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1.
Artigo em Inglês | MEDLINE | ID: mdl-34574457

RESUMO

This study provided a proof-of-concept and test-retest reliability of measures frequently used to assess a mental fatigue paradigm. After familiarization, 28 healthy men performed (40-min) the Rapid Visual Information Processing (RVP) test in a test-retest design, having mental fatigue sensation, motivation, emotional arousal, total mood disturbance, and electroencephalography (EEG) in the prefrontal cortex measured before and after the test. EEG was recorded during a 3-min rest so that the power spectral density of theta (3-7 Hz) and alpha (8-13 Hz) bands was calculated. Pre-to-post RVP test changes in psychological and physiological domains were compared (paired-T tests), and absolute (standard error of measurement (SEM) and minimal difference (MD)) and relative reliability (intraclass correlation coefficient (ICC)) were calculated. The RVP test induced an increase (p < 0.05) in mental fatigue sensation (120.9% (109.4; 132.4)) and total mood disturbance (3.5% (-6.3; 13.3)), and a decrease in motivation (-7.1% (-9.2; -5.1)) and emotional arousal (-16.2% (-19.1; -13.2)). Likewise, EEG theta (59.1% (33.2; 85.0); p < 0.05), but not alpha band, increased due to RVP test. All psychophysiological responses showed poor-to-moderate relative reliability. Changes in mental fatigue sensation and motivation were higher than SEM and MD, but changes in EEG theta band were higher only than SEM. Mental fatigue sensation, motivation, and EEG theta band were sensitive to distinguish a mental fatigue paradigm despite true mental fatigue effects on theta activity may be trivial.


Assuntos
Eletroencefalografia , Fadiga Mental , Humanos , Masculino , Motivação , Reprodutibilidade dos Testes , Descanso
2.
PLoS One ; 15(8): e0236592, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790792

RESUMO

Caffeine improves cycling time trial performance through enhanced motor output and muscle recruitment. However, it is unknown if caffeine further increases power output entropy. To investigate the effects of caffeine effects on cycling time trial performance and motor output entropy (MOEn), nine cyclists (VO2MAX of 55 ± 6.1 mL.kg.-1min-1) performed a 4 km cycling time trial (TT4km) after caffeine and placebo ingestion in a counterbalanced order. Power output data were sampled at a 2 Hz frequency, thereafter entropy was estimated on a sliding-window fashion to generate a power output time series. A number of mixed models compared performance and motor output entropy between caffeine and placebo every 25% of the total TT4km distance. Caffeine ingestion improved power output by 8% (p = 0.003) and increased MOEn by 7% (p = 0.018). Cyclists adopted a U-shaped pacing strategy after caffeine ingestion. MOEn mirrored power output responses as an inverted U-shape MOEn during the time trial. Accordingly, a strong inverse correlation was observed between MOEn and power output responses over the last 25% of the TT4km (p < 0.001), regardless of the ingestion, likely reflecting the end spurt during this period (p = 0.016). Caffeine ingestion improved TT4km performance and motor output responses likely due to a greater power output entropy.


Assuntos
Desempenho Atlético , Cafeína/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Resistência Física/efeitos dos fármacos , Adulto , Ciclismo , Entropia , Humanos , Masculino , Efeito Placebo
3.
Nutrients ; 11(10)2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31618910

RESUMO

The central and peripheral effects of caffeine remain debatable. We verified whether increases in endurance performance after caffeine ingestion occurred together with changes in primary motor cortex (MC) and prefrontal cortex (PFC) activation, neuromuscular efficiency (NME), and electroencephalography-electromyography coherence (EEG-EMG coherence). Twelve participants performed a time-to-task failure isometric contraction at 70% of the maximal voluntary contraction after ingesting 5 mg/kg of caffeine (CAF) or placebo (PLA), in a crossover and counterbalanced design. MC (Cz) and PFC (Fp1) EEG alpha wave and vastus lateralis (VL) muscle EMG were recorded throughout the exercise. EEG-EMG coherence was calculated through the magnitude squared coherence analysis in MC EEG gamma-wave (CI > 0.0058). Moreover, NME was obtained as the force-VL EMG ratio. When compared to PLA, CAF improved the time to task failure (p = 0.003, d = 0.75), but reduced activation in MC and PFC throughout the exercise (p = 0.027, d = 1.01 and p = 0.045, d = 0.95, respectively). Neither NME (p = 0.802, d = 0.34) nor EEG-EMG coherence (p = 0.628, d = 0.21) was different between CAF and PLA. The results suggest that CAF improved muscular performance through a modified central nervous system (CNS) response rather than through alterations in peripheral muscle or central-peripheral coupling.


