4,307 research outputs found
Turning up the heat: can post-exercise hot water immersion be used to manipulate acute physiological responses & chronic adaptation following resistance training?
Resistance training is a modality of exercise that is a staple part of strength and conditioning programmes as it offers benefits to competitive performance. Despite the positive adaptations which occur through performing regular training sessions over time, a single bout of resistance exercise results in a series of acute physiological responses. These may negatively impact performers in the hours and days post-exercise, although several questions exist with regards to appropriately characterising the magnitude and time course of this response which relate to the sensitivity of the measures which are used to do so. The context-dependent dichotomy between recovery and adaptation has fuelled much discussion in the scientific literature and has recently been articulated within the concept of hormesis, with post-exercise strategies aiming to optimise the exercise stimulus. The complex interplay between acute physiological responses and recovery/adaptation requires further investigation as recovery remains one of the least understood aspects of the exercise-adaptation cycle. Hot water immersion (HWI) is a form of heat therapy which is anecdotally reported to be used by athletes, whilst the modern advent of Jacuzzis and immersion pools in an increasing number of leisure facilities make it an easily accessible strategy. HWI may influence acute physiological responses within the recovery/adaptation paradigm but has received limited attention, while no research has investigated the chronic use of HWI alongside a resistance training programme. Therefore, the aim of this course of investigations was to elucidate the effects of HWI on acute physiological responses as well as recovery/adaptation to resistance exercise in a trained cohort. This research initially critically evaluated the literature investigating the use of HWI to identify several gaps worthy of further investigation. Subsequently, three experimental chapters were designed and conducted to assess the impact of HWI to manipulate acute physiological responses following resistance exercise and the influence on recovery/adaptation.
Study 1: The aim of this investigation was to assess the usefulness of a variety of measures that are used to detail acute physiological responses following resistance exercise. The study utilised a crossover design, assessed measures through a relevant timescale (i.e. 2 h – 96 h post-exercise), recruited trained participants and employed a real-world exercise modality to enhance the ecological validity of the findings. The results suggest that several measures were able to demonstrate clear effects following resistance exercise. Additionally, the results provided a profile relating to the magnitude of change and time course for these measures with optimal sampling points identified which informed the acute physiological response measures used in subsequent chapters.
Study 2: The aim of this study was to investigate the effect of HWI on acute physiological responses and recovery following resistance exercise. The main findings demonstrated that HWI is a viable means of heat therapy that can support a greater intramuscular temperature following resistance exercise. The elevated intramuscular temperature may have manipulated inflammatory processes. Although changes in other acute physiological response markers were independent of changes in intramuscular temperature associated with HWI. These results represent the first investigation into the acute physiological responses of a ‘real-world’ HWI protocol following resistance exercise, alongside the use of a trained cohort, applied exercise session and utilising good nutritional practice.
Study 3: This chapter aimed to investigate the effect of HWI on acute physiological responses and training adaptation following a 10-week resistance training programme. The main findings demonstrated that HWI (i) augmented long-term gains in strength, (ii) had no effect on the post-training increase in lower body lean mass (iii) elicited an accelerated recovery of muscle function and soreness in the acute post-exercise period following training, and (iv) attenuated the increase of markers of inflammation and muscle cell disruption following training compared to passive recovery (PAS). Collectively, these findings suggest that at the end of a 10-week training programme, HWI manipulates acute physiological responses to hasten post-exercise recovery. This may have positively impacted an individual’s ability to train in subsequent sessions, leading to an accumulated training stimulus that induced small but worthwhile improvements in strength.
This course of investigation has provided novel information as to how HWI manipulates acute physiological responses and the subsequent impact on recovery/adaptation following resistance exercise. In addition to identifying sensitive measures and recommended sampling points for acute physiological responses, this research provides the first evidence which suggests (i) a ‘real world’ HWI protocol can maintain an elevated intramuscular temperature and blood flow following resistance exercise, (ii) acute physiological responses can be manipulated by HWI to enhance recovery during a training programme, and (iii) the HWI-associated benefits to training enabled small but worthwhile enhancements in strength adaptations following a resistance training programme. This series of studies utilised a ‘real-world’ HWI protocol, alongside the use of a trained cohort, applied exercise session and good nutritional practice, enhancing the ecological validity of this thesis. Further work is warranted to optimise the HWI protocol and widen the scope of application to other cohorts and with different exercise modalities, as well as deepen mechanistic knowledge. However, the positive findings from this thesis provide physiologists with rationale for utilisation of HWI alongside resistance training in their applied practice
Telemedicine: An expanding new science on land and sea
Several medical and technical men in San Diego County are concerned with the need in many rural communities for a 24-hour day, 7-days a week access to adequate medical care. People isolated from urban areas by travel-times of 40-minutes tend to delay seeking early and effective medical care. The authors were able to assemble quality technology which permits narrow-band video-pictures, better known in the CB trade as ROBOT slow-scan television (SSTV), to be transmitted over telephone lines, by micro-wave, through satellite-bounce, or by HF-radio. These 'ROBOT' pictures can be accompanied with explanatory audio communication and with diagnostic signals from electronic instruments
Tackling unemployment: Europe's successes and failures.
