939 resultados para blood lactate concentration


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Introduction: A systematic approach to managing the training of elite athletes is supported by accurate training load measurement. However, quantifying the training of elite Australian rowers is complex due to unique challenges: 1) the multi-centre, multi-state structure of the national program; 2) the variety of training undertaken, incorporating rowing-specific and non-specific modalities, with continuous and interval efforts that span the full intensity spectrum; and 3) the limitations of existing quantification methods for capturing total training loads undertaken from varied training. These challenges highlighted a need to create a consistent, location-independent framework for prescribing training in elite rowing, with a capacity to account for varied training. Methods: An in-house proprietary measure (the T2minute method) was developed at the National Rowing Centre of Excellence (NRCE), as a collaborative project between sport scientists and national squad coaches. The design phase was informed by assessments of the existing training measures, and built upon standardised intensity zones established at the Australian Institute of Sport. A common measurement unit was chosen: one T2minute equates to one minute of on-water single scull rowing at T2 intensity (∼60–72% VO2max). Each intensity zone was assigned a weighting factor according to the curvilinear relationship between power output, intensity, and blood lactate response. Each training mode was assigned a weighting factor based on whether coaches perceived it to be “harder” or “easier” than onwater rowing. With coaches’ feedback, the method was refined over a period of five months. The T2minute method was implemented as the core framework for prescribing training for elite Australian rowers throughout the 2009–2012 Olympic cycle. Results: The implementation of the T2minute method successfully established consistency with training prescription and monitoring practices within the NRCE high performance program. The national roll out this method has influenced rowing training methodology at elite and sub-elite levels in Australia. Since implementation, the method has undergone scientific validation. Further research is underway, utilising the method to explore complex relationships between rowers’ training and performance outcomes. Conclusion: The T2minute method is a novel approach that allows rowing coaches and sport scientists to utilise one consistent system to quantify load from varied training. Its implementation represents a considerable achievement in establishing a common framework for managing the training process within a complex organisational structure. This collaborative approach used to develop the T2minute method provides unique insight into the important considerations and practical challenges of applying training science to enhance elite sport performance.

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Purpose: The aim of this study was to determine the effect and reliability of acute and chronic sodium bicarbonate ingestion for 2000-m rowing ergometer performance (watts) and blood bicarbonate concentration [HCO3 -]. Methods: In a crossover study, 7 well-trained rowers performed paired 2000-m rowing ergometer trials under 3 double-blinded conditions: (1) 0.3 grams per kilogram of body mass (g/kg BM) acute bicarbonate; (2) 0.5 g/ kg BM daily chronic bicarbonate for 3 d; and (3) calcium carbonate placebo, in semi-counterbalanced order. For 2000-m performance and [HCO3 -], we examined differences in effects between conditions via pairwise comparisons, with differences interpreted in relation to the likelihood of exceeding smallest worthwhile change thresholds for each variable. We also calculated the within-subject variation (percent typical error). Results: There were only trivial differences in 2000-m performance between placebo (277 ± 60 W), acute bicarbonate (280 ± 65 W) and chronic bicarbonate (282 ± 65 W); however, [HCO3 -] was substantially greater after acute bicarbonate, than with chronic loading and placebo. Typical error for 2000-m mean power was 2.1% (90% confidence interval 1.4 to 4.0%) for acute bicarbonate, 3.6% (2.5 to 7.0%) for chronic bicarbonate, and 1.6% (1.1 to 3.0%) for placebo. Postsupplementation [HCO3 -] typical error was 7.3% (5.0 to 14.5%) for acute bicarbonate, 2.9% (2.0 to 5.7%) for chronic bicarbonate and 6.0% (1.4 to 11.9%) for placebo. Conclusion: Performance in 2000-m rowing ergometer trials may not substantially improve after acute or chronic bicarbonate loading. However, performances will be reliable with both acute and chronic bicarbonate loading protocols. ABSTRACT FROM AUTHOR

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This study examined the effects of 6 mg-kg-1 caffeine ingestion in team-sport players (N.=10) on repeated-sprint running performance (5 sets of 6 x 20 m) and reaction times, 60 min after caffeine or placebo ingestion. Methods. Best single sprint and total set sprint times, blood lactate and simple and choice reaction times (RT) were measured. Total sprint times across sets 1, 3 and 5 (departure every 25 s) were significantly faster after caffeine (85.49±5.55 s) than placebo (86.98±5.78 s) (P<0.05). Similarly, total sprint times across sets 2 and 4 (departure every 60 s), were significantly faster after caffeine (55.99±3.64 s) than placebo (56.77±3.74 s) (P<0.05). Significantly higher blood lactates were recorded in caffeine compared to placebo after set 3 (13.1±1.2 vs 10.3±1.4 mmolL ') (P<0.05) and set 5 (13.1±1.3 vs 103±1.6 mmol-L"1) (P<0.01). There were no significant effects on simple or choice RT, although effect sizes suggested improved post-exercise times after caffeine. Caffeine ingestion 60 min prior to exercise can enhance repeated sprint running performance and is not detrimental to reaction times. [PUBLICATION ABSTRACT]