Assuntos
Ritmo alfa/efeitos dos fármacos , Cafeína/administração & dosagem , Córtex Motor/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/administração & dosagem , Resistência Física/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Músculo Quadríceps/inervação , Adulto , Ciclismo , Cafeína/efeitos adversos , Estudos Cross-Over , Método Duplo-Cego , Eletromiografia , Humanos , Córtex Motor/fisiologia , Fadiga Muscular , Força Muscular/efeitos dos fármacos , Substâncias para Melhoria do Desempenho/efeitos adversos , Córtex Pré-Frontal/fisiologia , Fatores de Tempo
4.
Medicina (Kaunas) ; 55(9)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443551

RESUMO

Background and Objectives: The presence of endometrial-like tissue outside the uterine cavity is a key feature of endometriosis. Although endometriotic lesions appear to be histologically quite similar to the eutopic endometrium, detailed studies comparing both tissues are required because their inner and surrounding cellular arrangement is distinct. Thus, comparison between tissues might require methods, such as laser capture microdissection (LCM), that allow for precise selection of an area and its specific cell populations. However, it is known that the efficient use of LCM depends on the type of studied tissue and on the choice of an adequate protocol. Recent studies have reported the use of LCM in endometriosis studies. The main objective of the present study is to establish a standardized protocol to obtain good-quality microdissected material from eutopic or ectopic endometrium. Materials and Methods: The main methodological steps involved in the processing of the lesion samples for LCM were standardized to yield material of good quality to be further used in molecular techniques. Results: We obtained satisfactory results regarding the yields and integrity of RNA and protein obtained from LCM-processed endometriosis tissues. Conclusion: LCM can provide more precise analysis of endometriosis biopsies, provided that key steps of the methodology are followed.


Assuntos
Endometriose/metabolismo , Endométrio/metabolismo , Expressão Gênica , Microdissecção e Captura a Laser , Criocirurgia , Endometriose/genética , Endometriose/patologia , Endometriose/cirurgia , Endométrio/patologia , Endométrio/cirurgia , Feminino , Humanos , Proteínas/análise , RNA Mensageiro/análise , Coloração e Rotulagem
5.
J Cancer Res Ther ; 15(Supplement): S20-S26, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30900615

RESUMO

PURPOSE: Historically, the role of adjuvant radiotherapy (RT) for patients with adrenocortical carcinoma (ACC) has been controversial. The objective of this research is to review systematically the literature evaluating the role of adjuvant RT in patients with ACC undergone a surgical resection. MATERIALS AND METHODS: The electronic databases were searched for articles published until July 2017 without language restriction: Lilacs, Medline, Embase, and the Cochrane. Two reviewers independently appraised the eligibility criteria and extracted data. When possible, a fixed-effect meta-analysis was done. The systematic review (SR) followed all the criteria of the MOOSE guideline. RESULTS: Overall, 382 citations were identified. After the screening of titles and abstracts, 12 articles (eight case series [48 patients] and 4 cohort studies [136 patients]) were included in the final analysis. For the local recurrence, the pooled relative risk (RR) was RR = 0.46 (95% confidence interval: 0.28-0.75), in favor of adjuvant RT when compared with surgery alone. Concerning overall mortality and disease recurrence, no significant difference between adjuvant RT and surgery was detected, RR = 0.77 (CI 95% 0.49-1.22, P = 0.27), and RR = 0.95 (IC 95% 0.74-1.24, P = 0.67). In all cohort studies, the acute toxicities were graduated as mild and self-limited with nausea and fatigue being the most common symptoms. Only one case (1/50) of impairment of kidney function was detected as late toxicity in these studies. CONCLUSIONS: This SR and meta-analysis indicate that adjuvant RT dramatically reduces the local recurrence of ACC after surgery. Moreover, the treatment has a low acute and late toxicity, resulting in a high therapeutic index. Further, prospective studies are needed to confirm or refute the role of RT on survival and disease recurrence.


