Academy of Nutrition and Dietetics: Revised 2021 Standards of Practice and Standards of Professional Performance for Registered Dietitian Nutritionists (Competent, Proficient, and Expert) in Sports and Human Performance Nutrition.

Nutrition in sports and human performance incorporates knowledge of the intersection of human physiology and nutrition. Registered dietitian nutritionist (RDN) practitioners in sports and human performance focus on nutrition care that is specific to the individual and their sport/occupational requirements. The Dietitians in Sports, Cardiovascular and Wellness Dietetic Practice Group, along with the Academy of Nutrition and Dietetics Quality Management Committee, have updated the Standards of Practice (SOP) and Standards of Professional Performance (SOPP) for RDNs working in sports and human performance. The SOP and SOPP for RDNs in Sports and Human Performance Nutrition provide indicators that describe three levels of practice: competent, proficient, and expert. The SOP uses the Nutrition Care Process and clinical workflow elements for delivering care to athletic/professional populations. The SOPP describes the following six domains that focus on professional performance: Quality in Practice, Competence and Accountability, Provision of Services, Application of Research, Communication and Application of Knowledge, and Utilization and Management of Resources. Specific indicators outlined in the SOP and SOPP depict how these standards apply to practice. The SOP and SOPP are complementary resources for RDNs and are intended to be used as a self-evaluation tool for assuring competent practice in sports and human performance and for determining potential education and training needs for advancement to a higher practice level in a variety of settings.

Decálogo de recomendaciones sobre psicología y deporte juvenil. Documento de consenso / Recommendations for psychology and youth sports. A consensus document

Las organizaciones deportivas involucradas en el deporte-base cuentan con entrenadores, directivos y árbitros cuya actitud, trabajo y dedicación permite deducir que la mayoría son ciudadanos voluntarios con escaso conocimiento sobre la psicología como método de trabajo. Este documento, impulsado por el Programa Talento Deportivo de la Universidad de Navarra y el Colegio Oficial de Psicólogos de Navarra, aborda el papel de la psicología en el deporte infanto-juvenil y los beneficios que puede aportar a deportistas, padres, entrenadores, árbitros o directivos. También establece un consenso en forma de decálogo y veintisiete recomendaciones con el objetivo de reconocer los beneficios de mejorar el conocimiento psicológico de los distintos perfiles implicados en el deporte-base con el fin de adquirir destrezas que beneficien tanto el rendimiento como el estado psicológico. Su objetivo es proveer unas directrices psicológicas para utilizarlas en el manejo y entrenamiento de los deportistas infanto-juveniles

Sports organisations involved in grassroots sports have trainers, managers and referees whose attitudes, work and dedication show that many of them are volunteers with little knowledge of psychology as a working method. This document, promoted by the Programa Talento Deportivo of the University of Navarra and the Official Association of Psychologists of Navarra, considers the role of psychology in children's and adolescents' sport and the benefits it can offer to sports players, parents, trainers, referees and managers. It also establishes a consensus in the form of a set of guidelines and twenty-seven recommendations. The aim of this consensus is to recognise the benefits of including psychology in the profiles involved in grassroots sport, to enable those involved to acquire skills that can help to improve performance and psychological states, promoting directives to be used when managing and training young sports players

Relación entre la velocidad aeróbica máxima continua e intermitente con el rendimiento del CrossFit ® WOD Karen en sujetos físicamente activos / Relationship of continuous and intermittent maximal aerobic speed to CrossFit ® WOD Karen performance in physically active subjects

