obese black South African women were randomly assigned to exercise (combined aerobic and resistance exercise) or control (no exercise) conditions for 12-weeks. Pre- and post-testing included venous blood sampling for analysis of lipid profile and HDL functionality, by measuring cellular cholesterol efflux capacity, reduction in endothelial vascular cell adhesion molecule (VCAM) expression (anti-inflammatory function), paraoxonase (PON) (antioxidative function) and platelet activating factor acetylhydrolase (PAF-AH) activities (anti-thrombotic function). PON-1 and PAF-AH expression were determined in serum and in isolated HDL using Western blotting. Levels of large, intermediate and small HDL subclasses were measured using the Lipoprint® system. Results Exercise training resulted in a decrease in body mass index (− 1.0 ± 0.5% vs + 1.2 ± 0.6%, p = 0.010), PON activity (− 8.7 ± 2.4% vs + 1.1 ± 3.0%, p = 0.021), PAF-AH serum expression (− 22.1 ± 8.0% vs + 16.9 ± 9.8, p = 0.002), and the distribution of small HDL subclasses (− 10.1 ± 5.4% vs + 15.7 ± 6.6%, p = 0.004) compared to controls. Exercise did not alter HDL cellular cholesterol efflux capacity and anti-inflammatory function. Conclusions These results demonstrate the potential for exercise training to modify HDL subclass distribution and HDL function in obese women. Trial registration Clinical trials number: PACTR201711002789113

    Circulating and Adipose Tissue Fatty Acid Composition in Black South African Women with Obesity: A Cross-Sectional Study

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    Background and Aims: During positive energy balance, excess lipid storage in subcutaneous adipose tissue (SAT) is associated with increased lipolysis. Elevated circulating fatty acid (FA) concentrations from both SAT lipolysis and dietary fat intake may result in visceral adipose tissue (VAT) accumulation, impairment of glucose metabolism, altogether increasing obesity-associated metabolic risks. We aimed to test the hypothesis that FA composition of red blood cell total phospholipids (RBC-TPL) and SAT is associated with body fat centralisation (VAT/SAT ratio) and insulin sensitivity (SI) in black South African women with obesity. Methods: Participants’ (n = 41) body fat composition and distribution, SI, and RBC-TPL, abdominal and gluteal SAT (gSAT) FA composition (gas-liquid chromatography) were measured. Results: RBC-TPL contained higher proportions of saturated fatty acids (SFAs) than SAT (p < 0.001), which were associated with lower SI (p < 0.05). Mono-unsaturated fatty acids (MUFAs) and stearoyl-CoA desaturase-1 (SCD1)-16 were lower, while poly-unsaturated fatty acids (PUFAs), and delta-5 and delta-6 desaturase indices were higher in RBC-TPL than SAT (p < 0.001). Interestingly, FA profiles differed between SAT depots with higher SFAs and lower MUFAs, SCD1-16 and SCD1-18 indices in abdominal compared to gluteal SAT (p < 0.01). In both SAT depots, higher SFAs and lower PUFAs (n-3 and n-6) correlated with lower VAT/SAT ratio; and lower PUFAs (n-3 and n-6) and higher total MUFA correlated with higher SI. Conclusion: Our findings confirm the relationships between the FA composition of RBC-TPL and SAT and metabolic risk in black women with obesity, which are dependent on both the FA class, and the tissue type/blood compartment in which they are distributed

    Exercise training results in depot-specific adaptations to adipose tissue mitochondrial function