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Development and implementation of a novel measure for quantifying training loads in rowing: The T2minute method. J Strength Cond Res 28(4): 1172–1180, 2014—The systematic management of training requires accurate training load measurement. However, quantifying the training of elite Australian rowers is challenging because of (a) the multicenter, multistate structure of the national program; (b) the variety of training undertaken; and (c) the limitations of existing methods for quantifying the loads accumulated from varied training formats. Therefore, the purpose of this project was to develop a new measure for quantifying training loads in rowing (the T2minute method). Sport scientists and senior coaches at the National Rowing Center of Excellence collaborated to develop the measure, which incorporates training duration, intensity, and mode to quantify a single index of training load. To account for training at different intensities, the method uses standardized intensity zones (T zones) established at the Australian Institute of Sport. Each zone was assigned a weighting factor according to the curvilinear relationship between power output and blood lactate response. Each training mode was assigned a weighting factor based on whether coaches perceived it to be “harder” or “easier” than on-water rowing. A common measurement unit, the T2minute, was defined to normalize sessions in different modes to a single index of load; one T2minute is equivalent to 1 minute of on-water single scull rowing at T2 intensity (approximately 60–72% V[Combining Dot Above]O2max). The T2minute method was successfully implemented to support national training strategies in Australian high performance rowing. By incorporating duration, intensity, and mode, the T2minute method extends the concepts that underpin current load measures, providing 1 consistent system to quantify loads from varied training formats.

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To investigate the effect of low glycemic index (LGI) carbohydrate meal on subjective, metabolic and physiological responses, and endurance performance in the Ramadan fasted state.

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Aims: We tested whether patrons of the night-time economy who had co-consumed energy drinks or illicit stimulants with alcohol had higher blood alcohol concentration (BAC) levels than patrons who had consumed only alcohol. Design: Street intercept surveys (n=4227) were undertaken between 9 p.m. and 5 a.m. over a period of 7 months. Setting: Interviews were undertaken with patrons walking through entertainment precincts, queuing to enter venues or exiting venues in five Australian cities. Participants: The response rate was 92.1%; more than half the study sample was male (60.2%) and the median age was 23 years (range 18-72). Measurements: Data were collected on demographics, length of drinking session, venue types visited, types and quantity of alcohol consumed and other substance use. A BAC reading was recorded and a subsample of participants was tested for other drug use. Findings: Compared with the total sample (0.068%), illicit stimulant consumers (0.080%; P=0.004) and energy drink consumers (0.074%; P<0.001) had a significantly higher median BAC reading, and were more likely to engage in pre-drinking (65.6, 82.1 and 77.6%, respectively, P<0.001) and longer drinking sessions (4, 5 and 4.5 hours, respectively, P<0.001). However, stimulant use was not associated independently with higher BAC in the final multivariable model (illicit stimulants P=0.198; energy drinks P=0.112). Interaction analyses showed that stimulant users had a higher BAC in the initial stages of the drinking session, but not after 4-6 hours. Conclusions: While stimulant use does not predict BAC in and of itself, stimulants users are more likely to engage in prolonged sessions of heavy alcohol consumption and a range of risk-taking behaviours on a night out, which may explain higher levels of BAC among stimulants users, at least in the initial stages of the drinking session.

