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The use of data and analytics in professional football organisations has grown steadily over the last decade. Nevertheless, how and whether these advances in sports analytics address the needs of professional football remain unexplored. Practitioners from national federations qualified for the FIFA World Cup Qatar 2022™ and professional football clubs from an international community of practitioners took part in a survey exploring the characteristics of their data analytics infrastructure, their role, and their value for elaborating player monitoring and positional data. Respondents from 29 national federations and 32 professional clubs completed the survey, with response rates of 90.6% and 77.1%, respectively. Summary information highlighted the underemployment of staff with expertise in applied data analytics across organisations. Perceptions regarding analytical capabilities and data governance framework were heterogenous, particularly in the case of national federations. Only a third of national federation respondents (~30%) perceived information on positional data from international sports data analytics providers to be sufficiently clear. The general resourcing limitations, the overall lack of expertise in data analytics methods, and the absence of operational taxonomies for reference performance metrics pose constraints to meaningful knowledge translations from raw data in professional football organisations.

L’ouvrage présente avec clarté et précision les différents aspects de la propulsion anaérobie. Il s'adresse aux étudiants en formation initiale d'ingénieurs et de master ou complémentaire dans un cycle doctoral.L’exposé reprend d’abord les concepts de base en mettant l'accent sur les points clefs en relation avec la propulsion aéronautique. Les concepts développés doivent permettre au futur ingénieur de comprendre les aspects qui prévalent à la conception et au calcul des performances des fusées. Il s’agit de l’architecture des fusées et des fluides (ergols liquides ou propergols solides). Ces concepts sont fondés sur la thermodynamique des systèmes réactifs, dont les lois générales sont rappelées, ainsi que les lois de la dynamique des fluides relatives aux écoulements dans les tuyères.Les auteurs font de nombreuses références à des systèmes propulsifs actuellement mis en œuvre dans le monde et plus spécifiquement aux USA et en Europe.Les outils numériques et les concepts présentés permettront au lecteur de réaliser des avant-projets réalistes, préalables aux développements technologiques ultérieurs.

The aim of this cross-sectional study was to compare dietary intake to published recommendations and to analyze the potential relationship between body composition and dietary intake in collegiate athletes. Eighteen healthy male middle- and long-distance runners (age 20.11 ± 2.72 y; height, 174.7 ± 6.1 cm; body mass, 64.0 ± 7.7 kg), were recruited from a Mexican university track and field team at the beginning of the general preparation phase for national competitions. Participants completed three 24-hour dietary recalls, which were used to estimate dietary intake. Body composition was measured by Dual-energy X-ray absorptiometry (DXA). Athletes displayed high body fat values. Protein intake was significantly higher than published recommendations. Iron, zinc, sodium, and vitamin C intake were significantly higher than recommended values, while potassium and calcium intake were below established recommendations. No significant correlations between body composition variables (i.e body fat, lean body mass, bone mineral content) and dietary intake (i.e energy, macronutrients and selected vitamins and minerals) could be found. These findings suggest that coaches and practitioners should pay close attention to dietary intake and body composition of endurance athletes starting general preparation for competition. Future studies on changes of dietary intake and body composition during off-season and competitive phase, which also track physical activity, are warranted., El objetivo de este estudio transversal fue comparar la ingesta dietética con las recomendaciones publicadas y analizar la relación potencial entre la composición corporal y la ingesta dietética en corredores universitarios. Dieciocho atletas masculinos sanos de media y larga distancia (edad 20,11 ± 2,72 años; altura, 174,7 ± 6,1 cm; masa corporal, 64,0 ± 7,7 kg), fueron reclutados de un equipo de atletismo de una universidad mexicana al comienzo de la fase de preparación general de competiciones nacionales. Los participantes completaron tres recordatorios dietéticos de 24 horas, que se utilizaron para estimar la ingesta dietética. La composición corporal se midió mediante absorciometría de rayos X de energía dual (DXA). Los atletas mostraron altos valores de grasa corporal. La ingesta de proteínas fue significativamente mayor que las recomendaciones publicadas. La ingesta de hierro, zinc, sodio y vitamina C fue significativamente superior a los valores recomendados, mientras que la ingesta de potasio y calcio estuvo por debajo de las recomendaciones establecidas. No se encontraron correlaciones significativas entre las variables de composición corporal (es decir, grasa corporal, masa corporal magra, contenido mineral óseo) y la ingesta dietética (es decir, energía, macronutrientes y vitaminas y minerales seleccionados). Estos hallazgos sugieren que los entrenadores y los practicantes deberían prestar mucha atención a la ingesta dietética y la composición corporal de los atletas de resistencia que comienzan la preparación general para la competencia. Se justifican estudios futuros sobre los cambios en la ingesta dietética y la composición corporal durante la fase fuera de temporada y competitiva, como también un seguimiento de la actividad física.

