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1.
Nutrients ; 12(4)2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32290122

RESUMO

Background. Gymnemic acids, from the plant Gymnema sylvestre (GS), selectively suppress taste responses to sweet compounds without affecting the perception of other taste elements. The aim of this study was to investigate the effect of consuming a GS-containing mint on the desire to consume high-sugar sweet foods directly thereafter. Methods. This study utilized a single-blind, crossover design comparing the consumption of a mint (dissolving tablet) containing 4 mg of gymnemic acids with an isocaloric placebo in 56 healthy young men and women. Participants were given samples of their favourite chocolate (varied between 14-18 g; energy varied between 292-370 kJ) and were directed to rate on their hunger on 100-mm visual analogue scales 30 s prior to consuming high-sugar sweet food (chocolate). They then consumed the GS mint or placebo mint and rated their perceived pleasantness and desire for more chocolate on separate visual analogue scales immediately following consumption of the high-sugar sweet food before being offered up to five additional servings (and asked to rate hunger, pleasantness and desire to eat more chocolate between each ingestion period). Results. The number of chocolate bars eaten decreased by 0.48 bars (21.3%) within a 15-min period of consumption of the GS mint (p = 0.006). Desire to eat more of the high-sugar sweet food (p = 0.011) and pleasantness of the high-sugar sweet food (p < 0.001) was reduced after GS mint intake. Those who reported having a 'sweet tooth' had a greater reduction in the pleasantness of chocolate (p = 0.037) and desire to eat more (p = 0.004) after consuming the GS mint for the first serving of a high-sugar sweet food following the mint. Conclusion. Consuming gymnema-containing mints compared to placebo significantly reduced the quantity of chocolate eaten mainly due to a decrease in the desire and pleasantness of consuming it.

2.
Int J Sports Med ; 41(1): 3-11, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791089

RESUMO

This study evaluated the morphological changes of the lower limb and associated hemodynamic responses to different lower-body compression pressures (COMPs) in physically active, healthy individuals at rest. Each of the 32 participants underwent three trials with three different degrees of lower-body compression applied: "Low" (2.2±1.4 mmHg), "Medium" (12.9±3.9 mmHg), and "High" (28.8±8.3 mmHg). In each COMP, a cross-sectional area of leg muscles (CSAmuscle), subcutaneous fat (CSAfat), superficial vessels (SupV), deep arteries (DA), and deep veins (DV) at the calf, knee, and thigh levels were measured using magnetic resonance imaging (MRI). Additionally, blood pressure (BP), heart rate (HR), cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR) were measured using Doppler ultrasound (USCOM®). With High COMP, calf CSAmuscle and SupV were smaller (p<0.01), whereas DA and DV were larger (p<0.05). Calf CSAfat, however, was similar among all COMPs. There were no major changes in CSAmuscle and CSAfat at knee and thigh levels. CO (3.2±0.9 L/min) and SV (51.9±16.4 mL) were higher (p<0.05) only with High COMP, but other hemodynamic variables showed no significant changes across different COMPs. The High COMP at the lower limb induces leg morphological changes and increases associated hemodynamic responses of physically active healthy individuals at rest.


Assuntos
Hemodinâmica/fisiologia , Extremidade Inferior/fisiologia , Meias de Compressão , Artérias/diagnóstico por imagem , Artérias/fisiologia , Pressão Sanguínea/fisiologia , Estudos Cross-Over , Feminino , Frequência Cardíaca/fisiologia , Humanos , Extremidade Inferior/irrigação sanguínea , Extremidade Inferior/diagnóstico por imagem , Imagem por Ressonância Magnética , Masculino , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiologia , Volume Sistólico/fisiologia , Gordura Subcutânea/irrigação sanguínea , Gordura Subcutânea/diagnóstico por imagem , Gordura Subcutânea/fisiologia , Ultrassonografia Doppler , Resistência Vascular/fisiologia , Veias/diagnóstico por imagem , Veias/fisiologia , Adulto Jovem
3.
Hum Mov Sci ; 66: 600-606, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31277034

