1,720,962 research outputs found
Energy availability in athletes
Get PDFThis review updates and complements the review of energy balance and body composition in the Proceedings of the 2003 IOC Consensus Conference on Sports Nutrition. It argues that the concept of energy availability is more useful than the concept of energy balance for managing the diets of athletes. It then summarizes recent reports of the existence, aetiologies, and clinical consequences of low energy availability in athletes. This is followed by a review of recent research on the failure of appetite to increase ad libitum energy intake in compensation for exercise energy expenditure. The review closes by summarizing the implications of this research for managing the diets of athletes
Disordered eating and menstrual patterns in female university netball players
Get PDFObjectives: The primary aim of this study was to investigate disordered eating (DE) behavior and menstrual patterns in provincial-to-national level student netball players. The secondary aim was to examine the associations between body composition, energy intake, DE and menstrual patterns in student netball players. Methods: Twenty six Caucasian female netball players from a South African University volunteered to participate in this cross-sectional descriptive study. Height, weight and body composition were measured. Energy intake was assessed with 24-hour recalls and menstrual patterns were assessed with a menstrual history questionnaire. Players also completed an Eating Disorder Inventory (EDI) and an Eating Attitudes Test (EAT-26) to assess DE behavior. Results: Collectively 14 players (54.8%) were identified with DE behavior and scored above the designated cut-off score for the EAT-26 (≥20, n=3), the EDI Body Dissatisfaction subscale (EDI-BD) (≥14, n=7), the EDI Drive for Thinness subscale (EDI-DT) (≥15, n=3), and/or answered “Yes” (n=8) to DE behavioral questions. Eight players (30.8%) reported menstrual irregularities during the past 12 months of which four (15.4%) also reported secondary amenorrhea (absence of ≥3 consecutive menstrual cycles) during training. Five players (19.2%) presented with DE behavior, menstrual irregularity and primary and/or secondary amenorrhea. Reported energy intake was significantly lower in the players with menstrual irregularities and secondary amenorrhea compared to the remaining players (p less than 0.05). Conclusions: Top female student netball players may have suboptimal energy intakes and suffer from DE behavior, menstrual irregularities and secondary amenorrhea. Players and coaches should be aware of these risks and related health and performance consequences
Nutritional care of the elite child and adolescent athlete: Part I - Energy and nutrient needs
No full textNutritional care of the elite child and adolescent athlete: Part II: Special dietary issues and competition nutrition
No full textThis article (second of two parts) presents a review of literature and resources on special dietary issues and sport performance. Young athletes preparing for competition adopt various dietary plans. Those adopting a vegetarian diet should be screened for possible low energy and specific micronutrient (e.g Fe, Ca, vit B12) intakes which can be avoided with a well-balanced diet and appropriate supplementation. Vegetarianism has also been linked with disordered eating (DE). The prevalence of DE is rising amongst male athletes and black female athletes. Adolescent athletes are at great risk of developing DE due to dramatic life changes, increased vulnerability and low self-esteem during the adolescence period. Meal skipping, especially breakfast and unhealthy food choices are prominent in this group of athletes. Education and motivation regarding healthier and more nutrient dense food choices away from home is needed. Pre-event carbohydrate loading is not needed when an adequate carbohydrate-rich diet is followed. Low or high glycaemic index (GI) carbohydrate can be eaten pre-event. Fluids should be consumed regularly from one day pre-event to ensure euhydration. The ACSM recommends ingesting ~5-7ml.kg-1 slowly 4-hours pre-event. During long-term events as well as during the recovery period the ingestion of carbohydrate with high or medium GI at frequent intervals is promoted. To prevent voluntary dehydration regular ingestion of a flavoured carbohydrate-electrolyte drink is recommended at quantities individualized according to body weight losses surrounding the event
Caffeine Improves Triathlon Performance: A Field Study in Males and Females
