Science & medicine in football最新文献

The balance of primary sport practice and multisport participation during childhood for later success in sport has been debated in models of athlete development. Various mechanisms have been proposed regarding why activity diversity would aid development, including motivation. Here we test this mechanism by assessing childhood sport and other types of activity diversity (within-sport and non-sport activity) among female competitive adolescent athletes in soccer (N = 211; 12-19 yr) and measures of motivation. Athletes in four skill groups (grassroots/Div. 2 to Nationally competitive) completed an online survey about their practice history in soccer (number of teams, positions and play hours), other sports and non-sport activities, and motivation and commitment. Not surprisingly, higher skill groups participated in more childhood soccer practice than lower skill groups, but they showed less sport diversity and there were no differences in non-sport activity participation. The higher skill groups reported more soccer play and more team diversity than lower groups, but showed greater position specialization in childhood. Total (and relative) hours in soccer practice and play (compared to non-soccer) were positively correlated with soccer motivation. These data are consistent with pathways of skill development in soccer based on early majority engagement in the primary sport; without exclusive engagement and high amounts of play. Sampling between sport or other activities was not related to skill or motivation, so there was no evidence of between-activity transfer related to enhanced motivation for soccer.

The purpose of this study was to investigate players' experiences and perceptions of the menstrual cycle (MC) and the perceived impact on performance. Female elite adult (n = 31, age 24.6 ± 5.1 years) and adolescent (n = 65, age 15.0 ± 1.1 years) players completed an online questionnaire consisting of quantitative and qualitative questions. MC symptoms were experienced by 90.1% naturally menstruating participants (86.9% adolescents and 93.6% adults (x² = 1.53, df = 2, p = 0.47, n = 92)), and 78.3% adolescents perceived their MC impacts performance, compared to 96.4% adults (x² = 4.54, df = 1, p = 0.033, n = 74). Physical symptoms, psychological symptoms and energy levels were cited as key reasons for the MC negatively impacting performance. Challenges in communicating MC experiences were reported by 44.92% (n = 23) adolescents compared to 20.0% (n = 6) adults (x² = 7.29, df = 2, p = 0.026, n = 82), with a perceived lack of knowledge, ability to relate and awkwardness cited as key reasons. Football players report wellbeing and performance impacts due to their MC, highlighting the need for individual understanding and support. Furthermore, understanding the experiences of adolescents enables the development of targeted support structures that equip them with tools to manage and communicate about their MC, and hopefully preventing issues as they become senior players.

The question of how best to identify and develop youth soccer players has received considerable attention from the scientific community. Existing literature has, however, largely focused on male players, with comparatively little exploration of the specific approaches employed within women's soccer. Accordingly, we sought to investigate the key factors deemed important by elite women's soccer clubs concerning the: 1) identification of potential talent; 2) development of players within the player pathway; and 3) selection of players for the next age group or senior team. Data were generated through semi-structured interviews with 11 key representatives from seven elite women's soccer clubs. Clubs were purposefully sampled to include the highest performing teams (38 domestic titles and 10 UEFA Women's Champions League titles) from five European nations (Spain, France, Sweden, Germany, and Italy). Data were analysed using thematic content analysis, resulting in six higher-order themes: 1) prioritising local talent; 2) recruitment from mixed grassroots leagues; 3) creating challenging developmental environments; 4) ensuring player wellbeing; 5) patience in decision-making; and 6) facilitating the youth-to-senior transition through a top-down approach. A total of 17 lower-order themes were subsequently identified. The present study offers novel insights of key strategies deemed important by some of the most successful women's clubs in top-performing European nations. Future research examining the efficacy of such approaches could help inform the development of evidence-based practices for nurturing the next generation of elite female players.