Assuntos
Neoplasias do Córtex Suprarrenal/terapia , Carcinoma Adrenocortical/terapia , Recidiva Local de Neoplasia/epidemiologia , Córtex Suprarrenal/patologia , Córtex Suprarrenal/cirurgia , Neoplasias do Córtex Suprarrenal/mortalidade , Neoplasias do Córtex Suprarrenal/patologia , Carcinoma Adrenocortical/mortalidade , Carcinoma Adrenocortical/patologia , Fadiga/epidemiologia , Fadiga/etiologia , Humanos , Náusea/epidemiologia , Náusea/etiologia , Recidiva Local de Neoplasia/prevenção & controle , Estudos Observacionais como Assunto , Estudos Prospectivos , Radioterapia Adjuvante/efeitos adversos , Radioterapia Adjuvante/métodos , Resultado do Tratamento
6.
Artigo em Inglês | MEDLINE | ID: mdl-33344980

RESUMO

Purpose: We analyzed the impact of sex, performance level and substantial speed reductions (SSR) on pacing in the VI Rio 24-h Marines Ultramarathon. This will provide insights into the importance of minimizing speed variations in relation to optimal pacing in endurance events. Methods: Runners (30 males and 21 females), classified as high- (HP) and low-performance (LP) ran the race while having their time recorded every 400 m. The pacing was analyzed as the first 10% (initial epoch), the following 80% (intermediate epoch) and the last 10% of the race (final epoch). The time percentage spent at speeds <3.5 km·h-1 (SSR), 3.5 to 5.9 km·h-1 (walking speed), 6.0 to 8.0 km·h-1 (walk-to-running transition speed) and > 8.0 km·h-1 (running speed) was calculated. Results: Runners showed a reverse J-shaped pacing (P < 0.001) regardless of sex and performance level, although male (P < 0.004) and HP runners (P < 0.001) have preserved a higher mean speed throughout the race. Male and HP runners spent more time at running speed (P < 0.001) and less time at SSR (P < 0.001) than female and LP runners. Total distance was inversely correlated with the number of SSR and speed CV in male (r = -0.47 and r = -0.64, respectively) and female (r = -0.61 and r = -0.47, respectively). Conclusion: Male, HP runners showed less SSR, conserving a higher mean speed with less variation throughout the race. Results suggest that conservative pacing strategies, with lower speeds in the beginning and higher speeds toward the end, may be the most adequate for different endurance running disciplines. Results also show different competition dynamics between men and women, which warrants further exploration in ultramarathons as well as other IAAF events.

7.
Arch Gynecol Obstet ; 297(4): 977-984, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29417283

RESUMO

PROPOSE: Endometriosis is a benign disease characterized by implantation and the growth of endometrial tissue outside the uterine cavity and it shares similarities with cancer. Lamin B1, p16 and p21 play a role on cell cycle regulation, development, cell repair and its activities are related to cancers. Considering the similarities between endometriosis and cancer, the aim of the present cross-sectional study is to detect p16, p21 and Lamin B1 in the ectopic endometrium of patients with endometriosis (n = 8) with eutopic (n = 8) and control endometrium (n = 8) and relate them to the maintenance and development of endometriosis. METHODS: Biopsies were obtained from both eutopic and ectopic, from deep infiltrating lesions, endometrium frozen and used for immunofluorescent (p16) or immunohistochemistry procedures (p16, p21, lamin B1). RESULTS: Detected higher lamin B1 in the eutopic endometrium when compared with ectopic endometrium, with no differences between endometriosis tissue with control endometrium. Similar presence of p16 in all groups of patients and no p21 detection was observed. CONCLUSION: We observed reduced detection of lamin B1 in the ectopic endometrium raising the possibility that the presence of senescent cells might be contributing to the maintenance and progression of endometriosis by apoptosis resistance and peritoneal stress inherent of the disease.