No full textThe ergogenic effect of caffeine on endurance exercise is commonly accepted. We aimed to elucidate realistically the effect of caffeine on triathlon event performance using a field study design, while allowing investigation into potential mechanisms at play. A double-blind, randomized, crossover, field trial was conducted. Twenty-six triathletes (14 males, 12 females) participated (age: 37.8±10.6 years, habitual caffeine intake: 413±505 mg/day, percentage body fat: 14.5±7.2%, training/week: 12.8±4.5 hours). Microencapsulated caffeine (6 mg/kg body weight) was supplemented 60 minutes pre-trial. Performance data included time to completion (TTC), rating of perceived exertion (RPE) and profile of mood states (POMS). Blood samples taken before, during and post-race were analyzed for cortisol, testosterone and full blood count. Capillary blood lactate concentrations were assessed pre-race, during transitions and 3, 6, 9, 12, 15 minutes after triathlons. Caffeine supplementation resulted in a 3.7% reduction in swim time (33.5±7.0 vs. 34.8±8.1 minutes, p<0.05) and a 1.3% reduction in TTC (149.6±19.8 vs. 151.5±18.6 minutes, p<0.05) for the whole group. Gender differences and individual responses are also presented. Caffeine did not alter RPE significantly, but better performance after caffeine supplementation suggests a central effect resulting in greater overall exercise intensity at the same RPE. Caffeine supplementation was associated with higher post-exercise cortisol levels (665±200 vs. 543±169 nmol/l, p<0.0001) and facilitated greater peak blood lactate accumulation (ANOVA main effect, p<0.05). We recommend that triathlon athletes with relatively low habitual caffeine intake may ingest 6 mg/kg body weight caffeine, 45-60 minutes before the start of Olympic-distance triathlon in order to improve performance
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Evaluating a food supplement to optimise recovery post-exercise
No full textDSc (Dietetics), North-West University, Potchefstroom CampusMotivation. Super-compensation is the main principal in physical training aimed at
improving performance. It entails a catabolic process characterized by skeletal muscle
breakdown during exercise followed by and matched with an anabolic recovery process
post-exercise characterized by skeletal muscle adaptation and enhanced performance.
The recovery process is regarded as the most important phase of this principle, and
nutrition has been identified as a major contributor. Physiological recovery during the
post-exercise phase usually entails glycogen storage, as well as skeletal muscle repair
and adaptation. Increasing the rate of anabolism post-exercise or decreasing the rate of
catabolism during exercise could lead to speedy and effective recovery between training
sessions, especially with infrequent training sessions. It is thus clear that exercise has a
profound effect on skeletal muscle metabolism resulting in a simultaneous cycle of
muscle damage followed by repair, as well as glycogen depletion and storage.
Carbohydrates, protein and to a lesser extent fat, have been identified as contributors
towards enhanced recovery. By regulating the timing, amount, type and combination of
these nutrients ingested, anabolism post-exercise can be reached at an earlier stage
compared to unregulated ingestion of these nutrients. Various recommendations have
been established for the macronutrients in relation to post-exercise recovery. However,
the optimal ratio of dietary carbohydrate-to-protein for an increased rate of both glycogen
and muscle protein resynthesis, as well as the possible advantages of added amino
acids and/or metabolites to enhance this process remains to be elucidated. Little
research has been done on both glycogen and muscle protein re-synthesis when the
protein source in a dietary supplement is soy. Furthermore, data on the contribution of
the antioxidants in soy protein, especially is of lavones, in decreasing oxidative and DNA
damage incurred during and post-exercise, are limited. Designing a successful product
should also appeal to the acceptability and preference of the consumer. Thus,
evaluating a new product in terms of consumer acceptability, preference and
consumption intent could add positively to product development.
Objective. To develop a soy drink with effective glycaemic index, gastro-intestinal
tolerance, and sensory effects, as well as to evaluate it in terms of glycogen resynthesis,
skeletal muscle damage, oxidative response, and muscle soreness compared to a
carbohydrate drink.
drink was evaluated by 104 athletes (72M; 32F) post-exercise with a validated hedonic
questionnaire. ...Doctora
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