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IMPORTANCE: Unhealthy alcohol use is a leading contributor to the global burden of disease, particularly among young people. Systematic reviews suggest efficacy of web-based alcohol screening and brief intervention and call for effectiveness trials in settings where it could be sustainably delivered. OBJECTIVE: To evaluate a national web-based alcohol screening and brief intervention program. DESIGN, SETTING, AND PARTICIPANTS: A multisite, double-blind, parallel-group, individually randomized trial was conducted at 7 New Zealand universities. In April and May of 2010, invitations containing hyperlinks to the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) screening test were e-mailed to 14,991 students aged 17 to 24 years. INTERVENTIONS: Participants who screened positive (AUDIT-C score ≥4) were randomized to undergo screening alone or to 10 minutes of assessment and feedback (including comparisons with medical guidelines and peer norms) on alcohol expenditure, peak blood alcohol concentration, alcohol dependence, and access to help and information. MAIN OUTCOMES AND MEASURES: A fully automated 5-month follow-up assessment was conducted that measured 6 primary outcomes: consumption per typical occasion, drinking frequency, volume of alcohol consumed, an academic problems score, and whether participants exceeded medical guidelines for acute harm (binge drinking) and chronic harm (heavy drinking). A Bonferroni-corrected significance threshold of .0083 was used to account for the 6 comparisons and a sensitivity analysis was used to assess possible attrition bias. RESULTS: Of 5135 students screened, 3422 scored 4 or greater and were randomized, and 83% were followed up. There was a significant effect on 1 of the 6 prespecified outcomes. Relative to control participants, those who received intervention consumed less alcohol per typical drinking occasion (median 4 drinks [interquartile range {IQR}, 2-8] vs 5 drinks [IQR 2-8]; rate ratio [RR], 0.93 [99.17% CI, 0.86-1.00]; P = .005) but not less often (RR, 0.95 [99.17% CI, 0.88-1.03]; P = .08) or less overall (RR, 0.95 [99.17% CI, 0.81-1.10]; P = .33). Academic problem scores were not lower (RR, 0.91 [99.17% CI, 0.76-1.08]; P = .14) and effects on the risks of binge drinking (odds ratio [OR], 0.84 [99.17% CI, 0.67-1.05]; P = .04) and heavy drinking (OR, 0.77 [99.17% CI, 0.56-1.05]; P = .03) were not significantly significant. In a sensitivity analysis accounting for attrition, the effect on alcohol per typical drinking occasion was no longer statistically significant. CONCLUSIONS AND RELEVANCE: A national web-based alcohol screening and brief intervention program produced no significant reductions in the frequency or overall volume of drinking or academic problems. There remains a possibility of a small reduction in the amount of alcohol consumed per typical drinking occasion. TRIAL REGISTRATION: anzctr.org.au Identifier: ACTRN12610000279022.

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INTRODUCTION AND AIMS: Understanding how types of alcohol consumers differ is important for public policy targeted at reducing adverse events. The aims of the present study were to identify typologies of alcohol consumers in Australian nighttime entertainment districts based on risk factors for harm and to examine variation between the identified groups in drinking setting and harms. DESIGN AND METHODS: Street-intercept surveys were conducted with 5556 alcohol consumers in and around licensed venues in five Australian cities between November 2011 and June 2012. Latent class analysis identified groups based on age and sex, and blood alcohol concentration, pre-drinking, energy drink use and illicit drug use during that night. RESULTS: Four classes were identified: general patron group (33%), young pre-drinker group (27%), intoxicated male pre-drinker group (31%) and intoxicated illicit drug male group (9%). The proportion of the general patron group interviewed decreased over the night, while the other groups increased (particularly in regional cities). As compared with the general patron group, the remaining three groups reported increased odds of being involved in aggression and any alcohol-related injuries in the past 3 months, with highest rates of harm amongst the intoxicated illicit drug male group. DISCUSSION AND CONCLUSIONS: Alcohol consumers in nighttime entertainment districts are not a homogeneous group. One-third have a low likelihood of risky consumption practices; however, representation of this consumer class diminishes throughout the night. Elevated harms amongst groups characterised by certain risk factors (e.g. pre-drinking and illicit drug use) emphasise the importance of addressing these behaviours in public policy.

