Relative age effects in soccer are typified by an overrepresentation of players born earlier in the selection year. Examinations of relative age effects remain limited in female players and developing soccer nations. The aim of the present study was to examine the influence of sex, age, nation, playing position, and playing status in international level soccer players under Confederation of North, Central American and Caribbean Association Football (Concacaf). The sample consisted of a total of 1,959 active soccer players from 24 soccer nations that competed in recent Concacaf Championships. Results indicated an evident relative age effect in male [p < 0.05] but not female [p = 0.81] players. Male players were over-represented by players born in the first quartile for the U17 [p < 0.01] level, however, this over-representation did not transfer to the U20 or senior levels. No relative age effects were observed at any level for female players. A large proportion of nations demonstrated relative age effects in male, but not female samples. Relative age effects were shown for players participating at age group level, but not those 'playing-up'. Results from this study highlight the continued disparity in relative age effects prevalence between male and female players raises further questions regarding the value of selecting relatively older players to metrics of success, transition, and selection for senior international soccer. This information can be used to advance talent identification and development in Concacaf nations.
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The present study aimed to construct a multidimensional performance profile of men's elite youth national teams from the 6 continental confederations (AFC, CAF, CONCACAF, CONMEBOL, OFC, and UEFA) by examining physical, technical-tactical, spatial, and passing network characteristics at the 2023 FIFA U-17 and U-20 World Cups. Data from 174 match observations and 943 player observations were analyzed using mixed-effects models. At U-17, confederation-related differences were observed across physical, spatial, and passing-related domains. AFC players covered more total distance than CONMEBOL (P = .006, effect size [ES] = 1.55), while CAF players reached higher top speeds than OFC (P = .030, ES = 0.87) and showed greater team length in the middle and defensive thirds (mean difference [MD] = 3.55 to 10.19 m, P = .004-.040). UEFA showed stronger passing-related profiles than OFC, including higher pass and line-break completion (MD = 0.17 to 0.28, P ≤.005) and higher passing network density, global efficiency, and average clustering coefficient (MD = 0.08 to 0.16, P = .004-.036). At U-20, physical and most spatial differences were limited, whereas passing network differences persisted, with OFC teams showing lower density than all other confederations (MD = -0.17 to -0.11, P < .001-.018) and lower global efficiency than CONCACAF, UEFA, and CAF teams (MD = -0.09 to -0.08, P = .005-.012). Confederation-related profiles were more prominent at U-17 but became less evident in physical and spatial domains by U-20, whereas passing-related differences persisted and highlighted collective passing organization as an important feature of elite youth football development.
Physical performance demands in elite international football have evolved substantially in recent decades, yet longitudinal comparisons across FIFA confederations remain limited. This study examined long-term changes in physical performance demands among outfield players from five confederations (UEFA, CONMEBOL, CONCACAF, CAF, and AFC) using tracking data from 225 matches at the 2010-2022 FIFA World Cups. Generalised mixed linear models were used to estimate changes in total distance, top speed, sprint (>25 km·h ⁻ ¹), low-intensity running distance (<15 km·h ⁻ ¹), and high-intensity running distance (≥15 km·h ⁻ ¹), with confederation as the main factor and match status, location, and team and opponent strength controlled. Across confederations, substantial increases were observed in top speed, sprint, and low-intensity running distance from 2010 to 2022, indicating a uniform rise in speed-related demands. In contrast, changes in total distance and high-intensity running distance were confederation-specific. Total distance increased between 2018 and 2022 in AFC, CONCACAF, and UEFA, but showed no substantial change in CONMEBOL. High-intensity running distance declined in AFC, CONMEBOL, and UEFA, while changes in CAF were trivial. These findings indicate that speed-related demands have increased globally, whereas total and high-intensity running demands remain region-specific across FIFA World Cup editions.
