RESUMO
This study examined the association between monitoring tools, training loads, and performance in concurrent heat and hypoxia (H + H) compared with temperate training environments. A randomized parallel matched-group design involved 18 well-trained male cyclists. Participants performed 12 interval sessions (3 weeks) in either H + H (32 ± 1 °C, 50% RH, 16.6% O2 normobaric hypoxia) or control (21 °C, 50% RH, 21% O2 ), followed by a seven-session taper (3 weeks; 21 °C, 50% RH, 21% O2 ), while also maintaining external training (â¼ 6-10 h/week). A 20-km time trial (TT) was completed pre- and post-training block (21 °C, 50% RH, 21% O2 ). Before each TT and once weekly, a 4-min cycle warm-up (70% 4-min mean maximum power) was completed. Visual analog scale rating for pain, recovery, and fatigue was recorded before the warm-up, with heart rate (HREx ), heart rate recovery (HRR), and rating of perceived exertion (RPEWU ) recorded following. Training load was quantified using the session rating of perceived exertion (sRPE) method throughout. Overall TT improved 35 ± 47 s with moderate correlations to HRR (r = 0.49) and recovery (r = -0.55). H + H group had a likely greater reduction in HREx [ES = -0.50 (90% CL) (-0.88; 0.12)] throughout and a greater sRPE (ES = 1.20 [0.41; 1.99]), and reduction in HRR [ES = -0.37 (-0.70;-0.04)] through the overload. RPEWU was associated with weekly training load (r = 0.37). These findings suggest that recovery and HRR in a temperate environment may be used as simple measures to identify an athlete's readiness to perform. Alternatively, the relationship of RPEWU and training load suggests that perception of effort following a standardized warm-up may be a valid measure when monitoring an athlete's training response, irrespective of the training environment.
Assuntos
Ciclismo/fisiologia , Fadiga/fisiopatologia , Frequência Cardíaca/fisiologia , Temperatura Alta/efeitos adversos , Hipóxia/fisiopatologia , Esforço Físico/fisiologia , Aptidão Física/fisiologia , Adulto , Teste de Esforço , Fadiga/etiologia , Humanos , Masculino , Monitorização Fisiológica/métodos , Método Simples-CegoRESUMO
PURPOSE: To assess the validity of methods for quantifying training load, fitness and fatigue in endurance athletes using a mathematical model. METHODS: Seven trained runners (VO2max: 51.7 ± 4.5 mL kg(-1) min(-1), age: 38.6 ± 9.4 years, mean ± SD) completed 15 weeks of endurance running training. Training sessions were assessed using a heart rate (HR), running pace and rating of perceived exertion (RPE). Training dose was calculated using the session-RPE method, Banisters TRIMP and the running training stress score (rTSS). Weekly running performance (1,500-m time trial), fitness (submaximal HR, resting HR) and fatigue [profile of mood states, heart rate variability (HRV)] were measured. A mathematical model was applied to the training data from each runner to provide individual estimates of performance, fitness and fatigue. Correlations assessed the relationships between the modelled and actual weekly performance, fitness and fatigue measures within each runner. RESULTS: Training resulted in 5.4 ± 2.6 % improvement in 1,500-m performance. Modelled performance was correlated with actual performance in each subject, with relationships being r = 0.70 ± 0.11, 0.60 ± 0.10 and 0.65 ± 0.13 for the rTSS, session-RPE and TRIMP input methods, respectively. There were moderate correlations between modelled and actual fitness (submaximal HR) for the session-RPE (-0.43 ± 0.37) and TRIMP (-0.48 ± 0.39) methods and moderate-to-large correlations between modelled and actual fatigue measured through HRV indices for both session-RPE (-0.48 ± 0.39) and TRIMP (-0.59 ± 0.31) methods. CONCLUSIONS: These findings showed that each of the training load methods investigated are appropriate for quantifying endurance training dose and that submaximal HR and HRV may be useful for monitoring fitness and fatigue, respectively.