Assuntos
Biópsia , Endometriose/metabolismo , Endométrio/metabolismo , Lamina Tipo B/metabolismo , Doenças Uterinas/metabolismo , Adulto , Apoptose , Biomarcadores/metabolismo , Estudos de Casos e Controles , Estudos Transversais , Endometriose/sangue , Endometriose/patologia , Endométrio/patologia , Feminino , Imunofluorescência , Genes p16 , Humanos , Imuno-Histoquímica , Lamina Tipo B/genética , Doenças Uterinas/sangue , Doenças Uterinas/patologia , Útero/patologia
8.
Int J Sports Physiol Perform ; 13(2): 208-213, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-28605210

RESUMO

Cross-country mountain biking (XCO) is a popular high-intensity endurance cycling event, but XCO pacing strategy has not been fully examined. This study examined the pacing strategies of different XCO athletes during a laboratory-simulated XCO performance test. Brazilian cyclists classified as performance-cohort level 3 performed an XCO race simulation. The simulation consisted of four 10-km laps with a gradient of 0-10%. No group-vs-time interaction was found in lap time (P = .169), absolute (P = .719) and relative (P = .607) power output, ratings of perceived exertion (P = .182), or heart rate (P = .125). There was a time main effect, as athletes decreased power output by 0.3 W/kg throughout the XCO simulation, thereby resulting in a 1.6-min decrement per lap. The power output corresponding to the onset of blood lactate accumulation adequately represented the mean power of the first lap. These results showed that 2 groups of cyclists with different training status adopted similar pacing strategies during an XCO race simulation, as they both used a fast-starting pacing strategy followed by positive pacing that resulted in a linear decrease in power output at every lap.


Assuntos
Ciclismo/fisiologia , Resistência Física/fisiologia , Adulto , Antropometria , Brasil , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Percepção/fisiologia , Esforço Físico/fisiologia
9.
J. Phys. Educ. (Maringá) ; 29: e2915, 2018.
Artigo em Inglês | LILACS | ID: biblio-893605

RESUMO

ABSTRACT The origin of fatigue has been the focus of studies involved in sports performance, due to the necessity to clarify the mechanistic bases for the reduced capacity to perform considerable effort intensities. According to the traditional conception of fatigue, mechanisms may encompass peripheral and central sites of fatigue. Peripheral fatigue is understood as events related to an inefficient tissue oxygen delivery, metabolic accumulation, muscular acidosis and muscle substrate depletion. In contrast, the central fatigue is mostly related to events in the central nervous system (CNS) that may involve neurotransmitters changes, altered metabolic profile and elevated temperature. Therefore, the current review aimed to discuss the peripheral and central mechanisms of fatigue, thus driving interpretations of the phenomenon.


RESUMO A etiologia da fadiga tem sido objeto de estudo em pesquisas relacionadas ao desempenho esportivo em função da necessidade de esclarecer os mecanismos que reduzem a capacidade de manutenção do desempenho em intensidades elevadas de esforço. A concepção tradicional de fadiga assume que os mecanismos possam ser desencadeados em sítios de ação central ou periférica. A fadiga periférica é compreendida como uma oferta inadequada de oxigênio tecidual, acúmulo de metabólitos e depleção de substrato energético acelerando a acidose muscular. A fadiga central, por sua vez, oriunda do sistema nervoso central (SNC), apresenta alterações nos neurotransmissores, podendo alterar o perfil metabólico e temperatura do SNC. Desta forma, a presente revisão tem como intuito abordar os mecanismos de fadiga central e periférica, norteando futuras interpretações sobre o fenômeno.


