312 research outputs found
Not Another Caffeine Effect on Sports Performance Study—Nothing New or More to Do?
The performance-enhancing potential of acute caffeine consumption is firmly established with benefits for many aspects of physical performance and cognitive function summarised in a number of meta-analyses. Despite this, there remains near exponential growth in research articles examining the ergogenic effects of caffeine. Many such studies are confirmatory of well-established ideas, and with a wealth of convincing evidence available, the value of further investigation may be questioned. However, several important knowledge gaps remain. As such, the purpose of this review is to summarise key knowledge gaps regarding the current understanding of the performance-enhancing effect of caffeine and justify their value for future investigation. The review will provide a particular focus on ten research priorities that will aid in the translation of caffeine’s ergogenic potential to real-world sporting scenarios. The discussion presented here is therefore essential in guiding the design of future work that will aid in progressing the current understanding of the effects of caffeine as a performance enhancer
Agreement between Force Platform and Smartphone Application-Derived Measures of Vertical Jump Height in Youth Grassroots Soccer Players
Given the importance of vertical jump assessments as a performance benchmarking tool, the assessment of neuromuscular function and indicator of health status, accurate assessment is essential. This study compared countermovement jump (CMJ) height assessed using MyJump2 (JHMJ) to force-platform-derived jump height calculated from time in the air (JHTIA) and take-off velocity (JHTOV) in youth grassroots soccer players. Thirty participants (Age: 8.7 ± 0.42 yrs; 9 females) completed bilateral CMJs on force platforms whilst jump height was simultaneously evaluated using MyJump2. Intraclass correlation coefficients (ICC), Standard error of measurement (SEM), coefficient of variance (CV) and Bland–Altman analysis were used to compare performance of MyJump2 to force-platform-derived measures of CMJ height. The median jump height was 15.5 cm. Despite a high level of agreement between JHTIA and JHTOV (ICC = 0.955), CV (6.6%), mean bias (1.33 ± 1.62 cm) and 95% limits of agreement (LoA −1.85–4.51 cm) were greater than in other comparisons. JHMJ performed marginally better than JHTIA when compared to JHTOV (ICC = 0.971; 95% CI’s = 0.956–0.981; SEM = 0.3 cm; CV = 5.7%; mean bias = 0.36 ± 1.61 cm; LoA = −3.52–2.80 cm). Irrespective of method, jump height did not differ between males and females (p > 0.381; r TIA and JHMJ should be used with caution. JHTOV should be used to guarantee accuracy in the calculation of jump height
Determining and comparing the optimum power loads in hexagonal and straight bar deadlifts in novice strength-trained males
Effects of acute caffeine ingestion on the physical performance of amateur American football athletes
The aim of this study was to investigate the effects of acute caffeine ingestion (5 mg.kg-1) on jump, isometric strength and repeated sprint performance in amateur American football athletes. Twelve players (24.6 ± 3.66 years and 115.18 ± 24.35 kg of body weight) ingested a dose of caffeine (5 mg.kg−1) or placebo 60 min prior to a testing session consisting of: 1) countermovement jump (CMJ); 2) isometric mid-tight pull (IMTP); and 3) 3-line drills (200-yd shuttle runs with a 2-minute rest between sprints). Two testing sessions were performed using a double-blind, counterbalanced, crossover design during a pre-season training camp. Results indicated: Caffeine ingestion improved CMJ performance (p = 0.035), but no differences were observed on IMTP strength (p = 0.22) and line drill performance (total time: p = 0.65, and fatigue (%): p = 0.75) when compared to placebo condition. Conclusion: Acute caffeine ingestion improved jump performance, but not isometric strength and repeated sprint with change-of-direction performance in amateur American Football athletes
Heart rate dynamics in heart transplantation patients during a treadmill cardiopulmonary exercise test: A pilot study
Background: One way of defining an individual’s heart effort is to calculate the maximum
heart rate to be expected given their age, but the reinnervation seen in patients who have
received heart transplants makes for different calculations from patients who have suffered
heart failure. The purpose of this study is to evaluate heart rate dynamics (rest, peak and
percentage of predicted heart rate for age) in heart transplant patients compared to optimized
beta-blocked heart failure patients during a treadmill cardiopulmonary exercise test.
Methods: Twenty two (81% male, 46 ± 12 years) sedentary heart failure patients and
15 (47% male, 44 ± 13 years) sedentary heart transplant patients performed a treadmill
cardiopulmonary exercise test between 10 am and 3 pm. Heart failure optimization was considered
50 mg/day or more of carvedilol, with a resting heart rate of between 50 and 60 bpm.
