Effect of acute ingestion of β-hydroxybutyrate salts on the response to graded exercise in trained cyclists

Acute ingestion of ketone salts induces nutritional ketosis by elevating β-hydroxybutyrate (βHB), but few studies have examined the metabolic effects of ingestion prior to exercise. Nineteen trained cyclists (12 male, 7 female) undertook graded exercise (8 min each at ～30%, 40%, 50%, 60%, 70%, and 80% VO_2peak) on a cycle ergometer on two occasions separated by either 7 or 14 days. Trials included ingestion of boluses of either (i) plain water (3.8?mL?kg?body mass^?1) (CON) or (ii) βHB salts (0.38?g?kg?body mass^?1) in plain water (3.8?mL?kg body mass^?1) (KET), at both 60 min and 15 min prior to exercise. During KET, plasma [βHB] increased to 0.33?±?0.16?mM prior to exercise and 0.44?±?0.15?mM at the end of exercise (both p?.05). Plasma glucose was 0.44?±?0.27?mM lower (p?.01) 30?min after ingestion of KET and remained ～0.2?mM lower throughout exercise compared to CON (p?.001). Respiratory exchange ratio (RER) was higher during KET compared to CON (p?.001) and 0.03–0.04 higher from 30%VO_2peak to 60%VO_2peak (all p?.05). No differences in plasma lactate, rate of perceived exertion, or gross or delta efficiency were observed between trials. Gastrointestinal symptoms were reported in 13 out of 19 participants during KET. Acute ingestion of βHB salts induces nutritional ketosis and alters the metabolic response to exercise in trained cyclists. Elevated RER during KET may be indicative of increased ketone body oxidation during exercise, but at the plasma βHB concentrations achieved, ingestion of βHB salts does not affect lactate appearance, perceived exertion, or muscular efficiency.     

Comparison of different regression models to fit the force–velocity relationship of a knee extension exercise

The aims of this study were to compare the goodness of fit and the concurrent validity of three regression models of the force–velocity relationship in a unilateral knee extension exercise. The force–velocity relationship and the one-repetition-maximum load in the dominant and non-dominant leg were obtained in 24 male sports sciences students by a progressive protocol. Additionally, the maximum voluntary contraction (MVC) of the knee extensor muscles was recorded. Individual force–velocity relationships were obtained by the linear, quadratic polynomial and exponential regression models. Although the adjusted coefficients of determination of all three models were high, the polynomial model’s coefficient was slightly but significantly higher than the rest of the models (p < 0.05), while the standard error of estimate was slightly higher for the linear than for polynomial model (p = 0.001). MVC was underestimated by F ₀ calculated from the linear and polynomial models, while the maximum power was accurately estimated by the linear model. In summary, while the polynomial model revealed somewhat better fit, the linear model more accurately estimates the maximum power and provides the parameters of apparent physiological meaning. Therefore, we recommend using the linear model in research and routine testing of mechanical capacities of knee extensors.     

Quantifying the effect of sponsor awareness and image on the sports involvement–purchase intention relationship

Despite the exponential growth of corporate expenditure on sponsorship, to date there has been little exploration of the degree to which sports involvement influences purchase intention of sponsor products and how much of this effect can actually be ascribed to an indirect effect through sponsor image and sponsor awareness. Using a multiple mediation model, this research explored the mediational role of sponsor awareness and sponsor image in the sports involvement–purchase intention relationship. Results revealed that while sponsor image is an effective mediator of the sports involvement and purchase intention relationship, sponsor awareness acts as a suppressor. Moreover, per the ratio of indirect effect to total effect, sponsor image accounts for 90% of the total effect of sports involvement on purchase intention. These findings should assist sponsors and sport event managers to capitalize on sponsorship opportunities more effectively.     

