The effect of acute caffeine ingestion on upper and lower body anaerobic exercise performance

The current study examined the effect of acute caffeine ingestion on mean and peak power production, fatigue index and rating of perceived exertion (RPE) during upper body and lower body Wingate anaerobic test (WANT) performance. Using a double-blind design, 22 males undertook one upper body and one lower body WANT, 60 min following ingestion of caffeine (5 mg*kg-1) and one upper body and one lower body WANT following ingestion of placebo (5 mg*kg-1 Dextrose). Peak power was significantly higher (P=.001) following caffeine ingestion in both upper and lower body WANT. Peak power and mean power was also significantly higher during lower body, compared to upper body WANTs irrespective of substance ingested. However, caffeine ingestion did not enhance mean power neither in upper nor lower-body WANT. There were no significant differences in mean fatigue index as a consequence of substance ingested or mode of exercise (all P>0.05). For RPE there was also a significant substance ingested X mode interaction (P = .001) where there were no differences in RPE between caffeine and placebo conditions in lower body WANTs but significantly lower RPE during upper body WANT in the presence of caffeine compared to placebo (P = .014). This is the first study to compare the effects of caffeine ingestion on upper and lower body 30-second WANT performance and suggests that caffeine ingestion in the dose of 5 mg*kg-1 ingested 60 min prior to exercise significantly enhances peak power when data from upper and lower body WANTs are combined

Investigating A Dose Response Relationship between High Fat Diet Consumption and the Contractile Performance of Isolated Mouse Soleus, EDL and Diaphragm Muscles

PurposeRecent evidence has demonstrated an obesity-induced, skeletal muscle-specific reduction in contractile performance. The extent and magnitude of these changes in relation to total dose of high-fat diet consumption remains unclear. This study aimed to examine the dose–response relationship between a high-fat diet and isolated skeletal muscle contractility.Methods120 female CD1 mice were randomly assigned to either control group or groups receiving 2, 4, 8 or 12 weeks of a high-calorie diet (N = 24). At 20 weeks, soleus, EDL or diaphragm muscle was isolated (n = 8 in each case) and isometric force, work loop power output and fatigue resistance were measured.ResultsWhen analysed with respect to feeding duration, there was no effect of diet on the measured parameters prior to 8 weeks of feeding. Compared to controls, 8-week feeding caused a reduction in normalised power of the soleus, and 8- and 12-week feeding caused reduced normalised isometric force, power and fatigue resistance of the EDL. Diaphragm from the 12-week group produced lower normalised power, whereas 8- and 12-week groups produced significantly lower normalised isometric force. Correlation statistics indicated that body fat accumulation and decline in contractility will be specific to the individual and independent of the feeding duration.ConclusionThe data indicate that a high-fat diet causes a decline in muscle quality with specific contractile parameters being affected in each muscle. We also uniquely demonstrate that the amount of fat gain, irrespective of feeding duration, may be the main factor in reducing contractile performance

The Effects of Low and Moderate Dose Caffeine Supplementation on Upper and Lower Body Maximal Voluntary Concentric and Eccentric Muscle Force

Despite the growing quantity of literature exploring the effect of caffeine on muscular strength, there is a dearth of data that directly explores differences in erogenicity between upper and lower body musculature and the dose response effect. The present study sought to investigate the effects of low and moderate dose caffeine on the maximal voluntary strength of the elbow flexors and knee extensors. Ten non-specifically strength trained, recreationally active participants (21 ± 0.3 yrs) completed the study. Using a randomised, counterbalanced and double blind approach, isokinetic concentric and eccentric strength was measured at 60 and 180 deg/s following administration of a placebo, 3 mg・kg−1 body mass caffeine and 6 mg・kg−1 body mass caffeine. There was no effect of caffeine on the maximal voluntary concentric and eccentric strength of the elbow flexors, or the eccentric strength of the knee extensors. Both 3 and 6 mg・kg−1 body mass caffeine caused a significant increase in peak concentric force of the knee extensors at 180 deg/s. No difference was apparent between the two concentrations. Only 6 mg・kg−1 body mass caused an increase in peak concentric force during repeated contractions. The results infer that the effective caffeine concentration to evoke improved muscle performance may be related to muscle mass and contraction type. The present work indicates that relatively low dose caffeine treatment may be effective for improving lower body muscular strength, but may have little benefit for the strength of major muscular groups of the upper body.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The Effect of Increasing Age on the Concentric and Eccentric Contractile Properties of Isolated Mouse Soleus and Extensor Digitorum Longus Muscles

There is currently a limited amount of literature investigating the age-related changes in eccentric muscle function in vitro. The present study uniquely uses the work loop technique, to better replicate in vivo muscle function, in the assessment of the age and muscle-specific changes in acute and sustained concentric and eccentric power and recovery. Whole soleus or EDL muscles were isolated from 10-week and 78-week old mice, and acute and sustained concentric and eccentric work loop power assessed. Despite an age-related increase in body and muscle mass, peak absolute power for both muscles was unaffected by age. Peak concentric power normalised to muscle mass declined significantly for each muscle, whilst peak normalised eccentric power declined only for soleus. Fatigue resistance and recovery for the soleus did not differ between age or contraction type. Older EDL was less resistant to concentric fatigue, but was better able to withstand sustained eccentric activity than young EDL. We have shown that age-related changes in muscle quality are more limited for eccentric function than concentric function. A greater bodily inertia is likely to further reduce in vivo locomotor performance in older animals.</p