Assuntos
Teste de Esforço/métodos , Tolerância ao Exercício , Modelos Biológicos , Adulto , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Fadiga Muscular , Esforço Físico , Corrida/fisiologiaRESUMO
AIM: Athletes should match their energy intake with expenditure in order to maintain lean body mass. It is also important to consume adequate amounts of antioxidant vitamins and minerals to maintain health. METHODS: To assess the dietary habits of six nationally ranked Australian swimmers physical training load and dietary intake (24 h food recall) and were recorded on a daily basis during a 4 day intensive physical training period. RESULTS: The results showed no significant difference between energy intake and expenditure (P=0.58) or the amount of carbohydrate consumed (P=0.14) compared to the Australian recommended daily intake (RDI). Athletes reported a significantly greater intake of vitamin A (P<0.01), vitamin C (P<0.01), vitamin E (P<0.01) and protein (P<0.01) than the RDI. CONCLUSION: It was concluded that these elite swimmers have an adequate dietary intake to allow for optimal physical training and performance.
Assuntos
Antioxidantes/administração & dosagem , Atletas , Comportamento Alimentar , Estado Nutricional , Educação Física e Treinamento , Natação/fisiologia , Composição Corporal , Suplementos Nutricionais , Ingestão de Energia , Metabolismo Energético , Humanos , Masculino , Estatísticas não Paramétricas , Adulto JovemRESUMO
The present investigation compared responses in previously identified physiological, biochemical, and psychological markers of overreaching in triathletes. Sixteen experienced male triathletes (.VO(2max) [mean +/- SD] = 55.7 +/- 4.9 mL . kg (-1) . min (-1), age = 31.3 +/- 11.7 yr) were divided into matched groups according to physical and performance characteristics, and were randomly assigned to either intensified training (IT) or normal training (NT) groups. Physiological, biochemical, and psychological measures were taken at baseline, following four weeks of overload training and following a two-week taper. The IT group completed 290 % greater physical training load than the NT group during the overload period. The subjects completed a 3-km run time trial (3-km RTT) each week in order to assess the time course of change in endurance performance. 3-km RTT performance was significantly reduced (3.7 +/- 7.5 %; p < 0.05) following four weeks of overload training in the IT group confirming a state of overreaching. During the same period, 3-km RTT performance significantly improved in the NT group (3.0 +/- 1.1 %; p < 0.05). Following the two-week taper, 3-km RTT performance significantly improved in the IT group (7.0 +/- 5.6 %; p < 0.05). Hemoglobin concentration significantly decreased and urea increased in both groups during the overload period (p < 0.05). During the taper hemoglobin normalized with a greater increase in the IT group compared to the NT group (p < 0.05). A significant increase in free testosterone to cortisol ratio was also observed in the IT group compared to the NT group during the taper (p < 0.05). No significant changes were observed for any other biochemical variables during the period of investigation. The RESTQ-76 Sport questionnaire showed an impaired recovery-stress state with increased training load, which improved following the taper in the IT group (p < 0.05). These present results suggest that none of the physiological and biochemical variables measured in this study were effective for the early identification of overreaching in experienced triathletes. However, the RESTQ-76 Sport questionnaire may provide a practical tool for recognizing overreaching in its early stages. These findings have implications for monitoring training status in athletes in a practical training setting.