Why has unemployment fallen in some European countries but not in others? To answer this question, Richard Layard, Stephen Nickell and Richard Jackman revisit their landmark analysis of macroeconomic performance and the labour market.
Ethical and compliance-competence evaluation: a key element of sound corporate governance
Motivated by the ongoing post-Enron refocusing on corporate governance and the shift by the Financial Services Authority (FSA) in the UK to promoting compliance- competence within the financial services sector, this paper demonstrates how template analysis can be used as a tool for evaluating compliance-competence. Focusing on the ethical dimension of compliance-competence, we illustrate how this can be subjectively appraised. We propose that this evaluation technique could be utilised as a starting point in informing senior management of corporate governance issues and be used to monitor and demonstrate key compliance and ethical aspects of an institution to external stakeholders and regulators
Two-Dimensional Intercomparison of Stratospheric Models
A detailed record is provided for the examination of fundamental differences in photochemistry and transport among atmospheric models. The results of 16 different modeling groups are presented for several model experiments
Discussion quality diffuses in the digital public square
Studies of online social influence have demonstrated that friends have
important effects on many types of behavior in a wide variety of settings.
However, we know much less about how influence works among relative strangers
in digital public squares, despite important conversations happening in such
spaces. We present the results of a study on large public Facebook pages where
we randomly used two different methods--most recent and social feedback--to
order comments on posts. We find that the social feedback condition results in
higher quality viewed comments and response comments. After measuring the
average quality of comments written by users before the study, we find that
social feedback has a positive effect on response quality for both low and high
quality commenters. We draw on a theoretical framework of social norms to
explain this empirical result. In order to examine the influence mechanism
further, we measure the similarity between comments viewed and written during
the study, finding that similarity increases for the highest quality
contributors under the social feedback condition. This suggests that, in
addition to norms, some individuals may respond with increased relevance to
high-quality comments.Comment: 10 pages, 6 figures, 2 table
Simultaneous conduction and valence band quantisation in ultra-shallow, high density doping profiles in semiconductors
We demonstrate simultaneous quantisation of conduction band (CB) and valence
band (VB) states in silicon using ultra-shallow, high density, phosphorus
doping profiles (so-called Si:P -layers). We show that, in addition to
the well known quantisation of CB states within the dopant plane, the
confinement of VB-derived states between the sub-surface P dopant layer and the
Si surface gives rise to a simultaneous quantisation of VB states in this
narrow region. We also show that the VB quantisation can be explained using a
simple particle-in-a-box model, and that the number and energy separation of
the quantised VB states depend on the depth of the P dopant layer beneath the
Si surface. Since the quantised CB states do not show a strong dependence on
the dopant depth (but rather on the dopant density), it is straightforward to
exhibit control over the properties of the quantised CB and VB states
independently of each other by choosing the dopant density and depth
accordingly, thus offering new possibilities for engineering quantum matter.Comment: 5 pages, 2 figures and supplementary materia
A Cytotoxic, Co-operative Interaction Between Energy Deprivation and Glutamate Release From System x\u3csub\u3ec\u3c/sub\u3e\u3csup\u3e−\u3c/sup\u3e Mediates Aglycemic Neuronal Cell Death
The astrocyte cystine/glutamate antiporter (system xc−) contributes substantially to the excitotoxic neuronal cell death facilitated by glucose deprivation. The purpose of this study was to determine the mechanism by which this occurred. Using pure astrocyte cultures, as well as, mixed cortical cell cultures containing both neurons and astrocytes, we found that neither an enhancement in system xc− expression nor activity underlies the excitotoxic effects of aglycemia. In addition, using three separate bioassays, we demonstrate no change in the ability of glucose-deprived astrocytes—either cultured alone or with neurons—to remove glutamate from the extracellular space. Instead, we demonstrate that glucose-deprived cultures are 2 to 3 times more sensitive to the killing effects of glutamate or N-methyl-D-aspartate when compared with their glucose-containing controls. Hence, our results are consistent with the weak excitotoxic hypothesis such that a bioenergetic deficiency, which is measureable in our mixed but not astrocyte cultures, allows normally innocuous concentrations of glutamate to become excitotoxic. Adding to the burgeoning literature detailing the contribution of astrocytes to neuronal injury, we conclude that under our experimental paradigm, a cytotoxic, co-operative interaction between energy deprivation and glutamate release from astrocyte system xc− mediates aglycemic neuronal cell death
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