Assuntos
Oxigênio , Exercício Físico , Fadiga Muscular , Glicogênio Fosforilase Muscular
10.
J Cancer Res Ther ; 12(2): 770-4, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27461649

RESUMO

OBJECTIVE: The intention of this study is to compare whole brain radiotherapy and stereotactic radiosurgery (WBRT + SRS) with WBRT in patients with 1-4 brain metastases to find a subgroup of patients that have a great benefit with aggressive treatment. MATERIALS AND METHODS: Between December 2002 and December 2013, 60 patients with 1-4 brain metastases were treated by WBRT + SRS. In this period, 60 patients treated with WBRT were matched with patients treated with WBRT + SRS. RESULTS: The median survival for the entire cohort was 8.3 months. In the univariate analysis, WBRT + SRS (0.031), the presence of extracranial disease (P = 0.02), Karnofsky performance score <70 (P = 0.0001), and age >65 (P = 0.001) years were significant factors for survival. In the entire cohort, the median survival for recursive partitioning analysis (RPA) classes I, II, and III was 11, 7, and 3 months, respectively (P = 0.0001). In a stratified analysis, only RPA class I achieved statistical significance for 1-year survival between the groups (WBRT + SRS = 51% and WBRT = 23%, P = 0.03). Cox regression analysis revealed WBRT + SRS, age >65 years, and extracranial disease as independent prognostic factors. In the univariate analysis, lesion volume ≤5 cm 3 (P = 0.002) and WBRT + SRS (P = 0.003) were the significant factors associated with better brain control. CONCLUSION: WBRT plus SRS was an independent prognostic factor for survival. However, the combined treatment appears to be justified only in patients with RPA I and lesion volume ≤5 cm 3, independently of the number of lesions.


Assuntos
Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/radioterapia , Irradiação Craniana , Radiocirurgia , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/secundário , Terapia Combinada , Irradiação Craniana/métodos , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Resultado do Tratamento , Carga Tumoral
11.
Cancer ; 122(13): 2004-11, 2016 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-27028170

RESUMO

BACKGROUND: The objective of this article was to report the results from a randomized clinical trial comparing intensity-modulated radiotherapy (IMRT) with 3-dimensonal conformal radiotherapy (3DCRT) for the treatment of prostate cancer on a hypofractionated schedule. METHODS: The authors randomly assigned 215 men who had localized prostate cancer to receive hypofractionated radiotherapy to a total dose of 70 grays (Gy) in 25 fractions (at 2.8 Gy per fraction) using either IMRT or 3DCRT. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity were prospectively evaluated according to modified Radiation Therapy Oncology Group criteria. Biochemical control was defined according to the Phoenix criteria (prostate-specific antigen nadir + 2 ng/mL). RESULTS: In total, 215 patients were enrolled in the IMRT group (n = 109) or the 3DCRT group (n = 106). The 3DCRT arm had a 27% rate of grade ≥ 2 acute GU toxicity compared with a 9% rate in the IMRT arm (P = .001) and a 24% rate of grade ≥ 2 acute GI toxicity compared with a 7% rate in the IMRT arm (P = .001). The maximal rate of grade ≥2 late GU toxicity during the entire period of follow-up was 3.7% in the IMRT group versus 12.3% in the 3DCRT group (P = .02). The maximal rate of grade ≥2 late GI toxicity during the entire follow-up was 6.4% in the IMRT group versus 21.7% in the 3DCRT group (P = .001). The 5-year rate of freedom from biochemical failure was 95.4% in the IMRT arm and 94.3% in the 3DCRT arm (P = .678). CONCLUSIONS: IMRT reduced the delivery of significant radiation doses to the bladder and rectum using a similar target volume. This dosimetric advantage resulted in a lower rate of acute/late grade ≥ 2 GI and GU toxicity for IMRT compared with 3DCRT. Cancer 2016;122:2004-11. © 2016 American Cancer Society.


Assuntos
Neoplasias da Próstata/radioterapia , Lesões por Radiação/epidemiologia , Radioterapia Conformacional/efeitos adversos , Radioterapia de Intensidade Modulada/efeitos adversos , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Antígeno Prostático Específico/metabolismo , Hipofracionamento da Dose de Radiação , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Resultado do Tratamento
12.
Appl Psychophysiol Biofeedback ; 41(1): 1-7, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26242877

