Multidimensional and Longitudinal Approaches in Talent Identification and Development in Racket Sports: A Systematic Review.

BACKGROUND: Better methods to support talent identification and development processes may contribute to more effective and efficient athlete development programs in racket sports. Both researchers and practitioners recommend multidimensional and longitudinal approaches to better understand the nature of talent (development). However, the added value of these 'innovative' approaches has not yet been clarified for racket sports. This systematic review intends to gain further insight into the outcomes of multidimensional and longitudinal approaches for talent identification and development in racket sports and to provide directions for future talent research. METHODS: Electronic searches were conducted in PubMed, Scopus, SPORTDiscus, and Web of Science (January 2000-August 2022). Search terms covered the areas of racket sports and talent in sports. Studies using multidimensional and/or longitudinal talent approaches were included and analyzed regarding the methodology, included performance characteristics (i.e., anthropometrical, physiological, technical, tactical, psychological), and study findings. RESULTS: A total of thirty-two studies were included using multidimensional (n = 15), unidimensional longitudinal (n = 3) or multidimensional longitudinal designs (n = 14). Most research covered physiological characteristics (n = 28), while fewer articles investigated anthropometrics (n = 21) and technical characteristics (n = 16). Only limited research investigated psychological (n = 4) and tactical characteristics (n = 1). Almost all studies measured physiological characteristics in combination with other characteristics. There was moderate to strong evidence that physiological and technical characteristics have value for athlete development programs in racket sports. Positive but limited evidence was found for psychological and tactical characteristics. Anthropometrical assessments were generally used as controlling variables for maturation. Study designs varied, and many studies used unidimensional statistical models and analyses within multidimensional study designs and datasets. CONCLUSIONS: This review provides an overview of talent research using multidimensional and/or longitudinal approaches within racket sports and gives guidance on what characteristics to include in decision-making and monitoring processes. However, it remains difficult to draw conclusions about the added values of these approaches due to their variety in methodology. Future talent research should include more consistent study designs and conduct multidimensional and longitudinal studies using multivariate statistical approaches that benefit from the data's multidimensionality.

An unexpected shift in constant year effects in female elite handball.

One of the most convincing studies about the importance of the cutoff date in relative age effects was when Helsen et al. (2000) showed that a shift in the date directly resulted in a change of birth month distributions in soccer. Over the past four decades, the role of the birth year has also been associated with relative age effects (as reflected in constant year effects). In this investigation, two studies attempted to replicate the shift of birth year distributions caused by a change in birth years in international female handball. In Study 1, the results from the female handball world championship 2017 showed a significant within-year effect overall and a constant year effect for players born 1988 and after. A second study was conducted with female players from world championships in 2009, 2011, 2013, and 2015. Results demonstrated small effect sizes for most tests. However, there was an unexpected trend toward a constant year effect shift at the age of 28 years. Several hypotheses are presented as an explanation for this trend.

A machine learning approach for the classification of sports based on a coaches' perspective of environmental, individual and task requirements: A sports profile analysis.

Well-designed talent programmes in sports with a focus on talent identification, orientation, development, and transfer support the engagement of young individuals and the pursuit of elite performance. To facilitate these processes, an analysis of task, environmental and individual characteristics per sport is much needed. The aims of this study were to 1) analyse whether unique profiles per sport could be established by generic characteristics and 2) to discuss similarities and differences for the potential application in talent development and transfer. By means of a validated survey, 1247 coaches from 34 sports ranked 18 characteristics on importance to their sports (0 = not important - 10 = very important). To discriminate the responses per sport a Discriminant Analysis (DA) was carried out. To refine the DA-classification, Uniform Manifold Approximation and Projection (UMAP) with CatBoost classifier was performed. To test the performance of the CatBoost classifier-algorithm, a confusion-matrix was generated. The cross-validated DA showed that 70.2% of the coaches were correctly classified to their sport. The UMAP/CatBoost technique revealed 75.1% accuracy with correctly predicted responses per sport ranging from 18.2% (sailing) to 98.2% (soccer). With varying precision, the algorithm was able to differentiate sports by importance of its characteristics indicating similarities and differences per sport.