RESUMO

Adolescents tend to exhibit more variability in their gait patterns than adults, suggesting a lack of gait maturity during this period of ongoing musculoskeletal growth and development. However, there is a lack of consensus over the age at which mature gait patterns are achieved and the factors contributing to gait maturation. Therefore, the purpose of this study was to investigate gait control and maturity in adolescents by determining if differences existed between adolescents and adults in a) the amount of spatiotemporal variability of walking and running patterns across a range of speeds, and b) how swiftly gait patterns are adapted to increasing gait speed during the walk-to-run transition. Forty-six adolescents (10-12-year-olds, n = 17; 13-14-year-olds, n = 12; and 15-17-year-olds, n = 17) and 12 young adults completed an incrementally ramped treadmill test (+0.2 km·h-1 every 30 s) to determine the preferred transition speed (PTS) during a walk-to-run transition. Age-related differences in the variability of stride lengths and stride durations were assessed across 4 speeds (self-selected walking speed, PTS - 0.06 m·s-1, PTS + 0.06 m·s-1, PTS + 0.83 m·s-1). Repeated measures ANOVAs (p < 0.05) compared coefficients of variation for these spatiotemporal parameters, while a one-way ANOVA compared the numbers of gait transitions and speed increments used to identify PTS between the adolescent groups and young adults. Compared to adults, 10-12yo exhibited more spatiotemporal variability during all gait conditions, while 13-17yo only exhibited more variability at PTS + 0.06 m·s-1. No age-dependent pattern was observed in PTS values, but 10-12yo completed more gait transitions over more speed increments than 15-17yo and adults. The development of mature gait patterns is thus a progressive process, with walking maturing at an earlier age than running. As 10-12yo were unable to swiftly adapt gait patterns to the changing task demands, their control mechanisms of gait may not have fully matured yet.

4.
Nutrients ; 11(7)2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31336633

RESUMO

Nitrate-rich beetroot juice supplementation has been shown to improve cardiovascular and cognitive function in younger and older adults via increased nitric oxide production. However, it is unclear whether the level of effects differs between the two groups. We hypothesized that acute supplementation with nitrate-rich beetroot juice would improve cardiovascular and cognitive function in older and younger adults, with the potential for greater improvements in older adults. Thirteen younger (18-30 years) and 11 older (50-70 years) adults consumed either 150 mL of nitrate-rich beetroot juice (BR; 10.5 mmol nitrate) or placebo (PL; 1 mmol nitrate) in a double-blind, crossover design, 2.25 h prior to a 30-min treadmill walk. Plasma nitrate and nitrite concentrations, blood pressure (BP), heart rate (HR), cognitive function, mood and perceptual tests were performed throughout the trial. BR consumption significantly increased plasma nitrate (p < 0.001) and nitrite (p = 0.003) concentrations and reduced systolic BP (p < 0.001) in both age groups and reduced diastolic BP (p = 0.013) in older adults. Older adults showed a greater elevation in plasma nitrite (p = 0.038) and a greater reduction in diastolic BP (p = 0.005) following BR consumption than younger adults. Reaction time was improved in the Stroop test following BR supplementation for both groups (p = 0.045). Acute BR supplementation increased plasma nitrite concentrations and reduced diastolic BP to a greater degree in older adults; whilst systolic BP was reduced in both older and younger adults, suggesting nitrate-rich BR may improve cardiovascular health, particularly in older adults due to the greater benefits from reductions in diastolic BP.


Assuntos
Beta vulgaris/química , Pressão Sanguínea/efeitos dos fármacos , Nitratos/administração & dosagem , Nitritos/sangue , Raízes de Plantas/química , Adolescente , Adulto , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Sucos de Frutas e Vegetais , Frequência Cardíaca , Humanos , Nitratos/metabolismo , Adulto Jovem
5.
Front Physiol ; 10: 409, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31031638

RESUMO

Introduction: There is controversy in the literature in regards of the link between training load and injury rate. Thus, the aims of this non-interventional study were to evaluate relationships between pre-season training load with biochemical markers, injury incidence and performance during the first month of the competitive period in professional soccer players. Materials and Methods: Healthy professional soccer players were enrolled in this study over two pre-season periods. Data sets were available from 26 players during the first season (2014-2015) and 24 players during the second season (2015-2016) who completed two pre-season periods (6 weeks each). External training load was assessed from all athletes during training using Global Positioning System (GPS). Internal training load was monitored after each training session using rate of perceived exertion (RPE). Before and after each pre-season, blood samples were taken to determine plasma lactate dehydrogenase (LDH), creatine kinase (CK) and C-reactive protein (CRP). Injury incidence and overall performance (ranking of the team after the first five official games of the championship) were recorded for both seasons separately. Results: There was no statistically significant difference in mean RPE values of the two-preparation periods (2737 ± 452 and 2629 ± 786 AU, p = 0.492). The correlational analysis did not reveal significant associations between internal and external training load (RPE and GPS data) and biological markers. There was a significant positive correlation between RPE and LDH during the 2015/2016 season (r = 0.974, p = 0.001). In addition, a significant negative correlation was found between total distance >20 km/h and CRP during the 2015-2016 season (r = -0.863, p = 0.027). The injury rates for the two seasons were 1.76 and 1.06 per 1000 h exposure for the 2014-2015 and 2015-2016 seasons, respectively (p = 0.127). Conclusion: Our study showed that pre-season training load is not associated with overall team performance. This association is most likely multifactorial and other factors (e.g., technical and tactical level of the team, opponents, environment) may play an important role for the collective team performance. Our findings may help coaches to better prepare their athletes during pre-season.