Introducción: El CrossFit ® es actualmente la modalidad de entrenamiento funcional de alta intensidad de mayor difusión. No obstante, no existen investigaciones que relacionen la velocidad aérobica máxima continua (VAM-C) e intermitente (VAM-I) con el rendimiento en este entrenamiento. Objetivo: Determinar la relación entre la velocidad aérobica máxima continua e intermitente con el rendimiento del CrossFit ® WOD Karen en sujetos físicamente activos. Métodos: Participaron 14 hombres y 6 mujeres, en tres días se realizaron las pruebas con un intervalo de 24-48 horas entre ellos, la velocidad aérobica máxima continua se evaluó a través del test de carrera 20 metros o Course Navette, la velocidad aérobica máxima intermitente se valoró por medio del 30-15 ITF (Intermittent Fitness Test) y por último se midió el rendimiento del WOD CrossFit ® Karen (150 lanzamientos de balón medicinal a pared en el menor tiempo posible). Los datos obtenidos fueron analizados en el paquete estadístico PSPP con un nivel de confianza del 95 por ciento y un p-valor del 0,05. Resultados: Los resultados obtenidos presentaron distribución normal (p > 0,05) para ambos sexos salvo el tiempo del WOD CrossFit ® Karen en hombres (p < 0,05). El coeficiente de correlación sugiere que la velocidad aérobica máxima continua obtuvo una relación grande (r = -0,61) en mujeres y moderada en hombres (r = -0,44), mientras que la velocidad aérobica máxima intermitente presentó una asociación muy grande en mujeres (r = -0,76) y hombres (r = -0,78), pero solamente significativo con la velocidad aérobica máxima intermitente en hombres (p < 0,01). Conclusión: Una mayor aptitud física aeróbica intermitente es más influyente en el rendimiento del CrossFit ® WOD Karen en sujetos físicamente activos(AU)

Introduction: CrossFit® is at present the most widely known high-intensity functional training exercise program. However, no studies are available describing the relationship of continuous maximal aerobic speed (MAS-C) and intermittent maximal aerobic speed (MAS-I) to performance in this training mode. Objective: Determine the relationship of continuous and intermittent maximal aerobic speed to CrossFit® WOD Karen performance in physically active subjects. Methods: Fourteen men and six women participated in the study. The tests were performed in three days with a 24-48 hours separation between them. Continuous maximal aerobic speed was evaluated with the 20-m shuttle run test or Course Navette test and intermittent maximal aerobic speed with the 30-15 ITF (Intermittent Fitness Test). Finally, performance of the CrossFit® WOD Karen program was assessed through 150 medicine ball throws to the wall in as little time as possible. The data obtained were analyzed with the PSPP statistical package, using a confidence level of 95 percent and a p-value of 0,05. Results: The results obtained show a normal distribution (p > 0,05) for both sexes, except for CrossFit® WOD Karen time in men (p < 0,05). The correlation coefficient suggests that continuous maximal aerobic speed exhibited a high association in women (r = -0,61) and a moderate association in men (r = -0,44), whereas intermittent maximum aerobic speed exhibited a very high association in women (r = -0,76) and men (r = -0,78), but was only significant with intermittent maximum aerobic speed in men (p < 0,01). Conclusion: A better intermittent aerobic physical aptitude is more influential on CrossFit® WOD Karen performance in physically active subjects(AU)

Participation in pre-injury level sport one-year following sport-related concussion: A prospective, matched cohort study.

OBJECTIVES: To estimate the times taken to receive clearance to return to sporting activity and to return to pre-injury level of sport competition following sport-related concussion, and to estimate the proportion of athletes who were participating at their pre-injury level of sport competition six months and one-year following sport-related concussion. DESIGN: Prospective cohort study. METHODS: Amateur, adult athletes (16-38 years old) were diagnosed with sport-related concussion at a university-affiliated hospital emergency department. Participants were assessed within one-week, upon medical clearance to return to sporting activity, two weeks following return to sporting activity, six months, and 12 months following sport-related concussion. We assessed sex-, age-, and activity-matched non-injured, control participants at matched time-points. Participants were asked during each study assessment whether they were participating in any sport, in a different sport than before their sport-related concussion, in the same sport but at a lower level of competition than before their sport-related concussion, or in the same sport at the same level of competition than before their sport-related concussion. RESULTS: Fifty concussed participants and 50 non-injured, control participants completed the study. The median times taken to receive clearance to return to sporting activity and to return to pre-injury level of sport competition following sport-related concussion were 13 days (95%CI=12,16) and 31 days (95%CI=28,32), respectively. One-year following sport-related concussion, 52% of participants reported that they were no longer participating in the same sport and at the same level of competition as they were before their sport-related concussion, compared with only 24% of participants in the non-injured, control group (p=0.003). CONCLUSIONS: A greater percentage of athletes in the concussion group were not participating at their perceived pre-injury level of sport competition one-year following sport-related concussion compared with a non-injured control group. Factors that explain the lower proportion of amateur athletes participating at their pre-injury level of sport competition one-year after sport-related concussion are likely multifaceted and should be considered in future investigations.