Can perceptuo-motor skills outcomes predict future competition participation/drop-out and competition performance in youth table tennis players? A 9-year follow-up study.

Tools that provide a fair estimate of young table tennis players' potential and their chances to succeed will support making decisions whether to commit to an extensive development program and the accompanying lifestyle. Consequently, this study included two research questions (RQ) to evaluate the capability of the Dutch perceptuo-motor skills assessment to predict competition participation/drop-out (RQ1) and competition performance (RQ2) in young table tennis players (n = 39; 7-11 years) using a tracking period of 9 years. The perceptuo-motor skills assessment consists of eight tests assessing gross motor function (i.e., sprint, agility, vertical jump) and ball control (i.e., speed while dribbling, aiming at target, ball skills, throwing a ball and eye-hand coordination). A Cox regression analysis demonstrated that a higher level of ball control was associated with a lower risk to drop-out from table tennis competition. The eye-hand coordination test appeared to be most suitable since it was the only test included in the multivariable Cox regression model (HR = .908; p = .001) (RQ1). Similarly, a multilevel regression analysis showed that a higher level of ball control was associated with a higher future competition performance. The eye-hand coordination and aiming at target tests were included in the multivariable multilevel model (p < 0.05; R2 = 36.4%) (RQ2). This evaluation demonstrates promising prospects for the perceptuo-motor skills assessment to be included in a talent development programme. Future studies are needed to obtain valid thresholds scores and clarify the predictive value in a larger sample of youth competition players.

How is the Topic of Intersex Athletes in Elite Sports Positioned in Academic Literature Between January 2000 and July 2022? A Systematic Review.

BACKGROUND: Within the topic of intersex athletes in elite sports, science has become a decisive factor in decision- and policy-making. However, in the academic literature approaches to this topic vary. An overview of these approaches is proposed to provide better insight into relevant aspects and underlying values and may serve as a starting point on the path toward a solid solution of the question of categorization of intersex athletes in elite sporting competition. OBJECTIVE: This systematic review aims to discover how the topic of intersex elite athletes is positioned in the academic literature from January 2000 to July 2022 from a neutral perspective. METHODS: A comprehensive search in eleven databases using the search terms [intersex* and sport*] yielded 87 articles. A qualitative content analysis was conducted to find all authors' statements including perspectives on intersex athletes and proposals for solutions. Underlying values were extracted and connected to each other during axial coding. RESULTS: The results provide an overview of the sometimes-contradictory perspectives toward intersex elite athletes and proposals for solutions. Three core values were distilled: social justice for intersex elite athletes, competition fairness, and evidence-based practice. The authors' statements disclose an interaction/conflict between social justice and competition fairness. CONCLUSIONS: The results raise an important discussion on the role of science within the topic of intersex elite athletes. A multidisciplinary approach including scientists and other experts is suggested to find an appropriate solution. Additionally, more awareness on intersex variations is needed for a better overall understanding and to ensure a respectful approach for everyone involved.

Low prevalence of relative age effects in Luxembourg's male and female youth football.

The relative age effect (RAE) is a well-established phenomenon in football. However, while the majority of previous studies focussed on established football nations, it remains unclear if the constraint of a limited population of soccer players in smaller countries associated with less strict selection procedures may reduce the risk of RAE. This study aims to investigate the RAE in Luxembourg that follows an 'open-door' selection policy in youth football due to the limited pool of players. Birthdates from all licensed and actively playing Luxembourgish youth footballers including all players of the youth national teams (396 girls and 10981 boys) competing in the season 2018/2019 were analysed and categorised into birth quarters and semesters. To further investigate a performance dependence of the RAE in amateur leagues, success was determined based on the teams' rankings at the end of the season. Differences between observed and expected birthdate distributions were calculated across all licensed players and age groups, within the national teams, and for the top- and bottom-tier football teams using chi-square statistics. While a RAE was absent across all age groups (except U7), significant RAEs with high effect sizes were observed in the top-level and national teams. These findings contrast the substantial RAE effects in large football nations and suggest that open selection systems might reflect an environmental constraint that limit the prevalence of RAE in football. Further, this study indicates that a performance dependence of the RAE is not limited to high level football but already occurs on an amateur level.

