Search results

Caffeine is a popular ergogenic aid, but its effects on swimming performance are not yet fully clear. Therefore, the purpose of this paper is to examine the effects of caffeine on swimming performance.

Crossover placebo-controlled studies that explored the effects of caffeine on swimming performance were included. Six databases were searched to find relevant studies with additional forward and backward citation tracking. The data were pooled in a random-effects meta-analysis.

Eight studies were included in the review. The main meta-analysis showed a significant ergogenic effect of caffeine ingestion on swimming performance (Cohen’s d: –0.20; 95% confidence interval: −0.32, −0.08; p = 0.0008; –1.7%). In the analysis for short-distance swimming events, caffeine ingestion had a significant ergogenic effect on swimming performance (Cohen’s d: –0.14; 95% confidence interval: –0.27, −0.01; p = 0.03; −1.4%). An ergogenic effect of caffeine was also found in the analysis for moderate-to-long swimming distance events (Cohen’s d: –0.36; 95% confidence interval: −0.67, −0.05; p = 0.02; −2.2%).

The present meta-analysis found that caffeine ingestion decreases the time needed to complete a given swimming event. While these ergogenic effects may be classified as small, they are likely important in swimming, where narrow margins commonly determine placings.

The purpose of this paper is to explore the effects of low doses of caffeine (<3 mg/kg) on jumping performance using a meta-analysis.

The search for eligible studies was performed through six databases, with additional backward and forward citation tracking. A random-effects meta-analysis was performed to compare the effects of caffeine vs placebo on jump height. The methodological quality of the included studies was appraised using the physiotherapy evidence database checklist.

Eight studies were included in the review. They were classified as good or excellent methodological quality. The pooled number of participants across all studies was 203. Four studies provided caffeine in relative doses, ranging from 1 to 2 mg/kg. Four studies provided caffeine supplementation in absolute doses of 80, 150 or 200 mg. The meta-analysis found that caffeine ingestion increased vertical jump height (Cohen’s d: 0.21; 95% confidence interval: 0.10, 0.31; p < 0.001; +3.5%).

The present meta-analysis found that caffeine doses of ∼1 to 2 mg/kg enhance jumping height. The effects observed herein are similar to those with higher caffeine doses, which is relevant as low caffeine doses produce minimal side effects. For most individuals, a caffeine dose of ∼1 to 2 mg/kg is equivalent to an amount of caffeine in an energy drink, one to two cups of coffee, one to two pieces of caffeinated chewing gum or several cups of green tea.

The purpose of this review is to provide a comprehensive summary of current research on the health risks and benefits associated with coffee drinking.

This review includes up‐to‐date information from the original literature on coffee drinking and health and presents findings in a manner accessible to both experts and non‐experts.

Coffee contains caffeine, antioxidants, and other phytochemicals, all of which affect disease risks. There is evidence that coffee drinking may not be suitable for certain individuals. Overall, however, coffee drinking seems to be a non‐harmful habit for those who drink it regularly and in moderation, and recent studies indeed suggest that it may even be beneficial for most people. The most currently available evidence suggests that coffee drinking can help reduce the risk of several diseases, most notably type 2 diabetes, Alzheimer's disease, and Parkinson's disease, although the underlying mechanisms for this effect are still being investigated.

Current studies suggest that coffee drinkers can help protect themselves from neurodegenerative and other diseases by drinking an average of two cups of regular, filtered coffee per day.

This article provides accessible and comprehensive information to researchers, nutritionists, and consumers who are interested in the potential health risks and benefits of regular and moderate coffee drinking.

The subject of nutrition and athletic performance is by no means a recent one. In those far off days of the first Olympic Games held in Greece from 776 BC‐400 AD the athlete was concerned with what he ate. The first competitor whose special diet we are told anything about was Charmis of Sparta. He was victor of the sprint race at the Games held in 668 BC and is known to have trained on a diet of dried figs. Tradition indicates that as a sprinter he found the extra sugar in fruit helpful. Later, Dromeus of Stymphalus, a trainer who won the long race in 460 and 456 BC introduced a ‘meat’ diet which rapidly became popular.

Over the last few years, sportsmen and women have begun to realise the potential role of nutrition in relation to improving performance. As sporting standards get higher and higher, competitors often experiment with new diets, protein supplements and megavitamin doses in an attempt to achieve the ‘competitive edge’. There is, however, no conclusive evidence that such practices do improve performance. The whole area of nutrition in sport is currently receiving much interest within the nutrition and dietetic profession. It was one of the major topics discussed at the recent annual conference of the British Dietetic Association and the Sports Nutrition Foundation has recently been established to provide a focal point for the professional development of all those involved in the field of sports nutrition.