Understanding implementation and change in complex interventions. From single- to multi-methodological research on the promotion of youths’ participation in physical education

Abstract

Existing studies on complex interventions aiming to promote youths’ participation in physical education (PE) appear to be predominantly single-methodological. The aim of this article is to examine the benefits and challenges of evaluating an intervention to increase youths’ participation and experiences of social inclusion in the PE context using a multi-method approach integrating quantitative and qualitative approaches. The multi-method approach allowed an integration of the findings with regard to the implementation as well as the effect of the intervention. First of all, standardized questionnaires provided a manipulation check of the delivery of the intervention, while qualitative observations and interviews identified the diversity in pupils’ reactions thereto. Secondly, quantitative findings on the effect of the intervention were related to qualitative findings pointing to ambiguities in the pupils’ observed behaviour and interview responses. Thus, a more complete understanding of the implementation processes and effect of the intervention developed.     

Teachers in school sports: between the fields of education and sport?

According to the cultural sociologist Pierre Bourdieu, gaining access to a social space or a position within a social space requires a specific capital. For teachers, this is normally indicated by a valid teaching certificate with relevant subject knowledge. However, when no qualified teachers are available, which is the case for the subject of school sports in Sweden, other assets gain recognition. Drawing on Bourdieu's conceptual framework, this paper examined the conditions for school sports in Sweden, and based on questionnaires answered by 109 teachers, explored the competencies, education and backgrounds teachers in upper secondary school sports possess. The paper address the question: what valuable resources are required to become a teacher of school sports and gain recognition as symbolic capital? The results show that while school sports in Sweden are carried out through a school subject and thus regulated by the government, it is influenced by both the fields of education and sport. Furthermore, the questionnaire results show that a majority of the teachers are employed as coaches instead of teachers and that less than half of them (45%) have a teacher education background, while 95% have a coaching education background. However, the results also show that teachers assessed their competencies for teaching school sports as high, especially with regard to competencies in specific sport skills. In conclusion, this paper shows how coaching education and experience in competitive sports are an important resource required to become a teacher in school sports and is thus recognized as symbolic capital. Therefore, school sports cannot be viewed as a legitimate part of the field of education but can be viewed as a part of the field of sport.     

Motor adaptation in complex sports – The influence of visual context information on the adaptation of the three-point shot to altered task demands in expert basketball players

Abstract

We examined the influence of visual context information on skilled motor behaviour and motor adaptation in basketball. The rules of basketball in Europe have recently changed, such that that the distance for three-point shots increased from 6.25 m to 6.75 m. As such, we tested the extent to which basketball experts can adapt to the longer distance when a) only the unfamiliar, new three-point line was provided as floor markings (NL group), or b) the familiar, old three-point line was provided in addition to the new floor markings (OL group). In the present study 20 expert basketball players performed 40 three-point shots from 6.25 m and 40 shots from 6.75 m. We assessed the percentage of hits and analysed the landing position of the ball. Results showed better adaptation of throwing performance to the longer distance when the old three-point line was provided as a visual landmark, compared to when only the new three-point line was provided. We hypothesise that the three-point line delivered relevant information needed to successfully adapt to the greater distance in the OL group, whereas it disturbed performance and ability to adapt in the NL group. The importance of visual landmarks on motor adaptation in basketball throwing is discussed relative to the influence of other information sources (i.e. angle of elevation relative to the basket) and sport practice.     

A coaches’ perspective on the contribution of anthropometry,physical performance,and motor coordination in racquet sports

ABSTRACT

Differences and similarities between table tennis and other racquet sports exist, but are not well documented in the literature, in spite of the relevance for talent identification. In this study we aimed at identifying the key characteristics of table tennis in comparison with tennis and badminton based upon a survey in coaches. A total of 177 licensed coaches from all across the world and with diverse professional backgrounds completed a survey on anthropometric measures, physical performance, and motor coordination skills. On a scale from 1 to 10, coaches indicated to what extent a talent characteristic was important for their sport. MANOVA identified key differences as well as similarities between all three racquet sports and a subsequent discriminant analysis allocated coaches correctly for table tennis, tennis, and badminton 81.01%, 55.6%, and 71.4% respectively. Our results show that table tennis and other racquet sport coaches are well aware of differences between the racquet sports and also the importance and value of testing and assortment of skill components. These findings can assist coaches in future talent orientation and transfer in racquet sports.     