In this study, we examined whether the 0-10 rating of perceived effort (RPE) scale can serve as a method for prescribing playing intensity in small-sided games (SSGs). We conducted a randomized crossover trial involving 25 young male football players (age range 16-18 years). Participants completed a familiarization and three experimental sessions where game intensity was regulated using prescribed intensities equal to RPE of 6, 8, or 10. Each session involved six teams of three players playing in three SSGs, with 4 min of rest, in a playing area of 133 square meters per player. Outcomes included total distance, high-speed running distance (HSRD), intense acceleration and deceleration (IAD) counts, and average heart rate (HR). We fitted mixed models and estimated 95% confidence intervals (CIs) to analyze the results. The CIs for all locomotive outcomes indicated an increase at RPE-8 and RPE-10 compared to RPE-6. Notably, the effects on HSRD and IAD were substantial, with differences between RPE-10 and 8 to RPE-6 ranging from 28% to 97%. Conversely, differences in the total distance the players covered per game between RPE-10 and 8 to 6 were minor (~5%). We could not identify clear differences between RPE-10 and 8 in the locomotive outcomes (differences range 0%-9.6%, CIs containing zero) nor in HR across all RPE conditions (differences range 1-3.5 bpm, CIs containing zero). We conclude that RPE can serve as a practical tool to prescribe medium or high intensity during SSGs, although its ability to differentiate between higher intensity levels or influence heart rate is limited.

Relations between load and acute psychophysiological responses have been widely studied in football. However, due to the large heterogeneity in contexts, operationalization, and results, the direction and strength of these relations remain unclear. In this meta-analysis, we examine the relation between load and typical acute (i.e. within one week) responses - wellbeing, recovery, and heart rate measures - in football players from all football codes (soccer, rugby, futsal, American football, and Australian rules football). We consulted PubMed, Web of Science, and CINAHL up to the 19^th of June 2024, and included 62 articles and 1,474 participants in the meta-analysis. Subsequently, we estimated 12 meta-analysis models and applied meta-regression models to explore the influence of several moderators. Significant relations were found between load and overall wellbeing (r = -0.33 [95%CI: -0.48; -0.19]), muscle soreness (r = -0.36 [95%CI: -0.49; -0.24]), fatigue (r = -0.41 [95%CI: -0.56; -0.26]), sleep quality (r = -0.21 [95%CI: -0.31; -0.10]), and stress (r = -0.16 [95%CI: -0.26; -0.06]). Given the high risk of bias, inconsistency (wide prediction intervals), and imprecision, the certainty in these findings based on the GRADE assessment is very low. Additionally, the high risk of bias scores indicates that the overall quality of the included studies is low. In conclusion, this meta-analysis provides comprehensive information on the acute responses of the athlete to load, and directions for improvement of the quality of future studies.

This study explores whether referees are biased when awarding additional time in Association Football. We collected data on Awarded Additional Time (AAT) granted by the referees and Calculated Additional Time (CAT), representing the interruption time meant to be considered for additional time according to the rulebook. Analysis of Additional Time Error (ATE), given as the difference between CAT and AAT, in the second half of German football Bundesliga season 2022/2023, revealed that referees award less AAT than warranted by interruptions (ATE = 2:10 ± 2:24 min). Multiple Linear Regression between either AAT or ATE and the duration of interruption types suggests that referees do not consider Goal Celebrations (for AAT: β = 0.09, p = 0.09, for ATE: β = 0.52, p < 0.01) as important as Substitutions (for AAT: β = 0.25, p < 0.01, for ATE: β = 0.03, p = 0.68), Injuries (for AAT: β = 0.35, p < 0.01, for ATE: β = 0.28, p < 0.01) and VAR (for AAT: β = 0.38, p < 0.01, for ATE: β = 0.10, p = 0.10). Mann-Whitney U-tests indicate a referee's bias towards allocating insufficient AAT in matches with a goal difference greater than one compared (ATE = 3:16 ± 2:26 min) to the other matches (ATE = 1:18 ± 2:00 min) (p < 0.01, ES = 0.17). The Kruskal-Wallis H tests also show slight home bias from the referees, indicating that ATE is higher when the home team is leading more than one goal (ATE = 3:36 ± 2:36 min) (p < 0.01, ES = 0.15). In conclusion, although German Bundesliga referees adhere to the Laws of the Game, they show inconsistencies in handling different interruption types and matches with decisive outcomes. The findings suggest potential enhancement in referee training and decision-making processes and should be considered when advancing the game.