6.
Int J Sports Physiol Perform ; 14(8): 1096-1102, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30702380

RESUMO

PURPOSE: To examine the validity and reliability of a novel futsal special performance test (FSPT) as a measure of futsal performance and skills. METHODS: Thirty-six futsal players with different levels of experience were recruited and divided into 2 groups (elite and nonelite). Players participated in 4 sessions (at least 7 d apart): (1) familiarization session, (2) anaerobic power (Wingate test), (3) FSPT trial 1, and (4) FSPT trial 2. The FSPT was carried out on a futsal court (wooden sprung floor) and skills such as dribbling, rotation, long and short passing, and shooting were examined. Content validity was assessed by 6 experienced futsal coaches and instructors. RESULTS: There was a significant correlation between FSPT and various aspects of anaerobic power (r = .5-.91; P ≤ .001). Moreover, significant large correlations were observed between test and retest of FSPT (r = .77; 95% confidence interval [CI], .56-.98; P ≤ .001). All instructors and coaches confirmed the content validity. There was high interrater reliability of the FSPT (r = .89; 95% CI, .85-.93; P < .001). FSPT total time (P = .001), penalty time (P = .022), and performance time (P = .001) were superior in elite relative to nonelite players. Anaerobic power was greater in elite players (P < .001). CONCLUSION: The results support the use of the FSPT to assess futsal players' performance in conjunction with skill and anaerobic fitness.


Assuntos
Desempenho Atlético , Teste de Esforço/normas , Aptidão Física , Futebol , Adulto , Anaerobiose , Atletas , Humanos , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
8.
Nutrients ; 10(10)2018 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-30248915

RESUMO

Caffeine use is widespread among athletes following its removal from the World Anti-Doping Agency banned list, with approximately 75% of competitive athletes using caffeine. While literature supports that caffeine has a small positive ergogenic effect for most forms of sports and exercise, there exists a significant amount of inter-individual difference in the response to caffeine ingestion and the subsequent effect on exercise performance. In this narrative review, we discuss some of the potential mechanisms and focus on the role that genetics has in these differences. CYP1A2 and ADORA2A are two of the genes which are thought to have the largest impact on the ergogenicity of caffeine. CYP1A2 is responsible for the majority of the metabolism of caffeine, and ADORA2A has been linked to caffeine-induced anxiety. The effects of CYP1A2 and ADORA2A genes on responses to caffeine will be discussed in detail and an overview of the current literature will be presented. The role of these two genes may explain a large portion of the inter-individual variance reported by studies following caffeine ingestion. Elucidating the extent to which these genes moderate responses to caffeine during exercise will ensure caffeine supplementation programs can be tailored to individual athletes in order to maximize the potential ergogenic effect.


Assuntos
Cafeína/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Citocromo P-450 CYP1A2/genética , Exercício Físico/fisiologia , Substâncias para Melhoria do Desempenho/farmacologia , Resistência Física/genética , Receptor A2A de Adenosina/genética , Ansiedade/genética , Atletas/psicologia , Desempenho Atlético/psicologia , Citocromo P-450 CYP1A2/metabolismo , Suplementos Nutricionais , Doping nos Esportes , Exercício Físico/psicologia , Humanos , Individualidade , Resistência Física/efeitos dos fármacos , Medicina de Precisão , Receptor A2A de Adenosina/metabolismo
9.
Sports Med ; 48(10): 2425-2441, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30094798