Primary School Pupils: Unequal GMC Developmental Pathways in a Single School Year.

Gross motor coordination (GMC) is essential for the development of specific motor skills and long-term participation in physical activities and sports. Group analysis reveals that, on average, children develop these skills gradually; however, how individuals develop GMC is less clear. The main aim of this study is to increase the understanding of developmental patterns within one school year, and whether children's grade, gender, or baseline GMC proficiency are associated with these developmental patterns. In total, 2594 Dutch children aged 6−12 years performed the modified Körper Koordinations Test für Kinder (KTK3+) twice in one school year (autumn and spring). The KTK3+ includes four subtests: walking backwards, moving sideways, jumping sideways, and eye-hand coordination (EHC) test. On average, children developed significantly on all subtests (p < 0.001). At baseline, children in higher grades scored significantly higher than children in lower grades, and children in grades 5 and 6 (age 9 and 10 years) showed most development (raw scores on average, p < 0.001). Boys outperformed girls on EHC across all grades, whereas girls outperformed boys on walking backwards. Nevertheless, both boys and girls developed similarly. Children with lower scores at baseline developed more quickly across all grades. Noteworthy is that 12.1−24% (depending on the test item) of the children scored lower in the spring than in the autumn tests. On average, children develop their GMC; however, we report large differences in their individual trajectories and note that a substantial number did not show a positive GMC development. Further research should examine GMC development with more possible influencing factors as well as over a longer time span to better understand differences in children's GMC development. This may result in more individualized programs in PE lessons, enabling children to optimally develop their GMC, and better use of GMC assessment tools to monitor children's development.

Design of a Tennis-Specific Agility Test (TAT) for Monitoring Tennis Players.

Agility is an important ability for tennis players. To be successful in the rallies, players must perform rapid, multidirectional movements in response to the ball and/or the position of the opponent. For a test to be representative in monitoring agility performance, it should capture a combination of the physical and cognitive agility performance. Considering that literature reports no reliable and valid sport-specific agility test for tennis, the aim of this article was to design and evaluate the measurement properties of a Tennis-specific Agility Test (TAT). To evaluate the TAT, test-retest reliability, concurrent validity, and feasibility were assessed. For reproducibility, a two-way mixed ANOVA was performed. Concurrent validity was assessed using Pearson correlations. A total of 69 tennis players participated in this study of whom 16 competed at the international (22 ± 3.7 years, playing level (Dynamic Rating System): .8 ± .3), 43 at the national (14 ± 1.4 years, playing level: 4.6 ± 1.4), and 10 at the regional level (15 ± 0.8 years, playing level: 4.9 ± 1.1). Test-retest reliability was found to be moderate with an Intra-Class Correlation coefficient (ICC) of .74 (p < .01) and a percentual minimal detectable change (%MDC) of 6.2%. Concurrent validity was found to be moderate by comparison with a recognised agility test, the Spider Drill, which measures only the physical component (.70; p < .01), and by comparison with tennis performance for both boys (r = .67; p < .01) and girls (r = .72; p < .01). The feasibility was high with short time for preparation (five to ten minutes) and time per participant (<5 minutes). In conclusion, the TAT shows promising results for assessing sport-specific agility performance in tennis making it likely to be used in the practical setting.

Developing a tool to assess technical skills in talented youth table tennis players-a multi-method approach combining professional and scientific literature and coaches' perspectives.