Is the Ergogenicity of Caffeine Affected by Increasing Age? The Direct Effect of a Physiological Concentration of Caffeine on the Power Output of Maximally Stimulated EDL and Diaphragm Muscle Isolated From the Mouse

Caffeine is a well-established performance enhancing nutritional supplement in a young healthy population, however far less is known about how its ergogenicity is affected by increasing age. A recent review has highlighted the value of studies examining the direct effect of caffeine on isolated skeletal muscle contractility, but the present work is the first to assess the direct effect of 70µM caffeine (physiological maximum) on the maximal power output of isolated mammalian muscle from an age range representing developmental to early ageing. Method: Female CD1 mice were aged to 3, 10, 30 and 50 weeks (n = 20 in each case) and either whole EDL or a section of the diaphragm was isolated and maximal power output determined using the work loop technique. Once contractile performance was maximised, each muscle preparation was treated with 70µM caffeine and its contractile performance was measured for a further 60 minutes. Results: In both mouse EDL and diaphragm 70µM caffeine treatment resulted in a significant increase in maximal muscle power output that was greatest at 10 or 30 weeks (up to 5% &amp; 6% improvement respectively). This potentiation of maximal muscle power output was significantly lower at the early ageing time point, 50 weeks (up to 3% &amp; 2% improvement respectively), and in mice in the developmental stage, at 3 weeks of age (up to 1% &amp; 2% improvement respectively). Conclusion: Uniquely, the present findings indicate a reduced age specific sensitivity to the performance enhancing effect of caffeine in developmental and aged mice which is likely to be attributed to age related muscle growth and degradation, respectively. Importantly, the findings indicate that caffeine may still provide a substantial ergogenic aid in older populations which could prove important for improving functional capacity in tasks of daily living.Publisher Statement: The final publication is available at Springer via http://dx.doi.org/10.1007/s12603-016-0832-9  </p

Contemporary medical television and crisis in the NHS

This article maps the terrain of contemporary UK medical television, paying particular attention to Call the Midwife as its centrepiece, and situating it in contextual relation to the current crisis in the NHS. It provides a historical overview of UK and US medical television, illustrating how medical television today has been shaped by noteworthy antecedents. It argues that crisis rhetoric surrounding healthcare leading up to the passing of the Health and Social Care Act 2012 has been accompanied by a renaissance in medical television. And that issues, strands and clusters have emerged in forms, registers and modes with noticeable regularity, especially around the value of affective labour, the cultural politics of nostalgia and the neoliberalisation of healthcare

Worrying Leads to Reduced Concreteness of Problem Elaborations: Evidence for the Avoidance Theory of Worry

Both lay concept and scientific theory have embraced the view that nonpathological worry may be helpful for defining and analyzing problems. To evaluate the quality of problem elaborations, concreteness is a key variable. Two studies with nonclinical student samples are presented in which participants elaborated topics associated with different degrees of worry. In Study 1, participants' elaborations were assessed using problem elaboration charts; in Study 2, they were assessed using catastrophizing interviews. When participants' problem elaborations were rated for concreteness, both studies showed an inverse relationship between degree of worry and concreteness: The more participants worried about a given topic the less concrete was the content of their elaboration. The results challenge the view that worry may promote better problem analyses. Instead they conform to the view that worry is a cognitive avoidance response

High resolution spatial modelling of greenhouse gas emissions from land use change to energy crops in the UK

We implemented a spatial application of a previously evaluated model of soil GHG emissions, ECOSSE, in the United Kingdom to examine the impacts to 2050 of land-use transitions from existing land use, rotational cropland, permanent grassland or woodland, to six bioenergy crops; three ‘first-generation’ energy crops: oilseed rape, wheat and sugar beet, and three ‘second-generation’ energy crops: Miscanthus, short rotation coppice willow (SRC) and short rotation forestry poplar (SRF). Conversion of rotational crops to Miscanthus, SRC and SRF and conversion of permanent grass to SRF show beneficial changes in soil GHG balance over a significant area. Conversion of permanent grass to Miscanthus, permanent grass to SRF and forest to SRF shows detrimental changes in soil GHG balance over a significant area. Conversion of permanent grass to wheat, oilseed rape, sugar beet and SRC and all conversions from forest show large detrimental changes in soil GHG balance over most of the United Kingdom, largely due to moving from uncultivated soil to regular cultivation. Differences in net GHG emissions between climate scenarios to 2050 were not significant. Overall, SRF offers the greatest beneficial impact on soil GHG balance. These results provide one criterion for selection of bioenergy crops and do not consider GHG emission increases/decreases resulting from displaced food production, bio-physical factors (e.g. the energy density of the crop) and socio-economic factors (e.g. expenditure on harvesting equipment). Given that the soil GHG balance is dominated by change in soil organic carbon (SOC) with the difference among Miscanthus, SRC and SRF largely determined by yield, a target for management of perennial energy crops is to achieve the best possible yield using the most appropriate energy crop and cultivar for the local situation