RESUMO

This study examined the relationship between mood and rating of perceived exertion (RPE) during a simulated multiple-lap time trial (MLTT). Nineteen male cyclists performed a MLTT consisting of four 9.9 km laps, each lap with a gradient ranging from 0 to 10 %. Mood as measured by the Profile of Mood States Questionnaire (POMS) and perceived exertion as measured by the Borg CR100 scale (RPE) were obtained at the end of each lap. A categorical multiple regressive model, having median of POMS subscales as independent variables, was obtained to explain the variance in median RPE responses. Increases in POMS fatigue scores and decreases in POMS vigour scores were observed throughout the MLTT (P < 0.001). A linear increase in RPE during the MLTT was also observed (P < 0.001). POMS fatigue subscale scores accounted for 88 % of the variance in RPE during the MLTT (R(2) = 0.88, P = 0.002), and no other POMS subscale improved the final predictive model. With the exception of fatigue these results suggest that most aspects of mood do not have a discernable effect on RPE during a MLTT. The rate of increase in RPE can predict the MLTT endpoint.


Assuntos
Afeto/fisiologia , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Exercício Físico/fisiologia , Esforço Físico/fisiologia , Adulto , Fadiga/psicologia , Humanos , Masculino
13.
Clin Exp Pharmacol Physiol ; 42(10): 1098-107, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26173999

RESUMO

The use of high doses of adrenaline is common in critical patients, especially during cardiac arrest. During these situations, myocardial dysfunction can be a result of multiple factors, including adrenaline use. In addition, opioids have been shown to have anti-arrhythmic and anti-ischemic mechanisms that may confer cardiac protection. This study aimed to evaluate the effects of fentanyl on myocardial function in pigs exposed to high-dose adrenaline. After institutional ethics committee approval, 26 pigs were randomly allocated to receive either 20 µg/kg fentanyl (n = 10; fentanyl group) administered 5 min before five doses of adrenaline (20 µg/kg), equivalent-volume saline (n = 10; saline group) using the same adrenaline dosing protocol, or neither fentanyl nor adrenaline (n = 6; sham group). The fentanyl group showed lower levels of troponin at the end of the sixth hour compared with the saline group (1.91 ± 1.47 vs 5.44 ± 5.35 ng/mL, P = 0.019). Transmission electron microscopy and immunohistochemistry also showed less myocardial injury in the fentanyl group. The conclusion was reached that fentanyl attenuates myocardial injury caused by high-dose adrenaline without blunting the hemodynamic effect of adrenaline.


Assuntos
Cardiotônicos/farmacologia , Epinefrina/efeitos adversos , Fentanila/farmacologia , Coração/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Coração/fisiologia , Hemodinâmica/efeitos dos fármacos , Masculino , Miocárdio/metabolismo , Suínos , Fatores de Tempo , Troponina/metabolismo
14.
J Sports Sci ; 33(8): 777-85, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25356844

RESUMO

The aim of this study was to compare the psychological and physiological responses of self-selected and imposed sessions of equivalent intensities and durations and allowing to participants a free control of pace during the self-selected session. Seventeen participants completed three sessions on a cycle ergometer. Participant's VO2Peak and lactate threshold were measured during an incremental exercise test. During the second and third sessions, participants could view a virtual cyclist on a monitor. During the self-selected session, participants were allowed free control of the intensity and duration. To ensure that the imposed session replicated the self-selected session in intensity, participants were instructed to follow an additional virtual cyclist, which was displayed on a monitor using the CompuTrainer 3D software. Power output and physiological and psychological variables were recorded during the sessions. A two-way ANOVA showed no effect of condition for power output (P = 0.940), heart rate (HR) (P = 0.965), VO2 (P = 0.898), blood lactate (P = 0.667), Feeling Scale (P = 0.877), Felt Arousal Scale (P = 0.924) and CR100 (P = 0.939). A paired t-test showed no significant difference in Physical Activity Enjoyment Scale scores between sessions (P = 0.054). In contrast to previous studies, the self-selected session did not provide better affective responses than the imposed session with same intensity and duration.