Individual performance progression of German elite female and male middle-distance runners.

Current standards for talent identification often base on age-related cross-sectional or mixed data analyses. Longitudinal studies of elite runners from their very early to their late career are still rare, despite their need for valid talent identification and prognoses. Thus, we analysed individual performance trajectories of German international level middle-distance runners (30 females, 41 males) from an age of 14 until their top performance. Quadratic equations best fitted the individual performances from 14 years to late career in relation to the world record time. The individual trajectories were further used to construct a global performance progression model, providing annual performance estimates (mean and standard deviation of 800, 1000 and 1500 m race times in relation to the current world record time) of later top runners from early to late career. Our analysis implies that, on average, females started from a higher performance level at young age. In contrast, average performance progression of the males was higher until the age of 17 years. Performance peaked at an age of 24.0 ± 3.0 and 23.3 ± 2.6 years for the female and male runners, respectively. The provided average annual performance progressions, as well as their ranges, may help coaches and sport federations in their decision making on age-related performance criteria for talent identification in middle-distance running.

Citius, Altius, Fortius; Is It Enough to Achieve Success in Basketball?

The NBA Draft Combine includes a series of standardized measurements and drills that provide NBA teams with an opportunity to evaluate players. The purpose of this research was to identify the Combine tests that explain draft position and future performance in the NBA rookie season. Variables were selected from the previous categories of anthropometric measurements and strength and agility tests. A regression analysis was carried out. Combine variables, anthropometric and agility/strength variables were analyzed to explore their effect on draft position. Moreover, correlation analyses were performed to identify relationships among: (i) Combine anthropometric and strength and agility measures and game performance through game related statistics; and (ii) the draft position and game performance using Pearson's correlation coefficients. Results show that the Combine test does not predict draft position, with the exception of hand width and height in frontcourt players, and standard vertical jump and running vertical jump. Future performance indicators were explained by several Combine tests in all players.

Design and Validation of the Instrument for the Measurement of Learning and Performance in Football.

The assessment of tactical-technical knowledge of football is essential to develop optimal and integral teaching processes for students. Therefore, the aim of this study was to design and validate an instrument so that teachers, coaches, and researchers can observe and codify both the tactical behaviors and technical skills performed by the students in the game of football. The design and validation of the instrument were carried out in four phases: a) review of the literature and previous instruments; b) design of the Instrument for the Measurement of Learning and Performance in Football (IMLPFoot). It assesses all the offensive and defensive play actions, with and without the ball, as well as their three components (decision-making, technical execution, and final result); c) sample selection of experts (N = 12); and d) quantitative (Likert-type scale from 1 to 10) and qualitative assessment of degree the pertinence, unambiguity, and importance of each of the 33 items included in the IMLPFoot. Aiken's V coefficient was used to determine content validity. Likewise, internal consistency was calculated using Cronbach's α coefficient. The results showed demanding levels of validity (V ≥ 0.77), internal consistency (α = 0.983), inter-rater, and intra-rater reliability. Therefore, it is a valid and reliable instrument that makes possible a complete assessment of football in physical education classes and/or in the sports context (out-of-school football).