Brief Discussion on the functions of sports vocational college libraries in athletes＇ cultural education

运动员学生因为经常性的比赛训练,文化学习的时间受到影响,根据这种情况,可以采用机动、主动学习的方法,随着信息技术的发展,学习方式的改变,发挥图书馆具有的丰富资源的优势,为运动员的文化教育和素质教育服务,为运动员综合素质的提高提供更为便利的条件,体育高职院校的图书馆在运动员的文化教育中发挥着重要作用。     

What must I know to be brave?: revisiting the role of knowledge in the exercise of courage in sport

The Platonic definition of courage as the ‘knowledge of the fearful and the hopeful’ is often eschewed by philosophers of sport. In fact, the passionate nature of sport itself seems to testify against such a definition. Hence, accounts of courage within sport tend to emphasize the affective dimension of courage at the expense of the cognitive dimension. This essay argues in defense of the Platonic vision of courage as a species of knowledge as opposed to contemporary attempts to recover the affective dimension of courage, as exemplified by John Corlett. I shall argue that far from producing an overly intellectualized vision of courage, treating courage as a species of knowledge, even within sport, throws valuable light on the exercise of courage in sport and on the shape of sport itself with regards to the exercise of virtue.     

From Fixed Capacities to Performance-Enhancement: The Paradigm Shift in the Science of ‘Training’ and the Use of Performance-Enhancing Substances

The use of performance-enhancing substances fundamentally rests on a particular, historically situated, ontology of human performance. By analysing ‘training’ in the nineteenth and twentieth centuries, we examine the powerfully influential ontology that frames substance use today. Rooted in the first law of thermodynamics, an ontology of fixed human capacities dominated until the mid-twentieth century. Training entailed ‘drill’ to refine technique, coordination and precision. Although physiologists showed exercise increased strength and endurance, it was not until the cold war period that the paradigm shift to ‘performance capacities’ occurred. Track, weight lifting and cycling provide examples of how and why this happened.     

Who's joining the club? Participation of socially vulnerable children and adolescents in club-organised sports

Sport is often considered as a promising instrument for reaching a wide array of policy objectives. Social inclusion is one of the goals frequently mentioned. Though one can argue about the feasibility of the many claims made, sport can only reasonably be expected to play a role if the targeted population is effectively taking part in sports. This is what is investigated in this study. The focus lies on the sports participation of children (primary school) and adolescents (secondary school), more particularly in a club-organised setting. The purpose of this study is to investigate whether family related factors associated with a higher risk for social exclusion can be considered as determinants of club sport participation among children and adolescents. Data are based on a large-scale cross-sectional survey (2009), collected in 39 schools in Flanders (Belgium), with a total of 3005 children and adolescents (aged 6–18) participating in the research. A multilevel logistic regression has been conducted, controlling also for differences between schools. Income poverty and parental education come forward as important determinants for club-organised sports participation. No evidence was found that living in a single parent-household affects the likelihood of club-organised sports participation. While sport is often considered as an important instrument for social inclusion, the study shows that children and adolescents who are likely to occupy a more vulnerable position in society as a whole, have higher odds to be left out with regard to sport club participation as well.     

Animal exercise studies in cardiovascular research: Current knowledge and optimal design—A position paper of the Committee on Cardiac Rehabilitation,Chinese Medical Doctors’ Association

Growing evidence has demonstrated exercise as an effective way to promote cardiovascular health and protect against cardiovascular diseases However, the underlying mechanisms of the beneficial effects of exercise have yet to be elucidated. Animal exercise studies are widely used to investigate the key mechanisms of exercise-induced cardiovascular protection. However, standardized procedures and well-established evaluation indicators for animal exercise models are needed to guide researchers in carrying out effective, high-quality animal studies using exercise to prevent and treat cardiovascular diseases. In our review, we present the commonly used animal exercise models in cardiovascular research and propose a set of standard procedures for exercise training, emphasizing the appropriate measurements and analysis in these chronic exercise models. We also provide recommendations for optimal design of animal exercise studies in cardiovascular research, including the choice of exercise models, control of exercise protocols, exercise at different stages of disease, and other considerations, such as age, sex, and genetic background. We hope that this position paper will promote basic research on exercise-induced cardiovascular protection and pave the way for successful translation of exercise studies from bench to bedside in the prevention and treatment of cardiovascular diseases.