RESUMO

INTRODUCTION: Caffeine is a widely used ergogenic aid with most research suggesting it confers the greatest effects during endurance activities. Despite the growing body of literature around the use of caffeine as an ergogenic aid, there are few recent meta-analyses which quantitatively assess the effect of caffeine on endurance exercise. OBJECTIVES: To summarise studies which have investigated the ergogenic effects of caffeine on endurance time-trial performance and to quantitatively analyse the results of these studies to gain a better understanding of the magnitude of caffeine's ergogenic effect on endurance time-trial performance. METHODS: A systematic review was carried out on randomised placebo-controlled studies investigating the effects of caffeine on endurance performance and a meta-analysis was conducted to determine the ergogenic effect of caffeine on endurance time-trial performance. RESULTS: 44 studies met the inclusion criteria and were included in the meta-analysis. Caffeine has a small but evident effect on endurance performance when taken in moderate doses (3-6 mg·kg-1) as well as an overall improvement following caffeine compared to placebo in mean power output (2.92 ± 2.18%; Effect Size = 0.22 ± 0.15) and time-trial completion time (2.26 ± 2.60%; Effect Size = 0.28 ± 0.12). However, differences in responses to caffeine ingestion have been shown, with two studies reporting slower time-trial performance while five studies reported lower mean power output during the time-trial. Caffeine can be used effectively as an ergogenic aid when taken in moderate doses, such as during sports when a small increase in endurance performance can lead to significant differences in placements as athletes are often separated by small margins.

10.
Sports Med ; 48(8): 1913-1928, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29876876

RESUMO

BACKGROUND: Caffeine is a widely used ergogenic aid with most research suggesting it confers the greatest effects during endurance activities. Despite the growing body of literature around the use of caffeine as an ergogenic aid, there are few recent meta-analyses that quantitatively assess the effect of caffeine on endurance exercise. OBJECTIVES: To summarise studies that have investigated the ergogenic effects of caffeine on endurance time-trial performance and to quantitatively analyse the results of these studies to gain a better understanding of the magnitude of the ergogenic effect of caffeine on endurance time-trial performance. METHODS: A systematic review was carried out on randomised placebo-controlled studies investigating the effects of caffeine on endurance performance and a meta-analysis was conducted to determine the ergogenic effect of caffeine on endurance time-trial performance. RESULTS: Forty-six studies met the inclusion criteria and were included in the meta-analysis. Caffeine has a small but evident effect on endurance performance when taken in moderate doses (3-6 mg/kg) as well as an overall improvement following caffeine compared to placebo in mean power output (3.03 ± 3.07%; effect size = 0.23 ± 0.15) and time-trial completion time (2.22 ± 2.59%; effect size = 0.41 ± 0.2). However, differences in responses to caffeine ingestion have been shown, with two studies reporting slower time-trial performance, while five studies reported lower mean power output during the time-trial. CONCLUSION: Caffeine can be used effectively as an ergogenic aid when taken in moderate doses, such as during sports when a small increase in endurance performance can lead to significant differences in placements as athletes are often separated by small margins.


Assuntos
Desempenho Atlético , Cafeína/administração & dosagem , Café/química , Substâncias para Melhoria do Desempenho/administração & dosagem , Resistência Física/efeitos dos fármacos , Estimulantes do Sistema Nervoso Central , Exercício Físico , Humanos , Esportes
11.
J Sci Med Sport ; 21(10): 1062-1067, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29793800

RESUMO

OBJECTIVES: While previous studies have demonstrated an ergogenic effect of sport compression garments in exercise performance and recovery, the possible underlying mechanisms remain unclear. Claims for improved venous return from wearing sport compression garments with a low compression pressure remain unproven. The aim of this study was to determine the pressure profile exerted by low-pressure sports compression tights, and to investigate using a non-invasive Doppler ultrasound cardiac output monitor (USCOM), whether the compression applied will influence haemodynamic responses during an orthostatic challenge. DESIGN: A randomized-crossover design. METHODS: Thirty-three healthy participants (18 male and 15 female) underwent two trials, each consisting of lying supine and 70° head-up tilt wearing either a low-pressure sports compression tights (CT) or track pants (CON). Stroke volume (SV) and cardiac output (CO) were measured non-invasively using USCOM; heart rate (HR) and non-invasive blood pressure were measured, and systemic vascular resistance (SVR) was derived. RESULTS: The SV and CO was lower at 70° head-up tilt than in supine but wearing CT attenuated the decline in SV (25.9±11.6cm3 CT vs. 35.9±11.4cm3 CON, p<0.001), CO (1.1±0.7 Lmin-1 CT vs. 1.4±0.6 Lmin-1 CON, p<0.05), HR (8.8±8.4 beatmin-1 CT vs. 15.9±9.7 beatmin-1 CON, p<0.001) and SVR (740±504dscm-5 CT vs. 961±560dscm-5 CON, p<0.005). The mean arterial pressure (3.3±4.1mmHg CT vs. 3.6±4.5mm Hg CON, p>0.05) was similar in both trials. CONCLUSIONS: Healthy individuals wearing low-pressure sports compression tights experienced less severe haemodynamic disturbance such as decreases in CO, SV, HR and SVR during an orthostatic challenge.