Assessing Technical Skills in Talented Youth Athletes: A Systematic Review.

BACKGROUND: Talent identification and development (TID) programs aim to identify players with the greatest potential for long-term success. Previous research suggests that the assessment of sport-specific technical skills is valuable for discriminating between more and less skilled individuals and/or for predicting future performance. OBJECTIVE: This review aims to provide an overview on both the instruments used to assess sport-specific technical skills and their discriminatory, explanatory and/or predictive findings in the context of TID. METHODS: Electronic searches were conducted in PubMed, Web of Knowledge, SPORTDiscus, SURF and Scopus (January 1990-October 2019). Search terms covered the areas of sport, technical skills assessment, performance, skill level and youth. In the end, 59 relevant studies were identified and evaluated. RESULTS: The results highlight the widespread and important role of technical skills in TID; almost all studies (93%) reported discriminatory, explanatory and/or predictive benefits for the assessment of sport-specific technical skills. Analyzing and categorizing the number of assessment methods applied in the studies (n = 69) according to their method type ('technique-related' or 'outcome-related' variables) and method set-up ('experimental' or 'competition' data acquisition environment) indicated a clear tendency towards 'outcome-related' (73%) and 'experimental' (75%) assessment methods. We also found a strong overrepresentation of studies assessing cross-sectional data (75%) in soccer (53%) in male samples (74% of studies reporting subjects' sex) from European countries (64%). CONCLUSIONS: On the one hand, our findings demonstrate the great capability of sport-specific technical skills assessments to discriminate different performance levels and predict future performance in TID activities. On the other hand, this review highlights the focus on 'outcome-related' and 'experimental' methods in specific populations and, consequently, the limited knowledge in other areas. Here, the application of 'technique-related' and 'competition' methods appears promising for adding new knowledge, especially in the light of technological advances.

Isokinetic back training is more effective than core stabilization training on pain intensity and sports performances in football players with chronic low back pain: A randomized controlled trial.

BACKGROUND: Isokinetic training (IKT) and core stabilization training (CST) are commonly used for balance training in musculoskeletal conditions. The knowledge about the effective implementation of these training protocols on sports performances in university football players with chronic low back pain (LBP) is lacking. OBJECTIVE: To find and compare the effects of IKT and CST on sports performances in university football players with chronic LBP. DESIGN: Randomized, double-blinded controlled study. SETTING: University hospital. PARTICIPANTS: Sixty LBP participants divided into isokinetic group (IKT; n = 20), core stabilization group (CST; n = 20), and the control group (n = 20) and received respected exercises for 4 weeks. OUTCOME MEASURES: Clinical (pain intensity and player wellness) and sports performances (40 m sprint, 4 × 5 m sprint, submaximal shuttle running, counter movement jump, and squat jump) scores were measured at baseline, after 4 weeks, 8 weeks, and 3 months. RESULTS: Four weeks following training IKT group shows more significant changes in pain intensity and player wellness scores than CST and control groups (P ≤ .001). Sports performance variables (40 m sprint, 4 × 5 m sprint, submaximal shuttle running, counter movement jump and squat jump) scores also show significant improvement in IKT group than the other 2 groups (P ≤ .001). CONCLUSION: This study suggests that training through IKT improves pain intensity and sports performances than CST in university football players with chronic LBP.

Critical speed and finite distance capacity: norms for athletic and non-athletic groups.