Assuntos
Educação Física e Treinamento/métodos , Esforço Físico/fisiologia , Recuperação de Função Fisiológica/fisiologia , Esportes/fisiologia , Estresse Psicológico/fisiopatologia , Adulto , Hemoglobinas/análise , Humanos , Hidrocortisona/sangue , Masculino , Neutrófilos/metabolismo , Inquéritos e Questionários , Testosterona/sangue , Ureia/sangueRESUMO
Steel factor (SF) synergizes with a variety of hemopoietins to support the growth and differentiation of human progenitor cells. The human factor-dependent cell line MO7 has been used as a model to study the interaction of SF with other growth factors such as GM-CSF, because both factors support the proliferation of this cell line and are synergistic in combination. Previous studies have shown that this effect is not readily explained by the synergistic activation of early, cytosolic signal transduction intermediates such as tyrosine kinases, Raf-1, MAP2 kinase, or phospholipase C gamma. In an attempt to further explore the biological and biochemical mechanisms of the synergy between SF and GM-CSF, we examined the effects of these growth factors on the regulation of nuclear proto-oncogenes, cell cycle control genes, and G1-->S transition of MO7 cells. Individually, GM-CSF was a much more potent growth factor for MO7 cells than SF, particularly under serum-free conditions. Only GM-CSF, but not SF, was able to stimulate G1-->S transition of MO7 cells after factor deprivation for 24 h. Northern blot analyses showed also differential effects of GM-CSF and SF on the expression of some nuclear proto-oncogenes and G1 cyclins. GM-CSF (10 ng/ml), but not SF (20 ng/ml) increased the expression of c-myc and cyclin D2 mRNA, whereas both factors caused transient increases of c-fos and cyclin D3 mRNAs. When added simultaneously, GM-CSF and SF induced an at least additive increase of c-fos mRNA expression; this effect required the presence of fetal calf serum. No additive effects of GM-CSF and SF on c-myc, cyclin D2 or D3 mRNA expression were observed. C-jun and c-myb mRNAs were constitutively expressed in the MO7 cell line, but not further increased after stimulation with GM-CSF or SF for 15 min to 48 h. The inability of SF to induce growth promoting genes such as c-myc and cyclin D2 may explain why this cytokine does not support sustained proliferation of MO7 cells. These observations suggest that SF and GM-CSF exert different effects on the expression of genes involved in regulatory pathways of cell proliferation, but the molecular mechanism of synergy remains to be elucidated.
Assuntos
Ciclinas/genética , Regulação Leucêmica da Expressão Gênica , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Fatores de Crescimento de Células Hematopoéticas/metabolismo , Leucemia Megacarioblástica Aguda/genética , Transdução de Sinais , Fatores de Transcrição/genética , Divisão Celular , Sinergismo Farmacológico , Fase G1 , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Fatores de Crescimento de Células Hematopoéticas/genética , Fatores de Crescimento de Células Hematopoéticas/farmacologia , Humanos , Leucemia Megacarioblástica Aguda/metabolismo , Leucemia Megacarioblástica Aguda/patologia , Proto-Oncogenes/genética , Fase S , Fator de Células-Tronco , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/patologiaRESUMO
Chronic myelogenous leukemia is caused by a reciprocal chromosomal translocation of human chromosomes 9 and 22. The resulting fusion protein, p210Bcr/Abl, has enhanced tyrosine kinase activity compared with the normal cellular homologue, p145c-Abl. Expression of this chimeric protein in hematopoietic cell lines results in a rapid progression to growth factor independence and increased tyrosine phosphorylation of a number of unidentified cellular proteins. In this study, we show that the phosphorylation state of the hematopoietically restricted tyrosine kinase, p93c-Fes, is increased. Increased phosphorylation of p93c-Fes was detected in p210Bcr/Abl(+) human leukemic cell lines, in primary leukemic cells from patients with chronic myelogenous leukemia, and in myeloid cell lines expressing p210Bcr/Abl after transfection. Furthermore, p93c-Fes phosphorylation was increased by p210Bcr/Abl even when coexpressed in NIH 3T3 fibroblasts. v-abl expression was also found to increase the tyrosine phosphorylation of p93c-Fes. This increased phosphorylation was found to be accompanied by an increase in the ability of p93c-Fes to phosphorylate exogenous substrates. p93c-Fes could contribute to the transforming activity of the abl oncogenes.
Assuntos
Proteínas de Fusão bcr-abl/metabolismo , Proteínas Oncogênicas v-abl/metabolismo , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Tirosina/metabolismo , Sequência de Aminoácidos , Humanos , Dados de Sequência Molecular , Fosforilação , Proteínas Proto-Oncogênicas c-fes , Células Tumorais CultivadasRESUMO
A prospective study of excimer laser photorefractive keratectomy was performed with the aim of correcting a range of myopic errors between -1.00 and -10.00 dioptres. Corneal healing was monitored through the first post-operative year by serial assessments of refraction, contrast sensitivity, corneal haze, pachymetry and keratometry. Eighty-one patients were recruited for the study. At 12 months 81% were within +/- 1.00 dioptre of desired emmetropia and with unaided vision of 6/12. Contrast sensitivity was found by Pelli-Robson assessment to be reduced throughout the 12 months and regression analysis predicted recovery by 2 years. At 12 months, however, only 15% of patients were found to have lost a single line of best corrected Snellen acuity. Predictability of results was found to be greatest for initial errors less than -4.00 dioptres. No serious complications were observed during the follow-up period, but refraction had not stabilised in all cases and patients remain under review.