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Objetivo: estudar os efeitos hemodinâmicos da solução salina hipertônica/dextran, comparada com solução salina normal, em pacientes com sepse grave. Modelo: ensaio clínico randomizado, prospectivo, duplo-cego, controlado. Local: Unidade de Terapia Intensiva de um hospital universitário. Pacientes: 29 pacientes com sepse grave, admitidos na UTI com pressão de oclusão da artéria pulmonar (POAP) menor que 12 mmHg. Intervenções: os pacientes foram randomizados para receber 250 ml da solução salina normal [NaCl 0,9%] (Grupo SS, n=16) ou solução salina hipertônica [NaCl 7,5%]/dextran 70 8% ( Grupo SSH, n=13). Medidas e resultados: para cada grupo foram coletadas medidas hemodinâmicas, gasometrias (arterial e venosa), lactato e sódio séricos nos tempos 0, 30 minutos, 60 minutos, 120 minutos e 180 minutos. Durante o período do estudo não foi permitida qualquer alteração na infusão tanto de fluidos quanto das drogas vasopressoras. A POAP foi maior no grupo SSH, com a diferença sendo maior em 30 minutos (10,7±3,2 mmHg vs. 6,8±3,2 mmHg) e 60 minutos (10,3±3 mmHg vs. 7,4±2,9 mmHg); p<0,05. O índice cardíaco aumentou apenas no grupo SSH, sendo que as diferenças foram maiores em 30 minutos (6,5±4,7 l min-1 m-2 vs. 3,8±3,4 l min-1 m-2), em 60 minutos (4,9±4,5 l min-1 m-2 vs. 3,7±3,3 l min-1 m-2) e em 120 minutos (5,0±4,3 l min-1 m-2 vs. 4,1±3,4 l min-1 m-2); p<0,05. O índice sistólico seguiu o mesmo padrão e foi maior em 30 minutos (53,6[39,2-62,8] ml m-2 vs. 35,6[31,2-49,2] ml m-2) e em 60 minutos (46,8[39,7-56,6] ml m-2 vs. 33,9[32,2-47,7] ml m-2); p<0,05. A resistência vascular sistêmica diminuiu no grupo SSH e foi menor nos tempos 30 minutos (824±277 dyne s-1 cm-5 m-2 vs. 1139±245 dyne s-1 cm-5 m-2), em 60 minutos (921±256 dyne s-1 cm-5 m-2 vs. 1246±308 dyne s-1 cm-5 m-2) e em 120 minutos (925±226 dyne s-1 cm-5 m-2 vs. 1269±494 dyne s-1 cm-5 m-2); p<0,05. O sódio sérico aumentou no grupo SSH e foi maior do que o grupo SS em 30 minutos (145±3 mEq l-1 vs. 137±7 mEq l-1), em 60 minutos (143±4 mEq l-1 vs. 136±77 mEq l-1), em 120 minutos (142±5 mEq l-1vs. 136±7 mEq l-1) e em 180 minutos (142±5 mEq l-1 vs. 136±87 mEq l-1); p<0,05. Conclusão: Solução salina hipertônica/dextran pode melhorar a performance cardiovascular na ressuscitação de pacientes com sepse grave. Os efeitos hemodinâmicos parecem estar relacionados tanto ao efeito no volume quanto a melhora da função cardíaca. A SSH/dextran podem ajudar a restaurar rapidamente a estabilidade hemodinâmica em pacientes sépticos, hipovolêmicos, sem apresentar efeitos indesejáveis significativos.

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Alcohol is one of the few psychotropic drugs that their consumption has admitted legally and sometimes encouraged by the society. Studies show alcohol as the highest consumption of drugs among young people and society in general, probably because of its availability and easy access. The abuse causes public health problems, which was closely related to the violence, socioeconomic problems and the high number of automobile accidents. Transit is one of the main sectors affected by the effects of alcohol, observing a high incidence in the studies. About half of automobile accidents occurs after the consumption of alcoholic beverage, and the vast majority of cases related to high concentrations of alcohol in the bloodstream. The relationship of drunk with traffic accidents is in fact evident everywhere in the world, including Brazil, where studies have shown a high relationship between alcohol consumption and traffic accidents. This study determined the alcohol in fatal victims of traffic accidents in the state of Rio Grande do Norte and established the profile of this population compared with those found in Brazil and other countries. Samples of blood of ethanol added to fulfillment of the standardization of chromatographic conditions and procedures for the analysis, being employed in the determination of alcohol in blood samples of 277 victims of traffic accidents, collected at the Institute of Scientific Technical Police of Rio Grande do North (ITEP) in the year 2007. The blood alcohol level was determined in these samples correlated with the sex, age and marital status of the victim and the location, day of week and month when the accident occurred, is doing a statistical analysis and outlining a profile of the victims of an accident at transit in the state of Rio Grande do Norte. The parameters of standardization studied ensured the quality of the analytical method and, consequently, to obtain reliable laboratory results. Being given the best temperature for injector (150 ºC), detector (250 ºC) and column (50 ºC) with a flow of gas in the column of 2mL/minutos and analysis of time of 12 minutes. The method was linear in the range of 0.01 to 3.2 g / L (r2 = 0.9989) with average recovery of 100.2% and precision with coefficient of variation less than 15%. The analysis carried out on victims of fatal road traffic accidents, ethanol detected in the blood in 66.43% of the victims and these, 96% showed concentration ≥ 0.2 g / L, 87.73% of victims were male, while 12.27% female. The younger age group (1535 years) was the most involved (52,35%) and most single (55.60%). The accidents occurred with greater prevalence in the day on Monday (27%) followed by Sunday (24,19%) and Saturday (15,52%) and it was found that the prevalence of injuries varied between the different months of the year, and in February (14.4%) and April (10.47%) the months that had a higher number of accidents, however this oscillation showed no statistically significant difference. Also no significant difference was observed between the tracks of concentration found in men and women. The standardized method showed to be efficient, given satisfactorily to the goals of this work, and the high levels of alcohol found in victims of fatal road traffic accidents are consistent with several studies of literature, and the profile of the victim also supported by presenting in its most young adults, male and single