Background: Reference values of body fat for competitive volleyball players are lacking, making it difficult to interpret measurement results. This review systematically summarized published data on the relative body fat of volleyball players and calculated potential differences between sex, measurement method, and competitive level. Methods: The protocol followed the Preferred Reported Items for Systematic Reviews and Meta-Analysis guidelines. The literature search was conducted using five electronic databases to retrieve all relevant publications from January 1, 2010, to July 1, 2021. The 63 studies including 2607 players that met the inclusion criteria were analyzed using random-effects models. Data were reported as pooled mean body fat with 95% confidence intervals. Results: Body fat for males and females was 12.8% (11.9–13.8%) and 22.8% (21.9–23.7%), respectively. Body fat was 18.3% (16.3–20.4%) measured via skinfolds, 18.4% (15.6–21.2%) via bioelectrical impedance analysis, 24.2% (20.4–28.0%) via dual-energy x-ray absorptiometry and 21.6% (17.4–25.8%) via densitometry. Regional, national, and international-level players had body fat values of 19.5% (17.8–21.2%), 20.3% (18.6–22.0%), and 17.9% (15.7–20.4%), respectively. When the meta-regression was adjusted for the variables sex, measurement method, and competitive level, a significant difference between sex (p < 0.001), dual-energy x-ray absorptiometry and skinfolds (p = 0.02), and national and international-level players (p = 0.02) was found. However, sensitivity analysis revealed that findings regarding measurement method and competitive level were not robust and should, therefore, be interpreted with caution. Conclusions: Despite the limitations of published data, this meta-analysis provided pooled values for body fat of male and female volleyball players for different competitive levels and measurement methods.

The purpose of this review was to systematically summarize studies measuring the body composition of competitive bodybuilding athletes to provide recommended values for preparation and during competition. The protocol was preregistered with PROSPERO (CRD42020197921) and followed the guidelines of the Preferred Reported Items for Systematic Reviews and Meta-Analysis. A search of 5 electronic databases (PubMed, Web of Science, SportDiscus, CINAHL, and Scopus) was conducted to retrieve all relevant publications from January 1, 2000, up to June 13, 2021. Of 16 studies meeting the inclusion criteria, 6 presented longitudinal data on competition preparation and were discussed in detail. In the general preparation phase, body fat levels of bodybuilding athletes ranged between 15.3 and 25.2% (female) and from 9.6 to 16.3% (male). Close to competition, however, body fat levels were substantially lower, ranging from 8.1 to 18.3% for female and 5.8–10.7% for male athletes. All studies comparing relative body fat values at various time points during competition preparation found significant reductions between 30 and 60% in relative body fat, whereas lean mass was mostly maintained. Findings from the studies included in this review suggest that most bodybuilding competitors keep resistance training volume high while increasing aerobic training volume when preparing for competition. Findings on energy intake and macronutrient distribution were unclear and should be addressed in future studies. Further research, especially on contest preparation, is warranted and should include more details about training programs, nutritional strategies, psychosocial situation, anabolic androgen steroid, and supplement use as well as measurement protocols and preparation.