Assuntos
Hemodinâmica , Postura , Meias de Compressão , Pressão Sanguínea , Débito Cardíaco , Estudos Cross-Over , Feminino , Frequência Cardíaca , Humanos , Masculino , Resistência Vascular , Adulto Jovem
12.
Hum Mov Sci ; 57: 1-12, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29121506

RESUMO

Human locomotion is a fundamental skill that is required for daily living, yet it is not completely known how human gait is regulated in a manner that seems so effortless. Gait transitions have been analyzed to gain insight into the control mechanisms of human locomotion since there is a known change that occurs as the speed of locomotion changes. Specifically, as gait speed changes, there is a spontaneous transition between walking and running that occurs at a particular speed. Despite the growing body of research on the determinants of this preferred transition speed and thus the triggering mechanisms of human gait transitions, a clear consensus regarding the control mechanisms of gait is still lacking. Therefore, this article reviews the determinants of the preferred transition speed using concepts of the dynamic systems theory and how these determinants contribute to four proposed triggers (i.e. metabolic efficiency, mechanical efficiency, mechanical load and cognitive and perceptual) of human gait transitions. While individual anthropometric and strength characteristics influence the preferred transition speed, they do not act to trigger a gait transition. The research has more strongly supported the mechanical efficiency and mechanical load determinants as triggering mechanisms of human gait transitions. These mechanical determinants, combined with cognitive and perceptual processes may thus be used to regulate human gait patterns through proprioceptive and perceptual feedback as the speed of locomotion changes.


Assuntos
Marcha/fisiologia , Corrida/fisiologia , Velocidade de Caminhada , Caminhada/fisiologia , Antropometria , Fenômenos Biomecânicos , Cognição , Humanos , Propriocepção , Estresse Mecânico
13.
J Sports Sci ; 36(3): 340-347, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28349730

RESUMO

Carbohydrate (CHO) ingestion enhances "feel-good" responses during acute exercise but no study has examined the effect of regular ingestion of CHO on affective valence. We investigated the effect of CHO ingestion on perceptual responses and perceived work intensity of individual exercise sessions throughout a 10-week cycling ("spin") exercise intervention. We also assessed whether any changes in affect and/or perceived work intensity would influence health and fitness parameters. Twelve recreational exercisers (46 ± 9 years; nine females and three males) were randomly allocated to either CHO (7.5% CHO; 5 mL · kg-1 per exercise session; n = 6; CHO) or placebo (0% CHO, taste- and volume-matched solution; n = 6; PLA) groups. Participants exercised 2 × 45-min per week, over a 10-week intervention period. Perceptual measures of exertion (RPE), affect (feeling scale, FS) and activation (felt arousal scale, FAS) were assessed after each exercise session. The FAS ratings increased over time in CHO but decreased throughout the intervention in PLA (P = 0.03). There were no differences in heart rate (P = 0.70), RPE (P = 0.05) and FS (P = 0.84) between trials. Furthermore, no changes in health and fitness parameters were observed over time or between groups. CHO ingestion enhanced ratings of activation in recreational exercisers throughout a 10-week cycling intervention.


Assuntos
Afeto/fisiologia , Ciclismo/fisiologia , Ciclismo/psicologia , Carboidratos da Dieta/administração & dosagem , Percepção/fisiologia , Esforço Físico/fisiologia , Antropometria , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Aptidão Física/fisiologia
14.
Nutrients ; 9(11)2017 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-29077028

RESUMO

Supplementation with nitrate (NO3-)-rich beetroot juice has been shown to improve exercise performance and cardiovascular (CV) responses, due to an increased nitric oxide (NO) availability. However, it is unclear whether these benefits are greater in older adults who have an age-related decrease in NO and higher risk of disease. This systematic review examines 12 randomised, crossover, control trials, investigating food-based NO3- supplementation in older adults and its potential benefits on physiological and cognitive performances, and CV, cerebrovascular and metabolic health. Four studies found improvements in physiological performance (time to exhaustion) following dietary NO3- supplementation in older adults. Benefits on cognitive performance were unclear. Six studies reported improvements in CV health (blood pressure and blood flow), while six found no improvement. One study showed improvements in cerebrovascular health and two found no improvement in metabolic health. The current literature indicates positive effects of dietary NO3- supplementation in older adults on physiological performance, with some evidence indicating benefits on cardiovascular and cerebrovascular health. Effects on cognitive performance were mixed and studies on metabolic health indicated no benefit. However, there has been limited research conducted on the effects of dietary NO3- supplementation in older adults, thus, further study, utilising a randomised, double-blind, control trial design, is warranted.