PURPOSE: Two parameters in particular span both health and performance; critical speed (CS) and finite distance capacity (D'). The purpose of the present study was to: (1) classify performance norms, (2) distinguish athletic from non-athletic individuals using the 3-min all-out test (3MT) for running, and (3) introduce a deterministic model highlighting the relationship between variables of the 3MT. METHODS: Athletic (n = 43) and non-athletic (n = 25) individuals participated in the study. All participants completed a treadmill graded exercise test (GXT) with verification bout and a 3MT on an outdoor sprinting track. RESULTS: Meaningful differences between non-athletic and athletic individuals (denoted by mean difference scores, p value and Cohen's d with 95% confidence intervals) were evident for CS (- 0.74 m s-1, p < 0.001, d = - 1.41 [1.97, - 0.87]), exponential growth time constant ([Formula: see text]; 2.75 s, p < 0.001, d = - 1.29 [- 1.45, - 0.42]), time to maximal speed ([Formula: see text]; - 2.80 s, p < 0.001, d = - 0.98 [- 1.51, - 0.47]), maximal speed ([Formula: see text]; - 1.36 m s-1, p < 0.001, d = - 1.56 [- 2.13, - 1.01]), gas exchange threshold (GET; - 5.62 ml kg-1 min-1, p < 0.001, d = - 0.97 [- 1.50, - 0.45]), distance covered in the first minute (1st min; - 81.69 m, p < 0.001, d = - 1.91 [- 2.52, - 1.33]), distance covered in the second minute (2nd min; - 52.02 m, p < 0.001, d = - 1.71 [- 2.30, - 1.15]) and maximal distance (- 153.78 m, p < 0.001, d = - 1.27 [- 1.82, - 0.74]). The correlation coefficient between key physiological and performance variables are shown in the form of a deterministic model created from the data derived from the 3MT. CONCLUSIONS: Coaches and clinicians may benefit from the use of normative data to potentially identify exceptional or irregular occurrences in 3MT performances.

Effect of Ten Weeks of Creatine Monohydrate Plus HMB Supplementation on Athletic Performance Tests in Elite Male Endurance Athletes.

Creatine monohydrate (CrM) and ß-hydroxy ß-methylbutyrate (HMB) are common ergogenic aids in the field of sports and are frequently used in an isolated way. However, there are a few studies that have investigated the effect of combining both supplements on different variables related to performance, with controversial results. Therefore, the main purpose of this study was to determine the efficacy and the degree of potentiation of 10 weeks of CrM plus HMB supplementation on sports performance, which was measured by an incremental test to exhaustion in elite male traditional rowers. In this placebo-controlled, double-blind trial, 10-week study, participants (n = 28) were randomized to a placebo group (PLG; n = 7), CrM group (0.04 g/kg/day of CrM; n = 7), HMB group (3 g/day of HMB; n = 7) and CrM-HMB group (0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before and after 10 weeks of different treatments, an incremental test was performed on a rowing ergometer to calculate the power that each rower obtained at the anaerobic threshold (WAT), and at 4 mmol (W4) and 8 mmol (W8) of blood lactate concentration. There were no significant differences in WAT and W4 among groups or in body composition. However, it was observed that the aerobic power achieved at W8 was significantly higher in the CrM-HMB group than in the PLG, CrM and HMB groups (p < 0.001; η2p = 0.766). Likewise, a synergistic effect of combined supplementation was found for the sum of the two supplements separately at WAT (CrM-HMBG = 403.19% vs. CrMG+HMBG = 337.52%), W4 (CrM-HMBG = 2736.17% vs. CrMG+HMBG = 1705.32%) and W8 (CrM-HMBG = 1293.4% vs. CrMG+HMBG = 877.56%). In summary, CrM plus HMB supplementation over 10 weeks showed a synergistic effect on aerobic power (measured as WAT, W4, and W8) during an incremental test but had no influence muscle mass.

Normative Reference Values for High School-Aged American Football Players.

