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.

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.

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.