36 resultados para CYCLING TIME-TRIAL
em University of Queensland eSpace - Australia
Resumo:
Purpose: The impact of acute weight loss on rowing performance was assessed when generous nutrient intake was provided in 2 h of recovery after making weight. Methods: Competitive rowers (N = 17) completed four ergometer trials, each separated by 48 h. Two trials were performed after a 4% body mass loss in the previous 24 h (WT) and two were performed after no weight restrictions, that is, unrestricted (UNR). In addition, two trials (I X WT, I X UNR) were in a thermoneutral environment (NEUTRAL, mean 21.1 +/- SD 0.7 degrees C, 29.0 +/- 4.5% RH) and two were in the heat (HOT 32.4, +/- 0.4 degrees C, 60.4 +/- 2.7% RH). Trials were performed in a counterbalanced fashion according to a Latin square design. Aggressive nutritional recovery strategies (WT 2.3 g(.)kg(-11) carbohydrate, 34 mg-kg(-1) Na, 28.4 mL(.)kg(-1) fluid; UNR ad libitum) were employed in the 2 h after weigh-in. Results: Both WT (mean 2.1, 95% CI 0.7-3.4 s; P = 0.003) and HOT (4.1, 2.7 - 5.4 s; P < 0.001) compromised 2000-m time-trial performance. Whereas WT resulted in hypohydration, the associated reduction in plasma volume explained only part of the performance compromise observed (0.2 s for every 1% decrement) Moreover, WT did not influence core temperature or indices of cardiovascular function. Conclusions: Acute weight loss compromised performance, despite generous nutrient intake in recovery, although the effect was small. Performance decrements were further exacerbated when exercise was performed in the heat.
The influence of bovine colostrum supplementation on exercise performance in highly trained cyclists
Resumo:
Purpose: The aim of this experiment was to investigate the influence of low dose bovine colostrum supplementation on exercise performance in cyclists over a 10 week period that included 5 days of high intensity training (HIT). Methods: Over 7 days of preliminary testing, 29 highly trained male road cyclists completed a VO2max test (in which their ventilatory threshold was estimated), a time to fatigue test at 110% of ventilatory threshold, and a 40 km time trial (TT40). Cyclists were then assigned to either a supplement (n = 14, 10 g/day bovine colostrum protein concentrate (CPC)) or a placebo group (n = 15, 10 g/day whey protein) and resumed their normal training. Following 5 weeks of supplementation, the cyclists returned to the laboratory to complete a second series of performance testing (week 7). They then underwent five consecutive days of HIT (week 8) followed by a further series of performance tests (week 9). Results: The influence of bovine CPC on TT40 performance during normal training was unclear (week 7: 1+/-3.1%, week 9: 0.1+/-2.1%; mean+/-90% confidence limits). However, at the end of the HIT period, bovine CPC supplementation, compared to the placebo, elicited a 1.9+/-2.2% improvement from baseline in TT40 performance and a 2.3+/-6.0% increase in time trial intensity (% VO2max), and maintained TT40 heart rate (2.5+/-3.7%). In addition, bovine CPC supplementation prevented a decrease in ventilatory threshold following the HIT period (4.6+/-4.6%). Conclusion: Low dose bovine CPC supplementation elicited improvements in TT40 performance during an HIT period and maintained ventilatory threshold following five consecutive days of HIT.
Resumo:
We derive observed H alpha and R-band luminosity densities of an H I-selected sample of nearby galaxies using the SINGG sample to be l'(H alpha) = (9.4 +/- 1.8) x 10(38) h(70) ergs s(-1) Mpc(-3) for H alpha and l'(R) = (4.4 +/- 9.7) x 10(37) h(70) ergs s(-1) angstrom(-1) Mpc(-3) in the R band. This R-band luminosity density is approximately 70% of that found by the Sloan Digital Sky Survey. This leads to a local star formation rate density of log ((rho)over dot(SFR) [M-circle dot yr(-1) Mpc(-3)]) = -1.80(-0.07)(+0.13)(random) +/- 0.03(systematic) + log (h(70)) after applying a mean internal extinction correction of 0.82 mag. The gas cycling time of this sample is found to be t(gas) = 7.5(-2.1)(+1.3) Gyr, and the volume-averaged equivalent width of the SINGG galaxies is EW(H alpha) = 28.8(-4.7)(+7.2) angstrom (21.2-3.5+4.2 angstrom without internal dust correction). As with similar surveys, these results imply that (rho)over dot(SFR)(z) decreases drastically from z similar to 1.5 to the present. A comparison of the dynamical masses of the SINGG galaxies evaluated at their optical limits with their stellar and H I masses shows significant evidence of downsizing: the most massive galaxies have a larger fraction of their mass locked up in stars compared with H I, while the opposite is true for less massive galaxies. We show that the application of the Kennicutt star formation law to a galaxy having the median orbital time at the optical limit of this sample results in a star formation rate decay with cosmic time similar to that given by the. (rho)over dot(SFR)(z) evolution. This implies that the (rho)over dot(SFR)(z) evolution is primarily due to the secular evolution of galaxies, rather than interactions or mergers. This is consistent with the morphologies predominantly seen in the SINGG sample.