McKay, BD, Miramonti, AA, Gillen, ZM, Leutzinger, TJ, Mendez, AI, Jenkins, NDM, and Cramer, JT. Normative reference values for high school-aged American football players. J Strength Cond Res 34(10): 2849-2856, 2020-The purpose of the present report was to provide test- and position-specific normative reference values for combine test results based on a large, nationally representative sample of high school-aged American football players in their freshman, sophomore, and junior classes. Cross-sectional anthropometric and performance data were obtained from 12 different high school American football recruiting combines between March 7, 2015, and January 9, 2016, across the United States. Subjects included a sample (n = 7,478) of high school-aged American football athletes in their junior (n = 3,779), sophomore (n = 2,514), and freshman (n = 1,185) classes. The database included combine date, school state, position, class, height, body mass (BM), 40-yard dash, pro-agility, 3-cone, vertical jump, broad jump, and power push-up. Each player self-classified their American football positions as defensive back, defensive end, defensive linemen, linebacker, offensive linemen, quarterback, running back, tight end (TE), or wide receiver. Test- and position-specific normative values were generated by aggregating data from freshman, sophomore, and junior classes. Mean differences were found among classes for all positions and all measurements (p ≤ 0.05), except for TE BM (p > 0.05). Greater differences for all variables were observed from freshman to sophomore classes than from sophomore to junior classes. These normative reference values may provide realistic comparisons and evaluations in performance for young American football players, parents, and coaches with collegiate football aspirations. High school strength and conditioning professionals should use these norms to set attainable goals and reward accomplishments for young football players.

Game-specific abilities in elite youth football players: validity and sensitivity to change of subjective coach ratings compared to objectively-assessed data.

BACKGROUND: Little is known on the accuracy of coaches' ratings of game-specific physical abilities in elite youth football players. The present study on elite youth football players aims to assess whether: 1) the coaches' subjective assessment of the level of performance of each athlete within the team is in accordance with objectively collected data; and 2) the coaches rate changes in the athletes' performance level accurately or not. METHODS: Data on jumping ability, sprinting speed, change of direction and strength were collected in seven age groups at a football youth academy (N.=150). The diagnostic battery was repeated after seven months (N.=138). Before the second session, the head coaches completed Likert-scaled closed questions on: 1) the importance of running speed and reactive strength components and their relevance to the individual game performance of each of their athletes; 2) the level of performance of their athletes; 3) the change between the first and second performance testing results. Validity and sensitivity of change of their ratings in comparison to the performance data were calculated using analyses of interrelationship. RESULTS: The data of the head coaches showed a low to medium effect size in the agreement with the performance data (Cohen's W=0.33-0.71). The evaluation of the change in level of performance was poorer (Cohen's W=0.04-0.2; not statistically significant). CONCLUSIONS: Our results underline that functional/physical testing twice during a season may be crucial for displaying performance levels of elite youth football players. Simple self-reported ratings by the coach may be valid in recent performance level assessment but not for performance changes.

Early Single Sport Specialization in a High-Achieving US Athlete Population: Comparing National Collegiate Athletic Association Student-Athletes and Undergraduate Students.

CONTEXT: Early single-sport specialization and the relative age effect are often cited as improving the chances of sport success. Both concepts suggest that genetics and the environment have little influence on sport success. OBJECTIVE: To compare National Collegiate Athletic Association Division I student-athletes (SAs) with their undergraduate nonathlete peers (NAs) in terms of birth month, age of sport initiation, and age of single-sport specialization. A family history of sport participation was examined as a potential marker for genetic and social influences. DESIGN: Cross-sectional survey. SETTING: Large urban university. PATIENTS OR OTHER PARTICIPANTS: A total of 273 Division I SAs (138 women, 135 men) and 155 NAs (78 women, 77 men) participated. The NAs had been involved in competitive youth sports before entering the university. MAIN OUTCOME MEASURE(S): Participants were asked to complete a questionnaire that addressed the age of sport initiation, birth month, age of single-sport specialization, and parental and sibling sport achievement. MAIN RESULTS: Neither birth month nor the age of sport initiation differed between groups (age of sport initiation = 7.16 ± 2.6 years for the SAs versus 7.71 ± 3.5 for the NAs; P = .176). A larger proportion of SAs began participating before 10 years of age (80% versus 63%; P = .02). The parents of SAs were more likely to have participated in collegiate (32.4% versus 8.4%; P < .0001) and professional (10.9% versus 1.3%; P = .0005) sports. The SAs specialized in a single sport at an older age (15.38 ± 2.7 years versus 14.30 ± 2.6 years; P = .002). Both groups participated in multiple sports in childhood (SAs = 3.9 ± 1.8 sports, NAs = 3.2 ± 1.8 sports; P = .366). CONCLUSIONS: The Division I SAs did not specialize in a single sport at a younger age than the NAs. No evidence of a relative age effect was present. Importantly, higher levels of sport achievement among the parents and siblings of SAs suggest that genetic endowment and family or other environmental dynamics play a large role in athletic performance. Overall, the results are not consistent with deliberate practice theory and point toward an alternative model that includes not only sport-specific skill development but also genetic and social factors as key elements of long-term sport achievement.