BACKGROUND: The assessment of technical skills as part of a multidimensional approach for talent identification and development in sports seems promising, especially in a technique-based sport like table tennis. However, current instruments mostly focus on a single element of technical skills, mainly use quantitative outcomes, and/or are not developed for talent purposes. Practice would benefit from a new instrument using a more ecologically valid approach. Thus, the purpose of this study was to identify the essential elements of technical skills in young table tennis players and to establish a first tool while using a multi-methods study design including an archive search for professional literature, a systematic search for scientific literature, as well as ten in-depth interviews with expert coaches. RESULTS: This approach taken ensured empirical findings to be combined with knowledge and experiences from the practical field and detailed explications by high-level expert coaches. Results for the literature searches yielded 23 professional and 21 scientific articles while data saturation was reached through all ten interviews. The triangulation process resulted in two general (i.e., individuality, interconnection between elements) and five specific (i.e., bat grip, ready position, footwork/body positioning, service, stroke) elements of technical skills in young table tennis players. In addition, criteria for both flawed and excellent executions were identified for each of the five specific elements. Finally, these results were used to create an observation sheet usable for an assessment during competition. CONCLUSIONS: This study revealed the crucial elements of technical skills that should be taken into account when assessing sport-specific technical skills of youth table tennis players (8-12 years). Moreover, it provided concise descriptions of what is considered to be flawed or excellent executions of technical skills. Based on these findings, a first observation sheet, the Oldenburg observation sheet for Table Tennis Technique (O3T), was created to be used for the assessment of the current technical skill level within a competitive context at the early stage of a table tennis player's career. Future research should focus on its measurement properties and its value within a multidimensional assessment for talent purposes.

Similarities and differences between sports subserving systematic talent transfer and development: The case of paddle sports.

OBJECTIVES: The aim of this study was to investigate similarities and differences for 18 sports toward canoe/kayak in order to identify donorsport and/or multisports, based upon a systematic analysis of the task constraints per sport that are assumed to be either crucial or less important from the coaches' viewpoint. DESIGN: Descriptive survey analysis. METHODS: 891 certified coaches from 19 sports valued (0-10; not important at all-very important) 15 characteristics by a questionnaire (Flemish Sports Compass) within their sport. Unique sport-profiles (discriminant analysis - DA) were constructed for 19 sports based on these characteristics. Similarities and differences between canoe/kayak and the other 18 sports were analyzed by means of MANOVAs on anthropometric, physical and motor coordination characteristics. RESULTS: Cross validated DA (rcan=0.660, Wilks' Lambda=0.564, p<0.001) showed that 72.1% of the canoe/kayak coaches were correctly assigned to their sport. For canoe/kayak seven characteristics were valued crucial; dynamic balance (8.51±1.69), core stability (8.45±2.27), pulling power (8.12±1.68), speed (7.54±2.07), endurance (7.27±2.03), stature (6.43±1.41) and rhythm (6.01±3.01). Least important characteristics were: flexibility (6.16±1.75), agility (4.27±3.10), catching (3.90±3.22), climbing (2.45±3.05), jumping (1.81±2.11), throwing (1.60±2.24), hitting (.94±1.77) and kicking (.61±1.04). CONCLUSIONS: This novel approach to determine important characteristics per sport makes identifying similarities and differences between sports possible. Similarities might enlarge talent-pools for possible talent transfers. Differences can help identify sports based on complementary characteristics for the construction of broad motor development programs. From this viewpoint gymnastics can serve as potential donorsport (similarities) for canoe/kayak, while handball and tennis can subserve broad development for young canoe/kayak athletes.

A 2-year longitudinal follow-up of performance characteristics in Chinese male elite youth athletes from swimming and racket sports.

Training in elite sport aims at the optimization of the athletic performance, and to control the athletes`progress in physiological, anthropometrical and motor performance prerequisites. However, in most sports, the value of longitudinal testing is unclear. This study evaluates the longitudinal development and the influence of intense training over 2-years on specific physiological performance prerequisites, as well as certain body dimensions and motor abilities in elite youth athletes. Recruited between 11-13 years of age at Shanghai Elite Sport school, the sample of student-athletes (N = 21) was categorized as the swimming group (10 athletes), and the racket sports group (11 players: 7 table tennis and 4 badminton players). The performance monitoring took place over two years between September 2016 and September 2018 and included 5 test waves. In all the test waves, the athletes were assessed by means of three physiological measurements (vital capacity, hemoglobin concentration, heart rate at rest), three anthropometric parameters (body height, body weight, chest girth), and two motor tests (back strength, complex reaction speed). Seven out of eight diagnostic methods exhibit medium to high validity to discriminate between the different levels of performance development in the two sports groups. The investigated development of the performance characteristics is attributed partly to the inherited athletic disposition as well as to the different sport-specific training regimens of the two sports groups.