Assuntos
Envelhecimento/metabolismo , Beta vulgaris/química , Pressão Sanguínea/efeitos dos fármacos , Circulação Cerebrovascular/efeitos dos fármacos , Cognição/efeitos dos fármacos , Suplementos Nutricionais , Nitratos/farmacologia , Idoso , Doenças Cardiovasculares/metabolismo , Feminino , Humanos , Masculino , Doenças Metabólicas/metabolismo , Óxido Nítrico/metabolismo
15.
J Int Soc Sports Nutr ; 14: 27, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28811748

RESUMO

BACKGROUND: Saliva is a useful diagnostic tool for analysis in sports, exercise and nutrition research, as collection is easy and non-invasive and it contains a large number of analytes affected by a range of physiological and pathological stressors and conditions. This study examined key salivary electrolytes and stress and immune markers in males and females at rest and during exercise. METHODS: Unstimulated whole saliva from 20 healthy, recreationally active participants (8 males and 12 females) was analysed for flow rate, osmolality, sodium (Na+), potassium (K+), chloride (Cl-), secretory immunoglobulin A (SIgA), α-amylase activity and cortisol during both rest and moderate intensity (70% peak power) cycling exercise in a randomised crossover design. Each trial lasted 60 min and sampling was carried out at 15 and 45 min after the start of the trial. Saliva was collected using the gold-standard drool method; participants were required to provide at least 1 mL sample over 2 or 3-min period. RESULTS: Females showed a greater response to steady-state exercise stress than males, with significant increases in osmolality (P < 0.001), α-amylase activity (P = 0.001) and secretion rate (P = 0.023) and SIgA secretion rate (P = 0.023), with trends for an increase in K+ (P = 0.053) and decrease in Cl- (P = 0.067). There were no differences between rest and exercise for any salivary analytes in males. In addition, females showed a trend for higher levels of cortisol than males at both rest (P = 0.099) and exercise (P = 0.070), as well as a higher heart rate (P < 0.001) and greater ratings of perceived exertion (P < 0.001) during the exercise trial. The coordination of the two stress response pathways (α-amylase vs cortisol) was positive in males (r = 0.799; P = 0.017) yet negative in females (r = -0.475; P = 0.036). CONCLUSIONS: Males and females show a markedly different response to steady-state exercise stress as measured in unstimulated whole saliva.


Assuntos
Eletrólitos/análise , Exercício Físico/fisiologia , Descanso/fisiologia , Saliva/química , Adulto , Biomarcadores/análise , Estudos Cross-Over , Feminino , Frequência Cardíaca , Humanos , Hidrocortisona/análise , Imunidade nas Mucosas , Imunoglobulina A Secretora/análise , Masculino , Concentração Osmolar , Estresse Fisiológico , Adulto Jovem , alfa-Amilases/análise
16.
Trials ; 18(1): 338, 2017 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-28728559

RESUMO

BACKGROUND: Despite the reduction in glycemic derangement in patients with type 1 diabetes mellitus (T1D) through dietary and therapeutic adjustments implemented before, during and after continuous exercise, evidence for its effectiveness with intermittent forms of exercise, such as soccer, is still lacking. METHODS/DESIGN: We designed a study protocol for a randomized, crossover, double-blinded, controlled trial, for the evaluation of the effect that a strategy of dietary and therapeutic modifications may have on safety and performance of persons with T1D in soccer training sessions and cognitive testing. Inclusion criteria comprise: age older than 18 years, more than 2 years since T1D diagnosis, low C-peptide level, a stable insulin regimen, HbA1c less than 9.0% and regular participation in soccer activities. Our primary outcome evaluates safety regarding hypoglycemia events in patients using dietary and therapeutic adjustments, compared with the performance under the implementation of current American Diabetes Association (ADA) usual recommendations for nutritional and pharmacological adjustments for exercise. Additionally, we will evaluate as secondary outcomes: soccer performance, indexed by performance in well-established soccer skill tests, cognitive functions (indexed by Stroop, digital vigilance test (DVT), Corsi block-tapping task (CBP), and rapid visual information processing (RVIP) tests), and glycemic control measured with a continuous glucose monitor (CGM). DISCUSSION: Dietary and insulin adjustments standardized under a 4-step method strategy have never been tested in a clinical trial setting with intermittent forms of exercise, such as soccer. We hypothesize that through this strategy we will observe better performance by persons with T1D in soccer and cognitive evaluations, and more stable control of glycemic parameters before, during and after exercise execution, indexed by CGM measurements. TRIAL REGISTRATION: ISRCTN, ISRCTN17447843. Registered on 5 January 2017.