Results: Basal heart rate was lower in heart failure patients (58 ± 5 bpm) compared to heart
transplant patients (93 ± 11 bpm; p < 0.0001). Similarly, the peak heart rate (percentage of
the maximum predicted for age) was lower in heart failure patients (60 ± 13%) compared to
heart transplant patients (80 ± 12; p < 0.0001). Maximum respiratory exchange ratio did not
differ between the groups (1.05 ± 0.06 in heart failure patients and 1.11 ± 0.1 in heart
transplant patients; p = 0.08). Moreover, the heart rate reserve between heart failure (49 ± 22)
and heart transplantation (46 ± 16%) was not different (p = 0.644).
Conclusions: No patient reached the maximum heart rate predicted for their age during
a treadmill cardiopulmonary exercise test. The heart rate reserve was similar between groups.
A heart rate increase in heart transplant patients during cardiopulmonary exercise test of
more than 80% of the maximum age-adjusted value should be considered an effort near the
maximum
Effect of Caffeine Ingestion on Indirect Markers of Exercise-Induced Muscle Damage: A Systematic Review of Human Trials
The effect of caffeine on mitigating exercise-induced muscle damage (EIMD) is still poorly understood, but it was hypothesized that caffeine could contribute to decreasing delayed onset muscle soreness, attenuating temporary loss of strength, and reducing circulating levels of blood markers of muscle damage. However, evidence is not conclusive and beneficial effects of caffeine ingestion on EIMD are not always observed. Factors, such as the type of exercise that induces muscle damage, supplementation protocol, and type of marker analyzed contribute to the differences between the studies. To expand knowledge on the role of caffeine supplementation in EIMD, this systematic review aimed to investigate the effect of caffeine supplementation on different markers of muscle damage. Fourteen studies were included, evaluating the effect of caffeine on indirect muscle damage markers, including blood markers (nine studies), pain perception (six studies), and MVC maximal voluntary contraction force (four studies). It was observed in four studies that repeated administration of caffeine between 24 and 72 h after muscle damage can attenuate the perception of pain in magnitudes ranging from 3.9% to 26%. The use of a single dose of caffeine pre-exercise (five studies) or post-exercise (one study) did not alter the circulating blood levels of creatine kinase (CK). Caffeine supplementation appears to attenuate pain perception, but this does not appear to be related to an attenuation of EIMD, per se. Furthermore, the effect of caffeine supplementation after muscle damage on strength recovery remains inconclusive due to the low number of studies found (four studies) and controversial results for both dynamic and isometric strength tests
A INSERÇÃO DE MATERIAIS RECICLÁVEIS NA ESTRUTURA DE PAVIMENTOS RODOVIÁRIOS E VIAS URBANAS
Atualmente vem crescendo o uso de automóveis e ciclomotores para o transporte individual ou coletivo, para que haja a utilização de forma satisfatória fez-se necessário a criação de superfícies em que os mesmos possam transitar com segurança e se relacionando com todos os componentes da cidade, havendo a presença de pedestres e ciclistas. A pavimentação é de suma importância para sociedade, a mesma possibilita a locomoção e o deslocamento de pessoas e materiais que movimentam a economia de uma cidade. Métodos e materiais utilizados na construção de rodovias são estudados constantemente para que a vida útil das vias seja de grande duração e que haja o desempenho eficaz de acordo com a sua utilização. Assim as camadas constituintes de um pavimento sendo rígido, semirrígido ou flexível, devem dispor de características a todos os esforços que são solicitados e também as temperaturas que nelas atuam. Então neste estudo foi abordado a definição de pavimentação, necessidades, características e a de inserção de novos materiais recicláveis na estrutura de pavimentos. Concluiu-se que diversas fontes renováveis agregam valores a pavimentação, possibilitando a reutilização de materiais que iriam ser descartados e que apresentam características similares ou melhores do que as utilizadas comumente
The Effects of Physical Fitness on Postactivation Potentiation in Professional Soccer Athletes
POLUIÇÃO VISUAL NA CIDADE DE MANAUS
O objetivo desta pesquisa foi o de analisar os impactos da poluição visual na cidade de Manaus, destacando sua relação com o meio ambiente equilibrado e seu tratamento penal. A metodologia utilizada nesta pesquisa foi a do método dedutivo; quanto aos meios a pesquisa foi bibliografica e quanto aos fins, qualitativa. Concluiu-se que a cidade de Manaus, embora esteja situada na maior floresta tropical do planeta, encontra-se em um processo de devastação sem controle, com ausência de vegetação natural urbana, o que acarreta um meio ambiente urbano rodeado de uma selva de uma pedra visualmente desequilibrada
- …