Optimizing running a race on a curved track.

In order to determine the optimal strategy to run a race on a curved track according to the lane number, we introduce a model based on differential equations for the velocity, the propulsive force and the anaerobic energy which takes into account the centrifugal force. This allows us to analyze numerically the different strategies according to the types of track since different designs of tracks lead to straights of different lengths. In particular, we find that the tracks with shorter straights lead to better performances, while the double bend track with the longest straight leads to the worst performances and the biggest difference between lanes. Then for a race with two runners, we introduce a psychological interaction: there is an attraction to follow someone just ahead, but after being overtaken, there is a delay before any benefit from this interaction occurs. We provide numerical simulations in different cases. Overall, the results agree with the IAAF rules for lane draws in competition, where the highest ranked athletes get the center lanes, the next ones the outside lanes, while the lowest ranked athletes get the inside lanes.

Qualities or skills discriminating under 19 rugby players by playing standards: a comparative analysis of elite, sub-elite and non-rugby players using the SCRuM test battery.

OBJECTIVE: Although schoolboy rugby is growing in popularity and played at different competitive levels in Zimbabwe, the influence of playing standard on qualities or skills of older male adolescent rugby players is unknown. Utilising a cross-sectional design, this study determined anthropometric, physiological characteristics and rugby-specific game skills defining elite under 19 (U19) schoolboy rugby players. Following development and subsequent assessment of test-retest reliability of School Clinical Rugby Measure (SCRuM) test battery, this study compared performance outcomes of elite rugby players (n = 41), sub-elite rugby players (n = 46) and non-rugby athletes (n = 26) to identify qualities or skills discriminating (i) elite from sub-elite and non-rugby players, and concomitantly (ii) sub-elite from non-rugby players. RESULTS: 40 m speed test (p < 0.001, ES = 1.78) and 2 kg Medicine Ball Chest Throw test (p < 0.001, ES = 1.69) significantly discriminated elite U19 from sub-elite and non-rugby players. These tests further differentiated sub-elite from non-rugby athletes. Additionally, 1RM back squat (p = 0.009, ES = 0.57), 1RM bench press (p = 0.005, ES = 0.61), repeated high-intensity exercise test (p < 0.001, ES = 0.88) and passing ability test (p < 0.001, ES = 0.99) discriminated elite from sub-elite counterparts. These findings highlight important attributes linked to elite U19 schoolboy rugby in Zimbabwe. However, no significant differences were observed for sum of seven skinfold (p = 0.28), tackling (p = 0.08) and catching ability (p = 0.05).

Selection and promotion processes are not associated by the relative age effect in an elite Spanish soccer academy.