Assuntos
Glicemia/efeitos dos fármacos , Diabetes Mellitus Tipo 1/dietoterapia , Diabetes Mellitus Tipo 1/tratamento farmacológico , Exercício Físico , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Futebol , Biomarcadores/sangue , Glicemia/metabolismo , Protocolos Clínicos , Costa Rica , Estudos Cross-Over , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/diagnóstico , Método Duplo-Cego , Teste de Esforço , Hemoglobina A Glicada/metabolismo , Humanos , Hipoglicemia/sangue , Hipoglicemia/etiologia , Hipoglicemia/prevenção & controle , Hipoglicemiantes/efeitos adversos , Insulina/efeitos adversos , Monitorização Ambulatorial/métodos , Testes Neuropsicológicos , Projetos de Pesquisa , Fatores de Tempo , Resultado do Tratamento
17.
Artigo em Inglês | MEDLINE | ID: mdl-28138315

RESUMO

BACKGROUND: The aim of this study was to investigate whether mouth rinsing or ingesting carbohydrate (CHO) solutions impact on perceptual responses during exercise. METHODS: Nine moderately trained male cyclists underwent a 90-min glycogen-reducing exercise, and consumed a low CHO meal, prior to completing an overnight fast. A 1-h cycle time trial was performed the following morning. Four trials, each separated by 7 days, were conducted in a randomized, counterbalanced study design: 15% CHO mouth rinse (CHOR), 7.5% CHO ingestion (CHOI), placebo mouth rinse (PLAR) and placebo ingestion (PLAI). Solution volumes (1.5 ml · kg-1 ingestion trials and 0.33 ml · kg-1 rinsing trials) were provided after every 12.5% of completed exercise. Perceptual scales were used to assess affective valence (feeling scale, FS), arousal (felt arousal scale, FAS), exertion (ratings of perceived exertion, RPE) and mood (profile of mood states, POMS) before, during and immediately after exercise. RESULTS: There was no difference in RPE (CHOI, 14.0 ± 1.9; CHOR, 14.2 ± 1.7; PLAI, 14.6 ± 1.8; PLAR, 14.6 ± 2.0; P = 0.35), FS (CHOI, 0.0 ± 1.7; CHOR, -0.2 ± 1.5; PLAI, -0.8 ± 1.4; PLAR, -0.8 ± 1.6; P = 0.15), or FAS (CHOI, 3.6 ± 1.1; CHOR, 3.5 ± 1.0; PLAI, 3.4 ± 1.4; PLAR, 3.3 ± 1.3; P = 0.725) scores between trials. While overall POMS score did not appear to differ between trials, the 'vigour' subscale indicated that CHOI may facilitate the maintenance of 'vigour' scores over time, in comparison to the steady decline witnessed in other trials (P = 0.04). There was no difference in time trial performance between trials (CHOI, 65.3 ± 4.8 min; CHOR, 68.4 ± 3.9 min; PLAI, 68.7 ± 5.3 min; PLAR, 68.3 ± 5.2 min; P = 0.21) but power output was higher in CHOI (231.0 ± 33.2 W) relative to other trials (221-223.6 W; P < 0.01). CONCLUSIONS: In a CHO-reduced state, mouth rinsing with a CHO solution did not impact on perceptual responses during high-intensity exercise in trained cyclists and triathletes. On the other hand CHO ingestion improved perceived ratings of vigour and increased power output during exercise.


Assuntos
Ciclismo , Carboidratos/administração & dosagem , Suplementos Nutricionais , Adulto , Afeto/efeitos dos fármacos , Carboidratos/farmacologia , Humanos , Masculino , Antissépticos Bucais , Resistência Física/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Esportiva , Resultado do Tratamento
18.
J Exerc Sci Fit ; 15(2): 76-80, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29541136

RESUMO

Futsal, the 5-a-side version of soccer (i.e. 1 goalkeeper and 4 outfield players), was introduced in 1930 and continues to grow in popularity around the world. Competitive games comprise of two 20-min periods of high-intensity and intermittent activities requiring substantial physical, tactical, and technical efforts from the players. A greater understanding of the physical and skill requirements will aid the development of futsal and enable practitioners to undertake appropriate training regimes for the demands of the sport. The objective of this review is to examine key aspects of futsal such as match analysis, physiological demands, energy requirements, fitness measurements, and skill requirements. Futsal players experience fatigue as the game progresses due to the high-intensity nature of the game and the repeated maximal sprint efforts required. The intermittent nature of the sport necessitates the use of aerobic and anaerobic energy pathways throughout exercise. Therefore, a futsal player needs to have a great capacity of intermittent endurance, repeated sprint ability, and leg power, while technical aspects include the ability of high level shooting and passing skills, agility and coordination. Future research is warranted to help practitioners develop more specific tests into futsal performance, especially with regards skill.