Resumo:
Objectives: To assess the influence of moderate, acute weight loss on on-water rowing performance when aggressive nutritional recovery strategies were used in the two hours between weigh in and racing. Methods: Competitive rowers (n=17) undertook three on-water 1800 m time trials under cool conditions ( mean (SD) temperature 8.4 (2.0)degrees C), each separated by 48 hours. No weight limit was imposed for the first time trial-that is, unrestricted body mass (UNR1). However, one of the remaining two trials followed a 4% loss in body mass in the previous 24 hours (WT-4%). No weight limit was imposed for the other trial (UNR2). Aggressive nutritional recovery strategies (WT-4%, 2.3 g/kg carbohydrate, 34 mg/kg Na+, and 28.4 ml/kg fluid; UNR, ad libitum) were used in the first 90 minutes of the two hours between weigh in and performance trials. Results: WT-4% had only a small and statistically non-significant effect on the on-water time trial performance ( mean 1.0 second, 95% confidence interval (CI) 20.9 to 2.8; p=0.29) compared with UNR. This was despite a significant decrease in plasma volume at the time of weigh in for WT-4% compared with UNR (-9.2%, 95% CI -12.8% to -5.6%; p
Resumo:
Background The treatment of infants with bronchiolitis is largely supportive. The role of bronchodilators is controversial. Most studies of the use of bronchodilators have enrolled small numbers of subjects and have examined only short-term outcomes, such as clinical scores. Methods We conducted a randomized, double-blind, controlled trial comparing nebulized single-isomer epinephrine with placebo in 194 infants admitted to four hospitals in Queens-land, Australia, with a clinical diagnosis of bronchiolitis. Three 4-ml doses of 1 percent nebulized epinephrine or three 4-ml doses of normal saline were administered at four-hour intervals after hospital admission. Observations were made at admission and just before, 30 minutes after, and 60 minutes after each dose. The primary outcome measures were the length of the hospital stay and the time until the infant was ready for discharge. The secondary outcome measures were the degree of change in the respiratory rate, the heart rate, and the respiratory-effort score and the time that supplemental oxygen was required. Results There were no significant overall differences between the groups in the length of the hospital stay (P=0.16) or the time until the infant was ready for discharge (P=0.86). Among infants who required supplemental oxygen and intravenous fluids, the time until the infant was ready for discharge was significantly longer in the epinephrine group than in the placebo group (P=0.02). The need for supplemental oxygen at admission had the greatest influence on the score for severity of illness and strongly predicted the length of the hospital stay and the time until the infant was ready for discharge (P
Resumo:
Background and purpose: Trans-Tasman Radiation Oncology Group 96.05 is a prospective randomized controlled trial comparing a single 8 Gy with 20 Gy in five fractions of radiotherapy (RT) for neuropathic pain due to bone metastases. This paper summarizes the quality assurance (QA) activities for the first 234 patients (accrual target 270). Materials and methods: Independent audits to assess compliance with eligibility/exclusion criteria and appropriateness of treatment of the index site were conducted after each cohort of approximately 45 consecutive patients. Reported serious adverse events (SAEs) in the form of cord/cauda equina compression or pathological fracture developing at the index site were investigated and presented in batches to the Independent Data Monitoring Committee. Finally, source data verification of the RT prescription page and treatment records was undertaken for each of the first 234 patients to assess compliance with the protocol. Results: Only one patient was found conclusively not to have genuine neuropathic pain, and there were no detected 'geographical misses' with RT fields. The overall rate of detected infringements for other eligibility criteria over five audits (225 patients) was 8% with a dramatic improvement after the first audit. There has at no stage been a statistically significant difference in SAEs by randomization arm. There was a 22% rate of RT protocol variations involving ten of the 14 contributing centres, although the rate of major dose violations (more than +/- 10% from protocol dose) was only 6% with no statistically significant difference by randomization arm (P = 0.44). Conclusions: QA auditing is an essential but time-consuming component of RT trials, including those assessing palliative endpoints. Our experience confirms that all aspects should commence soon after study activation. Crown Copyright (C) 2003 Published by Elsevier Science Ltd. All rights reserved.