Predictive value of coaches' early technical and tactical notational analyses on long-term success of female handball players.

Despite the importance of technique and tactics for athlete performance, there has been surprisingly little research on the value of these skills in talent identification and development. This study investigated the relationship between coaches' early notational analyses of female youth handball players and the long-term success of these athletes. Participants included sixty-eight female handball players involved in a talent selection camp in Germany when they were between 12 and 14 years of age (mean = 14.42, SD = 0.42). All subsequently ended up as non-, semi- or professional adult players. During the initial selection camp, participants were evaluated on a range of quantitative and qualitative measures of technical and tactical skill. Results indicated significant differences between the groups, but only for the number of actions taken, not for the quality of those actions. While this seems counterintuitive, it may reflect the likelihood that more skilled and/or talented players take more actions. Further work is necessary to explore the validity and implications of these findings.

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.

Are performance trajectories associated with relative age in French top 100 youth table tennis players? - A longitudinal approach.

Although relative age effects in sports have been studied worldwide, the underlying mechanisms are still under debate. This study adds to the existing knowledge by providing a further exploration of the association between relative age and the performance trajectories over four years in youth players of an individual skill/technique based sport: table tennis. Data of 1000 French male and female youth top 100 players across five ages (U14, U15, U16, U17 and U18) were collected from the ranking lists over a four-year period. A series of latent growth analysis was conducted per subsample and revealed three performance trajectories for male U14, U16 and U17 as well as for female U17 and U18 and four performance trajectories for male U15 and U18 and female U14, U15 and U16. Results of chi-square tests revealed that the players' birth quartiles were significantly associated with the performance trajectories only for male players U18 with a large effect size (p = 0.01; W = .48). All other male subsample only showed a trend for the male subsamples for those born in the fourth quartile. No relations or trends were found in the female subsamples. Future research in relative age effects should further explore individual characteristics and pathways while using a longitudinal approach in a prospective design and evaluate influencing constraints (and solutions) in a more comprehensive way.

Do Older Adults With Reduced Bone Mineral Density Benefit From Strength Training? A Critically Appraised Topic.

Clinical Scenario: Reduced bone mineral density (BMD) is a serious condition in older adults. The mild form, osteopenia, is often a precursor of osteoporosis. Osteoporosis is a pathological condition and a global health problem as it is one of the most common diseases in developed countries. Finding solutions for prevention and therapy should be prioritized. Therefore, the critically appraised topic focuses on strength training as a treatment to counteract a further decline in BMD in older adults. Clinical Question: Is strength training beneficial in increasing BMD in older people with osteopenia or osteoporosis? Summary of Key Findings: Four of the 5 reviewed studies with the highest evidence showed a significant increase in lumbar spine BMD after strength training interventions in comparison with control groups. The fifth study confirmed the maintenance of lumbar spine density due to conducted exercises. Moreover, 3 reviewed studies revealed increasing BMD at the femoral neck after strength training when compared with controls, which appeared significant in 2 of them. Clinical Bottom Line: The findings indicate that strength training has a significant positive influence on BMD in older women (ie, postmenopausal) with osteoporosis or osteopenia. However, it is not recommended to only rely on strength training as the increase of BMD may not appear fast enough to reach the minimal desired values. A combination of strength training and supplements/medication seems most adequate. Generalization of the findings to older men with reduced BMD should be done with caution due to the lack of studies. Strength of Recommendation: There is grade B of recommendation to support the validity of strength training for older women in postmenopausal phase with reduced BMD.

Higher-level cognitive functions in Dutch elite and sub-elite table tennis players.