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    We assessed differences in mitochondrial function in gluteal (gSAT) and abdominal subcutaneous adipose tissue (aSAT) at baseline and in response to 12-weeks of exercise training; and examined depot-specific associations with body fat distribution and insulin sensitivity (S-I). Obese, black South African women (n = 45) were randomized into exercise (n = 23) or control (n = 22) groups. Exercise group completed 12-weeks of aerobic and resistance training (n = 20), while the control group (n = 15) continued usual behaviours. Mitochondrial function (high-resolution respirometry and fluorometry) in gSAT and aSAT, SI (frequently sampled intravenous glucose tolerance test), body composition (dual-energy X-ray absorptiometry), and ectopic fat (MRI) were assessed pre- and post-intervention. At baseline, gSAT had higher mitochondrial respiratory capacity and hydrogen peroxide (H2O2) production than aSAT (p &lt; 0.05). Higher gSAT respiration was associated with higher gynoid fat (p &lt; 0.05). Higher gSAT H2O2 production and lower aSAT mitochondrial respiration were independently associated with lower SI (p &lt; 0.05). In response to training, S-I improved and gynoid fat decreased (p &lt; 0.05), while H2O2 production reduced in both depots, and mtDNA decreased in gSAT (p &lt; 0.05). Mitochondrial respiration increased in aSAT and correlated with a decrease in body fat and an increase in soleus and hepatic fat content (p &lt; 0.05). This study highlights the importance of understanding the differences in mitochondrial function in multiple SAT depots when investigating the pathophysiology of insulin resistance and associated risk factors such as body fat distribution and ectopic lipid deposition. Furthermore, we highlight the benefits of exercise training in stimulating positive adaptations in mitochondrial function in gluteal and abdominal SAT depots

    EverFarm® - Climate adapted perennial-based farming systems for dryland agriculture in southern Australia

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    Australian dryland agriculture will be affected by climate change in a number of ways. First, higher temperatures and changes to rainfall are likely to create greater variability of crop yields and livestock productivity. Second, government policies introduced to mitigate greenhouse gas emissions are likely to influence production costs and commodity prices. Third, global trade patterns are likely to alter as populations increase, and as climate change continues to affect producers and consumers worldwide. This will create both challenges and opportunities for Australian agriculture. Farmers will have to respond to the additional challenge of climate change even when it is compounded by existing long term stresses associated with declining terms of trade, climate variability and existing environmental issues. Investing in new land-use options to combat climate change, with their associated risks, is made more difficult by being set against a backdrop of declining profitability. The opportunity to create transformational change in farming enterprises was tested by combining the multiple components of the potential future perennial‐based dryland farming systems and assessing their expected contribution to climate change adaptation. This project has found that adopting perennial pastures for livestock grazing and tree crops for biomass production, when planted on appropriate soils, can improve profitability when compared to the existing land uses facing a changing climate. In some farming systems increased cropping is likely to result in improved future farm profits. This work demonstrated that Mallees as a biomass tree crop can be cohesively integrated into existing farming systems with minimal interruption to normal operations of livestock and cropping enterprises. A woody biomass crop can be profitable and diversify revenue risk by enabling farmers to supply biomass and sequester carbon to relevant markets. This work demonstrates suitable designs of a mallee belt planting layout that minimizes costs and maximizes benefits when planted in appropriate agro‐climatic zones and where there are adequate soil conditions. Knowledge developed from this work will help build farmers capacity about climate change adaptation and assist in achieving positive social, environmental and economic outcomes

    The football is medicine plaform-scientific evidence, large-scale implementation of evidence-based concepts and future perspectives

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    The idea that football can be used as therapy and as a high-intensity and literally breath-taking training regime goes back centuries. To take one prominent example, the French philosopher Voltaire describes in the Book of Fate (1747), how a patient is cured by playing with a sacred football: “… full-blown and carefully covered with the softest Leather. You must kick this Bladder, Sir, once a Day about your Hall for a whole Hour together, with all the Vigour and Activity you possibly can”, “Ogul, upon making the first Experiment, was ready to expire for want of Breath”, “In short, our Doctor in about 8 days Time, performed an absolute Cure. His Patient was as brisk, active and gay, as One in the Bloom of his Youth.”1 Today, Voltaire and his main character, philosopher Zadig, have been proved right: Football is indeed a breath-taking activity and it can be used as therapy. Albeit today's recommendations suggest a lower training frequency, longer training periods and encourage group-based training, and say that any football can be applied
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