Talent identification and development (TID) in football can be enhanced through objective assessments of talent predictors. Yet, available instruments rarely consider the unique demands of goalkeepers (GKs). During early phases of talent development, considering a GK's giftedness relating to, for example, different abilities (e.g. motor coordination), can complement views on highly specialized GK-specific attributes (e.g. technical skills). Therefore, this study aimed to evaluate a GK-specific motor coordination assessment to support TID in football at early developmental phases. Six tests were designed to assess ball control relevant to GKs. Their content and face validity were confirmed by independent experts (N = 8). The assessment was evaluated with GKs selected for the German Football Association's TID program (U12-U15; N = 120). This study examined the assessment's test-retest reliability and agreement, the structural validity, and the concurrent validity. The overall test score demonstrated good test-retest reliability, although some individual tests showed lower coefficients. Additionally, limited agreement between repeated measurements due to considerable measurement error as well as issues with the structural validity of the test battery were identified. Nevertheless, the findings support the assessment's concurrent validity as higher-rated (i.e. more talented) GKs outperformed lower-rated individuals. Yet, the test battery's diagnostic accuracy is not high enough to justify individual decisions for talent selection. Overall, these findings support the consideration of motor coordination as a talent predictor in youth GKs and emphasize the assessment's potential to enhance coaches' evaluations. The identified psychometric weaknesses in some individual tests provide impetus to further optimize the test battery.

This study aimed to investigate the criterion validity of commonly used devices to assess maximal sprinting speed (MSS) in soccer. Thirty elite youth soccer players completed three trials of a 30-m sprint test to assess MSS. All sprints were simultaneously captured via a radar gun (Stalker ATS II), timing gates (Smartspeed Pro, Fusion Sport), a magnetic timing system (Humotion SmarTracks) and a global navigation satellite system (GNSS) (Kinexon Perform GPS Pro). The radar gun and the GNSS recorded sprinting speed continuously, while the fastest 5-m split during the 30-m sprint was used for the timing gates and the magnetic system. The best trial of the radar gun (i.e. criterion measure) and corresponding values of the other devices were analyzed. Equivalence testing was performed to assess the statistical equivalence of MSS between the radar gun and the three other devices against a difference value of ± 0.36 km/h and Bland & Altman's 95% limits of agreement (LoA) were computed to investigate the agreement between MSS results. Differences between GNSS versus radar gun suggested a lack of systematic bias (-0.01 km/h, 95% confidence interval [CI] -0.15 to 0.15 km/h), whereas timing gates-based MSS assessments were prone to larger uncertainty compared to the criterion method (-0.19 km/h, 95% CI: -0.37 to 0.00 km/h) given the pre-defined region of equivalence. The magnetic system (-0.54 km/h; -0.71 to -0.37 km/h) overestimated MSS compared to the radar gun with mean differences being non-equivalent. Based on the practically important difference bounds of ± 0.36 km/h, the width of the 95% LoA was broad enough to suggest a lack of reasonable agreement for MSS assessment regardless of device of interest (GNSS: -0.79 to 0.78 km/h, timing gates: -0.79 to 1.16 km/h, magnetic system: -0.24 to 1.32 km/h). While our results suggested a lack of systematic bias for the investigated GNSS and the timing gates when compared against the radar gun for MSS assessment over 30 m in elite youth soccer players on a team level, the width of the 95% LoAs did not indicate reasonable measurement interchangeability on an individual level. Based on the present results, we do not recommend using the magnetic system for both group and individual analyses in this population.