This study aimed to investigate the higher-level cognitive functions (i.e. metacognition and executive functions) of Dutch competitive table tennis players to better understand its relevance for performance in this fast and complex sport. Thirty elite (age 16 ± 4) and thirty age and sex-matched sub-elite peers (age 16 ± 5) were assessed on metacognition and executive functions (working memory, inhibitory control, cognitive flexibility) using D-KEFS tests. Compared to norm scores, both the Dutch competitive elite and sub-elite table tennis players scored above average on all tests (p < 0.05). MANOVA showed a main effect for performance level (elites outscored sub-elites; p < 0.05). T-tests revealed that elite players make less mistakes on tests for inhibitory control (CWI-3: 0.9 ± 0.9; CWI-4: 1.1 ± 1.2) than sub-elite players (CWI-3: 1.8 ± 1.1; CWI-4: 2.6 ± 1.5) (p < 0.05). When controlling for training hours in a MANCOVA, no significant main effect of performance level remained (p > 0.05). In conclusion, Dutch elite and sub-elite table tennis players are characterized by above-average scores on higher-level cognitive functions compared to norm scores. A relation with performance level has been shown, which may be explained by the greater exposure to table tennis for elite compared to sub-elite players. However, longitudinal research is needed to indicate the direction of this association.

The prognostic relevance of psychological factors with regard to participation and success in table-tennis.

This study examined the prognostic relevance of self-determined motivation, coping, burnout, perceived stress and recovery experienced by 159 youth table-tennis players involved in intensive training centers with regard to their participation and success six years later. Results of ANCOVAs showed that players who still practiced at time 2 (T2; six years later; n = 130) reported lower time 1 (T1; while they were involved in intensive training centers) amotivation (large effect), disengagement-oriented coping, sport devaluation and reduced accomplishment (moderate effects) than their counterparts who dropped out at T2 (n = 29). Results of ANCOVAs also showed that international (n = 18) and/or national players (n = 86) at T2 reported significantly lower T1 amotivation (large effect), disengagement-oriented coping and sport devaluation (moderate effects) in comparison to regional (n = 26) players at T2. Finally results of correlational analyses showed that T2 performance and/or six-year performance progress were significantly and weakly correlated with introjected and external regulations, perceived stress and perceived recovery, and significantly and moderately correlated with amotivation, disengagement-oriented coping, sport devaluation, and reduced accomplishment. Overall, this study provided insights into the role played by self-determined motivation, coping, burnout, perceived stress and recovery in the table-tennis players' dropout and performance level six years later.

Does the Lever Sign Test Have Added Value for Diagnosing Anterior Cruciate Ligament Ruptures?

BACKGROUND: Diagnosing an anterior cruciate ligament (ACL) rupture based on a physical examination remains a challenge for both surgeons and physical therapists. The lever sign test was developed to overcome the practical limitations of other tests and to optimize diagnosis. An evaluation of the measurement properties of the lever sign test is needed to make adequate interpretations in practice. PURPOSE: To evaluate the reliability and diagnostic value of the lever sign test. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: A total of 94 patients were recruited between November 2014 and July 2016. Patients were included if they were at least 16 years old, suffered from knee trauma, and had indications for knee arthroscopic surgery. Lever sign, anterior drawer, Lachman, and pivot-shift test outcomes were examined by an orthopaedic/trauma surgeon and a physical therapist. A test-retest design was used to investigate interrater reliability. Moreover, the lever sign test outcomes, alone and in combination with the other diagnostic tests, were compared with arthroscopic results, which served as the gold standard for the test's diagnostic value. RESULTS: The lever sign test and pivot-shift test had kappa values exceeding 0.80 for interrater reliability. The kappa values for the anterior drawer test and Lachman test were 0.80 and 0.77, respectively. The lever sign test showed the highest specificity (100%) and the lowest sensitivity (39%) when compared with the other 3 tests. Moreover, its positive and negative predictive values were 100% and 65%, respectively, while an accuracy of 71% was calculated. Clustering the lever sign test parallel with the other 3 tests resulted in the highest accuracy of 91%. CONCLUSION: The lever sign test appears to have high interrater reliability and is the most specific test, showing a maximal positive predictive value. A positive lever sign test result indicates an ACL rupture. These results support the added value of the lever sign test for diagnosing ACL ruptures.

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

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.