Resumo:
The purpose of this study was to prospectively examine the effectiveness and tolerability of a simple radiotherapy technique for the palliation of symptomatic liver metastases. Twenty-eight patients with symptomatic liver metastases were enrolled from seven centres, and received targeted (partial or whole) liver irradiation consisting of 10 Gy in two fractions over 2 days. Symptoms at baseline were hepatic pain (27 patients), abdominal distension (19), night sweats (12), nausea (18) and vomiting (eight). Twenty-two patients (76%) had failed previous treatment with chemotherapy, hormonal therapy and/or high-dose steroids. Symptoms and potential toxicities were prospectively assessed at the time of treatment, then 2, 6 and 10 weeks later. Individual symptom response rates were 53−66% at 2 weeks. Partial or complete global symptomatic responses were noted in 15 patients (54%) overall. The treatment was well tolerated with two patients (7%) experiencing grade 3 toxicity (one vomiting and one diarrhoea); however, four patients reported temporary worsening of pain shortly after treatment. This simple and well-tolerated treatment achieves useful palliation.
Resumo:
Objective: To compare the effectiveness of three dosing regimens of caffeine for preterm infants in the periextubation period. Methods: A randomized double-blind clinical trial of three dosing regimens of caffeine citrate ( 3, 15 and 30 mg/kg) for periextubation management of ventilated preterm infants was undertaken. Infants born < 32 weeks gestation who were ventilated for > 48 h were eligible for the study. Caffeine citrate was given as a once daily dose for a period of 6 days commencing 24 h prior to a planned extubation, or within 6 h of an unplanned extubation. The primary outcome measure was extubation failure, defined as neonates who were unable to be extubated within 48 h of caffeine loading or who required reventilation or doxapram dose within 7 days of caffeine loading. Continuous recordings of oxygen saturation and heart rate were undertaken in a subgroup of enrolled infants. Results: A total of 127 babies were enrolled into the study ( 42, 40, 45, in the 3, 15, and 30 mg/kg groups, respectively). No statistically significant difference was demonstrated in the incidence of extubation failure between dosing groups ( 19, 10, and 11 infants in the 3, 15, and 30 mg/kg groups, respectively), however, infants in the two higher dose groups had statistically significantly less documented apnoea than the lowest dose group. Of the 37 neonates with continuous pulse oximetry recordings, those on higher doses of caffeine recorded a statistically significantly higher mean heart rate, oxygen saturations and less time with oxygen saturations < 85%. Conclusions: This trial indicated there were short-term benefits of decreased apnoea in the immediate periextubation period for ventilated infants born < 32 weeks gestation receiving higher doses of caffeine. Further studies with larger numbers of infants assessing longer-term outcomes are necessary to determine the optimal dosing regimen of caffeine in preterm infants.
Resumo:
Background: Solar keratoses (SKs) are among the strongest determinants of skin cancer, but little is known about the success of measures to control these common skin tumors. Objective: To determine whether daily sunscreen application and/or beta carotene supplementation retards the rate of occurrence of SKs in adults in the medium term. Design: Randomized controlled trial conducted between February 1992 and August 1996. Setting: General community of the subtropical township of Nambour, Australia (latitude, 26degrees south). Participants: A total of 1621 adults aged 25 to 74 years. Interventions: Participants were randomized to daily use of sunscreen (application of a high-protection sunscreen to their head, neck, arms, and hands every morning) or application of sunscreen at their usual discretionary rate. They were also randomly assigned to take either one 30-mg tablet of beta carotene or one placebo tablet each day. Main Outcome Measure: Change in the prevalent number of SKs in the intervention group relative to change in the control group. Results: The ratio of SK counts in 1994 relative to 1992 was lower in people randomized to daily sunscreen use (1.20; 95% confidence interval, 1.04-1.39) than in those randomized to discretionary sunscreen use (1.57; 95% confidence interval, 1.35-1.84). This 24% reduction is equivalent to the prevention of an average of I additional SK per person over that time. A reduction in the rate of change of SK prevalence was also seen in the sunscreen intervention group relative to the discretionary sunscreen group between 1994 and 1996, but it was not significant. No effect on the rate of change of prevalent SK counts was seen among those taking beta carotene supplements relative. to those taking placebo tablets. Conclusions: Daily application of sunscreen retarded the rate of SK acquisition among adults in a subtropical environment, while a beta carotene supplementation of 30 mg/d had no influence on the occurrence of SKs.