To describe and characterize injuries reported in professional soccer athletes participating in the 2019 Confederation of North, Central America and Caribbean Association Football (CONCACAF) Gold Cup tournament. Data were collected from electronic medical reports submitted after each match of the 2019 CONCACAF Gold Cup tournament. Reports were generated from a 20-question online survey completed by team physicians from all 16 participating teams. For every recorded injury, a separate survey was completed by team physicians documenting athlete demographic characteristics, context of injury, injury characteristics, and expected time lost from injury. A total of 62 surveys were distributed, of which 80% (50 of 62) were collected for analysis. A total of 27 injuries (7%) were recorded among the 368 participating athletes. Injuries most frequently occurred during matches (92%, 24 of 27), with a significantly higher number of injuries recorded between the 61st and 75th minutes of play (P < .05). New injuries constituted 85% of all injuries (23 of 27), whereas 15% of injuries (4 of 27) were recorded as recurrences of prior injuries. Defenders had the highest number of injuries (41%, 11 of 27). Injuries to the lower extremities comprised 52% of all injuries (14 of 27), with thigh strains being the most common. During the 2019 CONCACAF Gold Cup, injuries were recorded in 7% of athletes (27 of 368), with 89% of injuries recorded as occurring during match play, primarily consisting of injuries involving strains to the thigh. Understanding the epidemiology of soccer (football) injuries can help physicians better educate athletes including their patients.
This study aimed to benchmark and analyze match performance of elite soccer players from various confederations during the FIFA World Cup Qatar 2022 (Men's WC) and FIFA Women's World Cup Australia and New Zealand 2023 (Women's WC). A total of 128 matches were analyzed using an optical tracking system (n = 1,351 player observations). Players from various national teams were categorized into their respective confederations: Europe (UEFA), South America (CONMEBOL), North/Central America and Caribbean (CONCACAF), Africa (CAF) and Asia and Oceania (AFC/OFC). Generalized Linear Mixed Models and Linear Mixed Models were employed to assess performance differences between confederations. Data revealed that CONMEBOL players in the Men's WC covered less total distance than UEFA players (p = 0.0396; ES = 0.6). However, no differences were found in high-intensity running and sprinting distances across confederations in both tournaments. UEFA players in both competitions typically demonstrated superior technical/tactical performances. In particular, UEFA players in the Women's World Cup made more passes, had 7-16% higher pass completion rates and achieved 10-15% greater line break completion rates compared to those from CAF, CONCACAF and AFC/OFC (p < 0.0001 to p = 0.0199, ES = 0.5-1.3). These findings suggest that UEFA players may possess a tactical/technical edge in international competitions. However, caution should be exercised when interpreting data due to high variations within confederations. This is the first comprehensive study describing match performance between confederations during the Men's and Women's WC, providing valuable insights into the physical and technical/tactical aspects of elite soccer.
Background/Objectives: The role of body composition in sports performance has been widely studied, particularly in soccer. Understanding how anthropometric characteristics impact movement efficiency and neuromuscular performance is crucial for optimizing player performance. This study examined the relationship between body composition and locomotor performance in elite soccer players. Methods: Thirty-six male soccer players from the Mexican National Team participated in the study, where body composition was assessed using surface anthropometry. Players underwent tests to measure countermovement jump (CMJ) performance, sprinting speed, maximum acceleration, and distance covered during two games of the CONCACAF Nations League quarterfinals. Correlation matrices were created to identify the most significant associations, followed by generalized linear models (GLMs) to associate body composition variables with performance metrics. Results: Anthropometric profile tables were created by playing position. Higher body fat percentage (%BF) was associated with lower performance. Specifically, higher %BF was associated with slower sprint speed (B = -0.74 m/s, p < 0.001) and shorter distance covered (B = -4.86 m/min, p < 0.001). Conversely, greater muscularity, reflected by corrected girth values for the thigh and calf, was associated with improved CMJ performance. Thigh corrected girth was positively associated with concentric mean force (B = 48.85 N, p < 0.001), and calf corrected girth was positively associated with peak power (B = 240.50 W, p < 0.001). These findings underscore the importance of low body fat and high lean mass for efficient movement. Conclusions: The results highlight the critical role of body composition in enhancing soccer performance, particularly for explosive movements like jumps, sprints, and accelerations. This study suggests that monitoring and optimizing body composition should be a central focus of nutrition, training, and conditioning strategies, adapted to the specific positional demands of professional soccer.
