Science & medicine in football最新文献

The purpose of this study was to compare the activity profile of elite Gaelic football referees (GFR) between the National Football League (NFL) and the All-Ireland Championship (AIC), and across the four divisions of the NFL and three phases of the AIC. Match activity data was collected during 125 NFL and 201 AIC games using 10-Hz global positioning system technology from 41 elite GFR. Game duration, total distance, very low-speed movement (<0.70 m·s^-1), walking (≥0.70-1.65 m·s^-1), low-speed running (≥1.66-3.27 m·s^-1), moderate-speed running (≥3.28-4.86 m·s^-1), high-speed running (≥4.87-6.48 m·s^-1), very high-speed running (≥6.49 m·s^-1) distance, and peak running speed were compared between competitions. Games in the AIC were longer than in the NFL (ES = 0.59) but the total distance was similar between the NFL (119.6 ± 9.5 m·min^-1) and AIC (122.6 ± 8.4 m·min^-1, ES = 0.11). No other differences were found between the NFL and AIC or across the four divisions of the NFL and three phases of the AIC, except for a higher peak running speed during the All-Ireland Series (6.93 ± 0.52 m·s^-1) than the All-Ireland Qualifiers (6.65 ± 0.46 m·s^-1, ES = 0.35). This information can be used to design specific conditioning programmes to ensure optimal physical development of GFR at all competitive levels.

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.

The aim of this study was to investigate the change of direction (COD) frequencies and intensities of high-performance soccer players of the German Bundesliga independent of tactical and match context. COD data were collected from 18 German Bundesliga soccer teams (season 2016-2017; 308 fixtures) by an optical tracking system (OTS) (TRACAB). CODs were tracked using a modified algorithm and were sub-categorized by entry velocity (<3.0 m⋅s^-1, 3.0-5.5 m⋅s^-1, 5.5-7.0 m⋅s^-1 and >7.0 m⋅s^-1) and COD angle (20-59°, 60-119° and 120-180°). COD metric frequencies were compared between playing positions (goalkeepers, centre backs, full-backs, central midfielders, wide midfielders, and strikers). In general, regardless of entry velocity or COD angle, central midfielders consistently executed the highest number of COD actions during matches compared to the other playing positions. About ≈ 55% and ≈ 38% of CODs were <3.0 m⋅s^-1 and <5.5 m⋅s^-1, whereas ≈ 7% were >5.5 m⋅s^-1. The distribution of COD angle types was ≈ 5% for 20-59°, ≈25% 60-119° and ≈ 70% for 120-180° COD angles. Our data provide insights into the COD demands of high-performance soccer in the German Bundesliga in terms of entry velocity and COD angles and their combination based on a large dataset of OTS data, which provides insights to facilitate the development of physical conditioning strategies, position-specific external load management, and multidirectional speed training with adequate test battery selection and return-to-play protocols for soccer players.

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.

The objective of this study was to investigate the barriers experienced by elite women football players due to their menstrual cycle, and coping strategies utilised against these barriers. Fifteen elite women footballers from two English Women's Super League clubs (age: 25.2 years [18-33]) were interviewed using semi-structured interviews, developed using piloting and peer review. Data was audio recorded, transcribed verbatim and analysed thematically using NVivo. Analysis of 27,438 words unveiled key themes: internal barriers, external barriers, coping strategies, and player needs. Fear of leakage, associated with kit colour (n = 15) and lack of effective sanitary products (n = 12), and injury anxiety (n = 7), associated with ACL injury (n = 5), were the most common barriers. To combat these issues, players use internal (feeling fortunate n = 9) and external (support from teammates n = 6; support from club staff n = 4) coping strategies. The findings indicated that menstruation presents significant barriers to players. Increased awareness of menstruation-related barriers to performance and targeted intervention are achievable through staff and player involvement and by minimising concerns of visible leakage by kit interventions.

We investigated the associations between Finnish top tier footballers' self-assessed leadership roles (task, motivational, social, external) and player-assessed head coach leadership behavior (supportiveness/emotional composure, negative activation) and leadership role in both practices and games. We also explored the player age- and gender-related differences. Online survey data were anonymously collected from 53 male and 91 female footballers. One player did not identify as male or female, and one chose not to answer the question. Spearman rank-order correlations revealed that players' self-assessed leadership roles correlated positively with their evaluation of their head coach's supportiveness/emotional composure and negatively with negative activation during practices and games. Independent samples T-tests showed that male footballers rated their head coaches lower on negative activation during games and practices and themselves higher on external leadership than female players. The youngest age group, aged 17-20, rated themselves also lower on external leadership than the three older groups.

The future of football demands more from players and referees due to heightened match intensity and frequency. To optimize performance and health, collaboration among sport scientists, coaches, and medical staff is crucial. However, match officials often lack the same support as elite players, hindering their development. Granting professional status to referees, implementing evidence-based training, and adopting gender-inclusive methods are vital. Coping with future challenges requires better career support and economic conditions for officials, along with research to enhance their performance and health.

This study investigates variations in skinfold thickness in a European professional football team within and across multiple seasons, including before and after COVID-19 restrictions. Skinfold thickness was measured in 49 male players on 32 occasions across three seasons (2018/19, 2019/20 and 2020/21). Intra- and inter-seasonal trends were examined by comparing values for the sum of eight skinfolds (sum8) at key time points using linear mixed models. In each season, the largest differences in sum8 occurred after the preseason period. These differences ranged from a mean difference (M_diff) of -11.0 mm (p < 0.001) in 2018/19 to -4.8 mm (p < 0.001) in 2020/21. Increases in sum8 occurred after each off-season; however, the increase after the off-season before the 2020/21 season (which included the COVID-19 lockdown period) was the lowest in magnitude and was not statistically significant (M_diff = 2.9 mm, p = 0.06). Changes occurring in sum8 between the start and end of the competitive season did not follow a consistent pattern and were generally smaller in magnitude than the changes between other seasonal time points. Despite the notable heterogeneity in sum8 between players, changes within players generally followed a similar pattern between the different seasonal timepoints. In summary, changes in skinfold thickness were predominantly related to off-season and 'preparation for competition' periods. Increases in skinfold thickness can be mitigated during extended remote training periods with appropriate training and nutritional strategies.

Introduction: Soccer coaches are critical to academies as they are central to identifying players with the potential to succeed (i.e., talent). Research suggests coaches perceive skill as determining players' potential. Regardless, researchers only broadly explored their views and quantified players' skill using objective measures, which is problematic as coaches still rely on their subjective intuition. A plausible reason is that skill assessments do not meet coaches' needs.

Objective: So,this study explored academy soccer coaches' perspectives on skilfulness.

Methods: Participants required a minimum B-level AFC/FA Pro Coaching Licence and five years' experience for inclusion. Australian soccer coaches (n = 4) and academy directors (n = 7) (M_age = 35.90 ± 8.36 years; M_experience = 14 ± 7.02 years) participated in semi-structured interviews (M_time = 50.73 ± 7.33).

Results: We analysed coaches' responses using reflexive thematic analysis, generating four themes describing skilful players as i) technically proficient, ii) adaptable, iii) effective decision-makers, and iv) influential to their team's success. We produced three themes on the situational and contextual nature of their views, perceiving skill through a v) developmental lens, relying on their vi) experiential knowledge, and their views were vii) context-specific.

Conclusion: Additional research is needed to create a refined conceptual model for assessing soccer skilfulness.