The purpose of this paper is to analyse differences in sociodemographic and sporting characteristics, health-behaviours, and food intake of athletes using and not using nutritional supplements (NS).

High-performance Portuguese athletes from 13 sports completed a NS usage questionnaire, assessing information on sociodemographic (sex, age, height, weight, athlete’s, and parental education level), health-related (smoking, daily time of sleeping, walking, and sitting), and sporting (type, number of international performances, weekly hours of training and weekly hours of gym) characteristics; and a semi-quantitative food-frequency questionnaire (86 items), regarding the previous 12 months.

From the 241 athletes (66 per cent males, 13-37 years), 64 per cent reported NS use. Supplement usage was associated with age 18 years (odds ratio (OR) 2.57, 95 per cent; confidence interval (CI) 1.17-5.65), performing individual sports (OR 5.45, 95 per cent; CI 2.49-11.93) and > 2 h gym/week (OR 2.42, 95 per cent; CI 1.15-5.11), a higher consumption of meat (OR 2.83, 95 per cent; CI 1.36-5.90), eggs (OR 2.53, 95 per cent; CI 1.07-5.96), and yogurt (OR 2.24, 95 per cent; CI 1.08-4.62), and a lower intake of processed meat (OR 0.32, 95 per cent; CI 0.15-0.72), vegetable oils (OR 0.35, 95 per cent; CI 0.17-0.74), margarine (OR 0.37, 95 per cent; CI 0.18-0.76), chips (OR 0.22, 95 per cent; CI 0.10-0.48), and fast food (OR 0.42, 95 per cent; CI 0.19-0.91).

Athletes using NS had different characteristics from non-users, and seemed to have healthier and more sports-oriented food choices. Our findings may help sport and health professionals to identify an alleged or future NS user, enabling the development of a timely and self-directed supplement scheme.

The case for physical activity has been established through its impact on reduction in the risk of physical ill‐health such as coronary heart disease. However, there is increasing interest in its potential for a) treating and preventing mental illness and also b) the promotion of mental well‐being in the general public. The topic is now widely studied with over 30 published narrative or meta‐analytic reviews of research into the effect of exercise on constructs such as clinical or subclinical depression or anxiety, self‐esteem, affect and mood, resilience to stress, cognitive function or sleep. This paper provides a summary and appraisal of the evidence for the effect of exercise on mental health and addresses key issues that face the use of exercise as a medium for health promotion.

Offers a number of insights into the nature of spirituality in organizations and how employees can gain greater spirituality and purpose in their work. Specifically, proposes that a recent leadership theory, thought self‐leadership, can assist employees in influencing or leading themselves towards experiencing more spirituality in their organizational life.

The concept of “Thought Self‐Leadership” involves individual self‐influence through cognitive strategies that focus on self‐dialogue, mental imagery, beliefs and assumptions, and thought patterns. A plethora of studies from various fields including management, counseling psychology, sports psychology, education, and communication, address the effect of these Thought Self‐Leadership cognitive strategies on cognitions and behaviors. This research provides consistent support for the relationship between constructive self‐leadership of these cognitive processes and enhanced performance. The application of these cognitive strategies to the entrepreneurship domain, however, is sparse. We propose that the application of these principles to the entrepreneurial process offers the potential to enhance individual performance and mental states for both practicing and aspiring entrepreneurs. Propositions derived from the proposed framework are developed to serve as catalysts for empirically testing the applicability of Thought Self‐Leadership to the entrepreneurship context.

Despite the popularity and potential of self‐leadership strategies in modern organizations, no acceptably valid and reliable self‐leadership assessment scale has heretofore been developed. The present study tests the reliability and construct validity of a revised self‐leadership measurement scale created on the basis of existing measures of self‐leadership. Results from an exploratory factor analysis (EFA) demonstrate significantly better reliability and factor stability for the revised scale in comparison to existing instruments. Further, results from a confirmatory factor analysis (CFA) utilizing structural equation modeling techniques demonstrate superior fit for a higher order factor model of self‐leadership, thus providing evidence that the revised scale is measuring self‐leadership in a way that is harmonious with self‐leadership theory. Based on these results, the revised scale appears to be a reasonably reliable and valid instrument for the measurement of self‐leadership skills, behaviors, and cognitions. Implications for future empirical self‐leadership research are discussed.