19.
J Int Soc Sports Nutr ; 13: 46, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27980499

RESUMO

BACKGROUND: The aim of this study was to examine the influence of caffeine supplementation on knee flexor and knee extensor strength before, during and after intermittent running exercise in female team-sport players taking oral contraceptive steroids (OCS). METHOD: Ten healthy females (24 ± 4 years; 59.7 ± 3.5 kg; undertaking 2-6 training sessions per week) taking low-dose monophasic oral contraceptives of the same hormonal composition took part in a randomised, double-blind, placebo-controlled crossover-design trial. Sixty minutes following the ingestion of a capsule containing 6 mg∙kg-1 body mass anhydrous caffeine or artificial sweetener (placebo), participants completed a 90-min intermittent treadmill-running protocol. Isometric strength performance and eccentric and concentric strength and power of the knee flexors and knee extensors (using isokinetic dynamometer), as well as countermovement jump (CMJ), was measured before, during and after the exercise protocol, as well as ~12 h post-exercise. Blood samples were taken before, during and post-exercise to measure glucose, insulin and free fatty acids (FFA). RESULTS: Caffeine supplementation significantly increased eccentric strength of the knee flexors (P < 0.05) and eccentric power of both the knee flexors (P < 0.05) and extensors (P < 0.05). However, there was no effect on isometric or concentric parameters, or CMJ performance. FFA was elevated with caffeine supplementation over time (P < 0.05) while levels of glucose and insulin were not affected by caffeine intake. CONCLUSION: Caffeine supplementation increased eccentric strength and power in female team-sport players taking OCS both during an intermittent running protocol and the following morning.


Assuntos
Desempenho Atlético/fisiologia , Cafeína/administração & dosagem , Força Muscular/efeitos dos fármacos , Esportes , Adulto , Estudos Cross-Over , Método Duplo-Cego , Exercício Físico , Feminino , Humanos , Joelho , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiologia , Placebos , Corrida , Adulto Jovem
20.
J Int Soc Sports Nutr ; 13: 19, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27110224

RESUMO

BACKGROUND: The effect of mouth rinsing with a carbohydrate (CHO) solution on exercise performance is inconclusive with no benefits observed in the fed state. This study examined the effect of CHO mouth rinse or CHO ingestion on performance in 9 moderately trained male cyclists. METHODS: Four trials were undertaken, separated by 7 days, in a randomized, counterbalanced design. Each trial included a 90-min glycogen-reducing exercise protocol, immediately followed by a low CHO meal and subsequent overnight fast; the following morning a 1-h cycling time trial was conducted. The trials included 15 % CHO mouth rinse (CHOR), 7.5 % CHO ingestion (CHOI), placebo mouth rinse and placebo ingestion. Solutions were provided after every 12.5 % of completed exercise: 1.5 mL · kg(-1) and 0.33 mL · kg(-1) body mass during ingestion and rinse trials, respectively. During rinse trials participants swirled the solution for 8 s before expectorating. Blood samples were taken at regular intervals before and during exercise. RESULTS: Performance time was not different between trials (P = 0.21) but the 4.5-5.2 % difference between CHOI and other trials showed moderate practical significance (Cohen's d 0.57-0.65). Power output was higher in CHOI relative to other trials (P < 0.01). There were no differences between CHOR and placebo groups for any performance variables. Plasma glucose, insulin and lactate concentrations were higher in CHOI relative to other groups (P < 0.05). CONCLUSIONS: In a fasted and glycogen-reduced state ingestion of a CHO solution during high-intensity exercise enhanced performance through stimulation of insulin-mediated glucose uptake. The CHO mouth rinsing had neither ergogenic effects nor changes in endocrine or metabolic responses relative to placebo.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo , Carboidratos da Dieta , Metabolismo Energético/fisiologia , Antissépticos Bucais , Substâncias para Melhoria do Desempenho/metabolismo , Adulto , Ciclismo/fisiologia , Glicemia , Carboidratos da Dieta/metabolismo , Ingestão de Alimentos , Teste de Esforço , Humanos , Masculino , Antissépticos Bucais/metabolismo , Fatores de Tempo , Resultado do Tratamento
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