Assuntos
Córnea/cirurgia , Terapia a Laser/métodos , Miopia/cirurgia , Adulto , Sensibilidades de Contraste , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Miopia/fisiopatologia , Estudos Prospectivos , Acuidade Visual , CicatrizaçãoRESUMO
Granulocyte-macrophage colony-stimulating factor (GM-CSF) activates a broad range of myeloid cells through binding to high-affinity receptors (GM-CSF-R) consisting of at least two distinct subunits, GM-CSF-R alpha and GM-CSF-R beta. The genes of these GM-CSF-R subunits have been identified recently, but little is known about the regulation of their expression. In this study, we investigated the expression of the GM-CSF-R subunit genes in normal human monocytes. Out of a panel of various cytokines and factors tested, only interferon-gamma (IFN-gamma) affected the expression of one of the GM-CSF-R subunit genes by increasing the GM-CSF-R beta mRNA expression threefold to sixfold with no effect on GM-CSF-R alpha. Maximal effects occurred 2 to 4 hours after stimulation with 500 to 5,000 U/mL IFN-gamma. Nuclear run-on assays and mRNA half-life studies showed that IFN-gamma modestly enhanced the transcription of the GM-CSF-R beta gene and stabilized the GM-CSF-R beta mRNA, with the latter mechanism predominant. Pretreatment of the monocytes with cycloheximide did not abrogate the increase of GM-CSF-R beta mRNA expression induced by IFN-gamma, indicating that de novo protein synthesis was not required for this activity. When monocytes were exposed to IFN-gamma for 6 to 24 hours, the number of GM-CSF-R per cell was increased 79% as compared with controls, whereas the receptor affinity remained unchanged. These data indicate that the GM-CSF-R expression in monocytes may be upregulated by IFN-gamma via an increased expression of the beta subunit gene, involving both transcriptional and post-transcriptional mechanisms.
Assuntos
Citocinas/farmacologia , Interferon gama/farmacologia , Monócitos/fisiologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Animais , Northern Blotting , Linhagem Celular , Células Cultivadas , Cicloeximida/farmacologia , Expressão Gênica/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Humanos , Interleucina-1/farmacologia , Interleucina-2/farmacologia , Substâncias Macromoleculares , Monócitos/efeitos dos fármacos , RNA/sangue , RNA/genética , RNA/isolamento & purificação , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Transcrição Gênica/efeitos dos fármacos , Transfecção , Fator de Necrose Tumoral alfa/farmacologia , Regulação para Cima/efeitos dos fármacosRESUMO
The impact of acute and chronic portal hypertension on the dynamics of intestinal microvascular fluid exchange was examined in anesthetized, fasted, sham-operated control rats with normal portal pressures (CON), during acute elevations in portal pressure (APH) in control rats, and in rats in which chronic portal hypertension (CPH) was produced by calibrated stenosis of the portal vein 10 days prior to the experiments. Although intestinal blood flow and vascular resistance were not altered by APH in control rats, CPH was associated with an increased intestinal blood flow and reduced intestinal vascular resistance when compared with CON and APH. Intestinal capillary pressure and lymph flow were elevated in APH and CPH relative to control values. However, the increase in both variables was greater in CPH. The capillary filtration coefficient was elevated only in CPH. The transcapillary oncotic pressure gradient was not altered by APH or CPH. Interstitial fluid pressure was increased from -1.1 mmHg in CON to 3.9 mmHg during APH and to 5.0 mmHg in CPH. The results of this study indicate that chronic elevations in portal venous pressure produce larger increments in intestinal capillary pressure and filtration rate than do acute elevations in portal venous pressure of the same magnitude. However, the potential edemagenic effects of elevated capillary pressure in both acute and chronic portal hypertension are opposed by increases in lymph flow and interstitial fluid pressure.