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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As efusões são problemas clínicos frequentes e que ocorrem em consequência de uma enfermidade que culmine com diminuição da pressão coloidosmótica intravascular, elevação da pressão hidrostática local, aumento da permeabilidade vascular e/ou comprometimento da drenagem realizada pelos vasos linfáticos. Dessa maneira, a avaliação laboratorial desse fluido torna-se relevante para que, em conjunto com os sinais clínicos apresentados pelo paciente, possa ser firmado um possível diagnóstico e instituída ação terapêutica adequada. Assim sendo, a classificação de uma efusão em transudato ou exsudato torna-se um dos pontos críticos para a elucidação do diagnóstico e condução do caso clínico. em Medicina Veterinária, o método tradicional de classificação de uma efusão é baseado na contagem celular e na concentração de proteínas do fluido. Contudo, diversos estudos evidenciam que tais parâmetros não são suficientes para a correta classificação de todas as efusões. Assim, o presente estudo foi conduzido com o objetivo de verificar a correlação de outros parâmetros bioquímicos com a diferenciação das efusões transudativas e exsudativas e, para tal, foram avaliadas as atividades de lacatato desidrogenase (LDH) das efusões, a relação de sua atividade fluido/soro, concentração de lactato das efusões, o gradiente de concentração de lactato do soro para o fluido e a concentração de proteínas das efusões. Os resultados obtidos permitiram observar que a atividade de LDH, a relação LDH efusão/soro, a concentração de lactato e o gradiente de concentração de lactato soro/efusão apresentam diferença estatisticamente significativa (P<0,05), bem como alta correlação com a classificação de uma efusão exsudativa.

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Objetivou-se avaliar em equino a influência do exercício progressivo e intenso realizado em esteira de alta velocidade sobre a temperatura de regiões da pele, incluindo face, pescoço e quartela, e do casco, incluindo coroa, parede e sola. Utilizaram-se cinco equinos Puro Sangue Árabes, desferrados, com idade média de 8±0,7 anos, sendo duas fêmeas e três machos, com peso corpóreo médio de 420±10kg. A intensidade de esforço foi determinada por meio da quantificação do lactato sanguíneo. As temperaturas foram determinadas com o auxílio de termógrafo, antes, durante e após o exercício. Realizou-se análise de variância seguida pelo teste de Tukey, sendo P≤0,05. A lactacidemia aumentou, principalmente nas velocidades intensas. Houve redução das temperaturas das regiões da face, pescoço e quartela após o exercício e diminuição das temperaturas da parede, coroa e sola do casco durante o exercício, enquanto a temperatura da manta de rolamento da esteira não se alterou em nenhum momento. Constatou-se indiretamente que a perfusão sanguínea do casco diminuiu durante o teste de esforço tanto em sua fase aeróbia como na anaeróbia. Nenhuma das intensidades de esforço foi capaz de alterar a temperatura da manta de rolamento da esteira. A temperatura do casco diminuída como decorrência fisiológica do esforço físico imposto, retornou aos valores normais após o término do exercício.

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The objective of this study was to evaluate the effect of low laser power on the performance of anaerobic endurance of the quadriceps muscle in young subjects. Low-level laser therapy (LLLT) appears to decrease some indices of muscle fatigue. Most of these effects may be due to the influence of the laser on the muscles predominantly aerobic. Animal studies and clinical trials have already shown that the laser can improve the efficiency of mitochondrial metabolism for the resynthesis of adenosine triphosphate and thus slow down - or minimize, the deleterious effects of muscle fatigue. This research was characterized as an experimental study of the controlled clinical trial, randomized, blinded, attended by 93 volunteers, military, with ages between 18 and 19 years. The subjects were randomly allocated into three groups: Control (G1), Placebo (G2) and Laser (G3). All volunteers underwent an anthropometric assessment and a protocol Fatigue. This protocol was applied to an initial assessment (AV-1) for the collection of baseline data, and a final evaluation (AV-2). As the study variables, we used the blood lactate concentrations and indices of muscle power, as average power and peak velocity. The fatigue protocol consisted of a test of speed with twenty repetitions, performed on an exercise machine leg press 45º . In conclusion, it was found that, in this study, LLLT caused a significant increase in the Average of the Averages Powers, phase eccentric exercise in leg press 45º performed by young individuals