With the purpose of quantifying the differences in the running performance of soccer players during matches from different continental confederations, data of 1508 match observations generated from 559 players in 59 matches at the 2018 FIFA World Cup held in Russia were analyzed. Generalized mixed linear modeling was carried out to estimate the effect of confederations on each of the selected thirteen match running performance related variables (total distance covered, top speed achieved, number of sprints, distance covered and time spent in walking, jogging, low-speed running, moderate-speed running, and high-speed running), controlling the effects of match result, competition phase, and team and opponent strength. Results showed that the differences in the match running performance of UEFA and CONMEBOL players were trivial (ES between 0.04 and 0.14); players from AFC, CAF, and CONCACAF covered less total distance (ES between 0.26 and 0.54), spent less playing time, and covered less distance in jogging and low-speed running (ES between 0.20 and 0.53), whereas they spent more time walking (ES between 0.27 and 0.41) as compared with players from UEFA and CONMEBOL; top speed achieved, number of sprints made, and time spent and distance covered in the moderate- and high-speed running intensity zones by players from all confederations were similar (ES between 0.01 and 0.15), with an exception that high-speed-running distance covered by CONCACAF players was less than that by CAF players (2.0 ± 1.5 m/min vs. 2.3 ± 1.7 m/min, ES = 0.23, ±90% CL: ±0.21).
Cellular therapies, also known as "stem cell" interventions (SCI), have undergone a rapid popularization in the USA and worldwide. The current review aimed at outlining (1) the ethical challenges facing the implementation of SCI; (2) the applicability of the currently available SCI; and (3) recommendations to achieve ethical, well-regulated incorporation of SCI in the clinical setting. Concerns regarding the inadequate characterization, poor adverse effects disclosure, and unorthodox, often inappropriate, market practices have engendered a genuine concern regarding the SCI compliance with ethical standards. Six instances of litigation on the basis of misrepresentation or inappropriate informed consent were recorded between 2012 and 2018. Such concerns have been furthered by the loopholes in the regulatory aspect governing the use of SCI coupled with the unclear literature-reported efficacy and diverse spectrum of profess indications. Similarly, the application of SCI in the clinical field is yet to prove its value. The uncertain efficacy, coupled with obscure true-costs of utilization, impedes a value-based assessment. A multidisciplinary approach involving legislative and medical professional societies should continue to advance regulations that govern SCI. A well-regulated system that allows for the ethical integration of SCI with appositely evidenced-based described benefits and risks should be sought.
Playing in the FIFA World Cup finals is an ambition shared by several nations. Since, besides luck and skill, the probability of qualification depends on the design of the qualifiers, the study of these competitions forms an integral part of sports analytics. The Confederation of North, Central America and Caribbean Association Football (CONCACAF) announced a novel qualifying format for the 2022 FIFA World Cup in July 2019. However, the COVID-19 pandemic forced the organisers to return to a more traditional structure. The present chapter analyses how this reform impacted the chances of the national teams to qualify. It is found that the probability of participating in the FIFA World Cup finals can change by more than 5 percentage points under the assumption of fixed strengths for the teams. The idea behind the original design, to divide the contestants into two distinct sets, is worth considering due to the increased competitiveness of the matches played by the strongest and the weakest teams. We recommend mitigating the sharp nonlinearity caused by the seeding policy via a probabilistic rule to the analogy of the NBA draft lottery system.
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