Resumo:
Background. Both self-help print materials and telephone-assisted counseling have generally proved useful strategies to increase physical activity. This study examined their effectiveness in an intervention aimed specifically at promoting walking for specific purposes. Methods. Participants (n = 399) were randomly allocated to one of two 3-week intervention programs. The Print program comprised multiple mailing of brochures that emphasized walking within the local community environments. The Print plus Telephone program received the same brochures plus three telephone calls. Data collected via mailed self-completed surveys were analyzed by exploring outcomes related to walking for specific purposes. Results. There were no significant differences between the two programs in any of the walking measures. Both groups significantly increased time reported walking for exercise per week [Print: t(1,277) = -3.50, P < 0.001; Print plus telephone: t(1,106) = -2.44, P < 0.016]. Significantly, more participants in the Print plus Telephone group reported receiving and reading the materials (chi(2) = 20.11, P < 0.0001). Conclusions. The intervention programs were more successful at increasing walking for exercise than for any other purpose. The addition of brief telephone support was successful in focusing participants' attention on the print materials, but did not result in any additional increase in walking. (C) 2004 The Institute For Cancer Prevention and Elsevier Inc. All rights reserved.
Resumo:
Purpose: To evaluate the efficacy of hyperbaric oxygen therapy in the treatment of alkali-induced corneal burns in an animal model. Methods: Twenty-four rabbits were randomized into a control group (n = 12) and hyperbaric oxygen treatment group (n = 12). After induction of anaesthesia, the alkali burn model was established by application of 1 N sodium hydroxide to one eye of each rabbit. The hyperbaric oxygen treatment group was treated each day for 21 days with hyperbaric oxygen at 2.4 Atmospheres Absolute (ATA) for 1 h. The eyes of the animals were examined daily for 2 weeks and then weekly until the end of the trial. The principal endpoint was that of perforation of the cornea at which time the animals were killed with a lethal dose of either intravenous or intraperitoneal barbiturate and the eyes immediately enucleated and fixed in 10% neutral buffered formalin. All animals in which complete healing took placed were also killed, the eyes removed, fixed and examined histologically. Photographs were taken of the rabbit's eyes at weekly intervals and the area of vascularization and epithelial defects in the hyperbaric and control groups were compared. Results: Equal numbers (seven) of the control and hyperbaric oxygen treated groups had perforated corneas and there was no statistical difference in the mean time to perforation (control 30.1 days; treated 30 days). There was also no statistical difference between the two groups with respect to epithelial defect size. Conclusion: Treatment with hyperbaric oxygen for 1 h daily for 21 days had no beneficial effect on alkali-induced corneal burns.
Resumo:
Background. Although smoking cessation programs significantly reduce smoking rates in the general population, some sectors are poorly motivated by them, especially healthy men from lower socioeconomic classes. Methods. By using a significant life event (approaching birth of a child) we exploited a time of increased receptiveness to smoking cessation influences. A multicomponent intervention was conducted and evaluated using a stratified, randomised control trial, with an intention to treat analysis. Results. Five hundred and sixty-one men were enrolled and 505 (90%) followed to the end of their partners' pregnancy. At 6-month follow-up 16.5% of 291 smokers of the intervention group and 9.3% of 270 in the control group reported they had stopped smoking (P = 0.011, OR = 0.52, 95% CI 0.31 - 0.86). The strongest predictors of smoking cessation were being in a skilled occupation, having a higher number of quit attempts in the previous year and having the first cigarette of the day relatively later. Conclusions. The number of smoking men who had to be treated to achieve one stopping smoking (NNT) during their partner's pregnancy was 13 to 14. Innovative antismoking population health measures for the partners of antenatal patients are effective and perhaps should be more widely adopted. (C) 2003 American Health Foundation and Elsevier Inc. All rights reserved.
Resumo:
To investigate the effects of different management strategies for non-localized prostate cancer on men's quality of life and cognitive functioning. Men with prostate cancer were randomly assigned to one of four treatment arms: leuprorelin, goserelin, cyproterone acetate (CPA), or close clinical monitoring. In a repeated-measures design, men were assessed before treatment (baseline) and after 6 and 12 months of treatment. A community comparison group of men of the same age with no prostate cancer participated for the same length of time. The men were recruited from public and private urology departments from university teaching hospitals. All those with prostate cancer who were eligible for hormonal therapy had no symptoms requiring immediate therapy. In all, 82 patients were randomized and 62 completed the 1-year study, and of the 20 community participants, 15 completed the study. The main outcome measures were obtained from questionnaires on emotional distress, existential satisfaction, physical function and symptoms, social and role function, subjective cognitive function, and sexual function, combined with standard neuropsychological tests of memory, attention, and executive functions. Sexual dysfunction increased for patients on androgen-suppressing therapies, and emotional distress increased in those assigned to CPA or close clinical monitoring. Compared with before treatment there was evidence of an adverse effect of leuprorelin, goserelin, and CPA on cognitive function. In deciding the timing of androgen suppression therapy for prostate cancer, consideration should be given to potential adverse effects on quality of life and cognitive function.