Assuntos
Afeto/fisiologia , Comportamento de Escolha/fisiologia , Exercício Físico/psicologia , Adulto , Exercício Físico/fisiologia , Teste de Esforço , Feminino , Frequência Cardíaca , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio , Adulto Jovem
15.
Rev. bras. ciênc. mov ; 22(1): 168-174, 2014.
Artigo em Português | LILACS | ID: lil-733931

RESUMO

O modelo tradicional de fisiologia do exercício assume que existe um limite periférico (muscular) em todo exercício aeróbio máximo, devido à hipóxia severa causada pela oferta inadequada de oxigênio ao músculo esquelético. Este evento seria coincidente com o recrutamento de todas as unidades motoras disponíveis no músculo ativo, no mesmo instante. Entretanto, evidências recentes não se ajustam a estas predições. Pelo contrário, um modelo de regulação central do esforço defende a existência de reserva neurofisiológica em todo exercício aeróbio máximo. Nessa nova interpretação, o sistema nervoso central (SNC) modularia o recrutamento muscular para impedir a ativação de todas as unidades motoras ao mesmo tempo, e evitar o excesso de dano à matriz celular. Tal modulação realizada pelo SNC seria um mecanismo natural de defesa do organismo contra a falha catastrófica e o rigor mortis. Alguns resultados obtidos pelo Grupo de Estudo em Psicofisiologia do Exercício poderiam ser interpretados de acordo com a presença de uma reserva neurofisiológica, pois a potência mecânica máxima (WMAX) num teste incremental máximo foi aumentada após ingestão de cafeína e placebo percebido como cafeína, porém, sem alteração no consumo máximo de oxigênio (VO2MAX), sugerindo não haver limitação periférica. Entretanto, estudos devem ser desenhados para responder essa questão de forma mais consistente, incluindo medidas metabólicas e de excitabilidade dos músculos esqueléticos, mas também do SNC, durante exercício.


The traditional model of exercise physiology assumes that there would be a peripheral (muscular) limit in maximal aerobic exercises due to severe hypoxia derived from inadequate oxygen supply to the skeletal muscles. This event is to be coincident with the total recruitment of available motor units in the active muscles. However, recent evidence does not agree with these predictions. Rather, a centrally-regulated effort model argues that there is a neurophysiological reserve in all maximal aerobic exercises. In this new interpretation the central nervous system (CNS) would modulate the muscle recruitment to prevent the recruitment of all available motor units at the same time in order to avoid excessive harm in cellular matrixes. Such modulation performed by the CNS would be a natural mechanism to defend the body against catastrophic failure and rigor mortis. Some results obtained by the Exercise Psychophysiology Research Group may be interpreted according to this neurophysiological reserve as the peak power output (WPEAK) in a maximum incremental test was increased after caffeine and placebo perceived as caffeine ingestion, but without change in maximal oxygen consumption (VO2MAX), suggesting no peripheral limitation. Yet, studies including measures of metabolic and skeletal muscle excitability in addition to the CNS function during exercise may answer this question closer.


Assuntos
Sistema Nervoso Central , Músculo Esquelético , Oxigênio , Atividade Motora
16.
J Appl Physiol (1985) ; 112(9): 1434-6, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22383506

RESUMO

Several indicators have been used to analyze scientific journals, with the impact factor and the number of citations in a 2-yr calendar time frame (2-YRC) being the most common factors. However, considering that the Journal of Applied Physiology (JAPPL) appears monthly and that calculations of these indicators are based on citations of papers published in previous years, we hypothesized that articles published at the beginning of the year would be cited more in the 2-YRC compared with those appearing in the last issues of the year, a phenomena known as a relative age effect. Our objective was to confirm the existence of a relative age effect in the 2-YRC for original articles published in JAPPL. From 2005 to 2008, a total of 1,726 original articles were published, according to the Web of Science, and 9,973 citations in 2-YRC, varying from 0 to 45, with a mean of 5.78 for individual papers. Although there were no differences in the number of original articles published in a given month (P = 0.99), the 2-YRC varied considerably throughout the year, being higher for those earlier issues of the year, as shown by the linear regression analysis (r(2) = 0.76; P < 0.001). The 2-YRC began at 6.62 during the first 3 mo of the year, dropping by 10% at each 3-mo period. In summary, the longer an article has been out there, the more citations it collects. The relative age effect is a potential confounding variable for the assessment and interpretation of 2-YRC (using calendar years) from JAPPL original articles.