The aim of this study was to analyze the influence of the relative age effect (RAE) on the selection and promotion processes in an elite soccer academy. One hundred and eleven elite youth players who belonged to an elite soccer club from the Spanish "La Liga" participated in this study. Players were classified into three age-categories: under 14 years (U14), under 16 years (U16) and under 18 years (U18); and they were also classified in quartiles based on their date of birth (i.e., January-March, Q1; April-June, Q2; July-September, Q3; October-December, Q4). In addition, two further classification criteria were established based on the selection (i.e., selected and non-selected players) and promotion (i.e., promoted and non-promoted players) processes. The main results showed that in U14 and U16 age-categories, players born early in the year were over-represented compared to players born late in the year, although birth-distribution was not associated with the likelihood of a player to be selected or promoted. In addition, less fat in sum skinfolds, less percentage of fat, higher percentage of muscle and lower endomorphy and mesomorphy components were showed in U14 selected players, in comparison with non-selected players. Likewise, better sprint performance was found in U16 selected players versus non-selected ones. However, no significant differences on anthropometry, body composition, somatotype and physical performance were found between promoted and non-promoted players. Therefore, our results suggest there is need for coaches to reorient their talent identification programs in order to make sure that players selected to continue playing in the club have the potential to promote to the excellence in soccer.

Validity and reliability of the TargetScan ISSF Pistol & Rifle application for measuring shooting performance.

Several technologies, with varying economic costs, are used to measure the performance of Olympic sport shooters, including electronic targets, laser systems, and mobile phone applications. Nevertheless, the International Shooting Sport Federation (ISSF) does not currently accept any mobile applications as valid measurement systems. The objective of the study was to check the validity and reliability of the TargetScan ISSF Pistol & Rifle application, an automatic mobile application for measuring the performance of shooters via image analysis. A total of 1440 shots were fired by 24 shooters (720 shots each for the air rifle and air pistol events), and the target sheets were analyzed with the application installed on an iPhone X. The official competition results and the measurements from the application were then compared. The results showed an almost perfect reliability for air pistol shots (ICC = .999) and no significant differences between the official average scores and those measured by the application. The reliability was also high for air rifle shots (ICC = .998), but the average scores registered by the application were statistically lower than the official results. We concluded that TargetScan ISSF Pistol & Rifle is a low-cost, valid, and reliable application for measuring amateur and semi-professional shooting performance which may be useful to shooters, coaches, clubs, and federations worldwide.

Quantification of aerobic determinants of performance in post-pubertal adolescent middle-distance runners.

PURPOSE: The use of oxygen cost ([Formula: see text]aero) parameters to predict endurance performance has recently been criticized. Instead, it is suggested that aerobic energy cost ([Formula: see text]) provides greater validity; however, a comparison of these quantification methods has not previously been made. METHODS: Fifty-six male (n = 34) and female (n = 22) competitive adolescent (17 ± 1 years) middle-distance runners participated in a sub-maximal and maximal incremental treadmill test. Running economy (RE) was measured at the speed corresponding to lactate turnpoint, and the three speeds prior. Maximal oxygen uptake ([Formula: see text]O2max), speed at [Formula: see text]O2max and fraction of [Formula: see text]O2max utilized across a range of intensities, and speeds from 0.8, 1.5 and 3 km races were also quantified. RE and fractional utilization were calculated in units of [Formula: see text]aero and [Formula: see text]aero. RESULTS: Multiple linear regression models demonstrated no discernible difference in the predictive capability of RE, fractional utilization and [Formula: see text]O2max when expressed as [Formula: see text]aero or [Formula: see text]aero in both sexes. When plotted as a function of running speed, [Formula: see text]aero displayed a stepwise decrease (F = 11.59, p < 0.001) whereas [Formula: see text]aero exhibited a curvilinear response (F = 4.74, p = 0.015). Differences were also evident in the slopes plotted for %[Formula: see text]O2max and %[Formula: see text]aeromax against running speed (F = 5.38, p = 0.021). CONCLUSIONS: Quantifying aerobic determinants of performance in units of [Formula: see text]aero provides no greater validity compared to [Formula: see text]aero-based measurement. Although both [Formula: see text]aero and [Formula: see text]aero are sensitive to changes in speed, [Formula: see text]aero provides the more valid reflection of the underlying metabolic cost of running. Physiologists should also be aware of the potential differences between expression of aerobic running intensity based upon %[Formula: see text]O2max compared to %[Formula: see text]aeromax.