Assuntos
Pesquisa Biomédica/estatística & dados numéricos , Publicações Periódicas como Assunto/estatística & dados numéricos , Fisiologia/estatística & dados numéricos , Bibliometria , Fatores de Confusão Epidemiológicos , Fator de Impacto de Revistas , Modelos Lineares , Fatores de Tempo
17.
Rev. bras. educ. fís. esp ; 26(1): 29-36, jan.-mar. 2012. ilus, graf, tab
Artigo em Português | LILACS | ID: lil-624569

RESUMO

Objetivou-se comparar os efeitos de utilização da frequência cardíaca máxima medida (FCpico) vs. predita (FC Predita) na estimativa do VO2Máx em esteira pelo método de FC e VO2 de reserva. Dezoito homens (27,5 ± 7,1 anos, 73,7 ± 12,6 kg, 174,8 ± 10,2 cm) realizaram na primeira visita um teste progressivo máximo para determinar a FCpico. Nas duas visitas seguintes foram realizados os testes aeróbios submáximos em esteira com estágio de 6 min a 75% da FC de reserva. O VO2Máx foi estimado pelo uso conjunto das equações de FC, VO2 de reserva e equação de corrida do ACSM. Não foi observada diferença significativa (teste t) entre as estimativas de VO2Máx a partir da FCpredita e FCpico. O coeficiente de correlação intraclasse e erro típico da medida utilizando FCpredita e FCpico foram 0,89, 2,43 mL.kg-1.min-1 (5%) e 0,83, 2,43 mL.kg-1.min-1 (4,9%), respectivamente. O uso da abordagem estimada para determinação da FC máxima mostrou-se adequado para a determinação do VO2Máx com um pequeno erro típico da medida.


The objective was to determine the reliability of the VO2Max estimate on a treadmill using the measured (HRpeak) vs. the predicted (HRpredicted) maximum heart rate (HR). Eighteen men (27.5 ± 7.1 years, 73.7± 12.6 kg, 174.8 ± 10.2 cm) performed, in the first visit, a progressive test to determine the HRpeak. In the two following visits, submaximal aerobic tests were performed on a treadmill with a 6 min at 75% HR reserve. VO2Max was estimated by means of the equations of HR, VO2 reserve and the ACSM running equation. The intraclass correlation coefficient and the typical error of measurement using HRPredicted and HRpeak were 0.89, 2.43 ml.kg-1.min-1 (5%) and 0.83, 2.43 mL.kg-1.min-1 (4.9%), respectively. There was no significant difference (t test) between the estimates of VO2Max from the HRpeak and HRpredicted. The use of the HRpredicted was considered appropriate for VO2Max estimation, with a small typical error of measurement.


Assuntos
Humanos , Masculino , Adulto , Exercício Físico , Teste de Esforço , Frequência Cardíaca , Consumo de Oxigênio
18.
Endosc Ultrasound ; 1(3): 156-61, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24949354

RESUMO

OBJECTIVE: Endoscopic ultrasound-guided choledochoduodenostomy (EUS-CD) has become an alternative method after unsuccessful endoscopic retrograde cholangiopancreatography (ERCP) treatment. We present a case series study and its feasibility by using only a linear therapeutic channel echoendoscope to create both a biliary-enteral fistula and anatomic enteral recanalization. METHODS: We presented seven cases of unresectable periampullary cancer with both biliary and duodenal obstruction. In these cases, the EUS-guided technique might be an alternative to double stenting (biliary and enteral) in the same procedure and equipment. RESULTS: In all cases, the location of the biliary obstruction was in the distal common bile duct (CBD) and the grade of proximal dilation diameter varied from 15 mm to 20 mm. Two patients had type I (28.6%) and five had type II (71.4%) duodenal obstruction. Technical success of EUS-CD, by the stent placement, occurred in 100% of the cases. There were no early complications. Biliary drainage was effective clinically as well as in laboratory in 6 cases (6/7), by relieving obstructive jaundice and decreasing bilirubin levels. CONCLUSION: EUS equipment may offer an alternative to double stenting in the same procedure and with palliative propose.

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