Birth Quartile Research Articles

Talent Identification in an English Premiership Rugby Union Academy: Multidisciplinary Characteristics of Selected and Non-selected Male Under-15 Players.

Entry into an academy can be a defining moment for a promising young player. The aim of this study was to explore the multidimensional characteristics that differentiated selected and non-selected male under-15 rugby union players at an English Premiership academy. Seventy-four players (mean age 14.6 ± 0.3 years: selected n = 29; non-selected n = 45) were measured across nine characteristics from four overarching factors: (a) anthropometric (n = 2), (b) physiological (n = 5), (c) cognitive (n = 1), and (d) birth quartile. An ANOVA compared differences between groups (selected vs. non-selected), whilst a Welch's t-test and Cohen's d were used for further comparisons. A multivariate logistic regression was also used to predict selection. Results showed significant differences between selected and non-selected players for anthropometric (P = 0.021) and physiological factors (P < 0.001). Moreover, relatively older players were overrepresented with 65% born in the first half of the year, whereas no significant differences were apparent for the cognitive test. More specifically, selected players possessed greater body mass (P = 0.022, d = 0.5) and handgrip strength (P = 0.020, d = 0.5) compared to non-selected players, whilst multivariate analysis showed the 20 m sprint explained 25.4% of the variance (P = 0.001). Overall, it appears selection into an English Premiership rugby union academy may be due to enhanced physical attributes rather than cognitive abilities.

Relative Age Effect in Canadian Hockey: Prevalence, Perceived Competence and Performance.

The term “relative age effect” (RAE) is used to describe a bias in which participation in sports (and other fields) is higher among people who were born at the beginning of the relevant selection period than would be expected from the distribution of births. In sports, RAEs may affect the psychological experience of players as well as their performance. This article presents 2 studies. Study 1 aims to verify the prevalence of RAEs in minor hockey and test its associations with players' physical self-concept and attitudes toward physical activities in general. Study 2 verifies the prevalence of the RAE and analyzes the performance of Canadian junior elite players as a function of their birth quartile. In study 1, the sample is drawn from 404 minor hockey players who have evolved from a recreational to an elite level. Physical self-concept and attitudes toward different kinds of physical activities were assessed via questionnaires. Results showed that the RAE is prevalent in minor hockey at all competition levels. Minor differences in favor of Q1-born players were observed regarding physical self-concept, but not attitudes. In study 2, data analyses were conducted from the 2018–2019 Canadian Hockey League database. Birth quartiles were compared on different components of performance by using quantile regression on each variable. Results revealed that RAEs are prevalent in the CHL, with Q1 players tending to outperform Q4 players in games played and power-play points. No other significant differences were observed regarding anthropometric measures and other performance outcomes. RAEs are still prevalent in Canadian hockey. Building up perceived competence and providing game-time exposure are examples of aspects that need to be addressed when trying to minimize RAEs in ice hockey.

The Influence of Maturity Status on Anthropometric Profile and Body Composition of Youth Goalkeepers.

The anthropometric profile assessment is an important aspect to consider during the growth stages of youth sport practitioners due to its usefulness in controlling maturity status and overall health. We performed an anthropometric profile evaluation in a sample of youth goalkeepers (n = 42) during a training camp, dividing them into three categories based on their years from peak height velocity (YPHV). We also checked if the selection of goalkeepers was associated with the birth quartile. The results showed that most of the participants’ anthropometric parameters followed the normal trend according to the maturation stages. However, several subjects showed an overweight/obese condition and/or high waist circumference. Non-optimal values were found, mostly in the group of goalkeepers around the PHV. In addition, no selection based on birth quartile was seen. Therefore, the anthropometric profile and body composition of youth goalkeepers are physiologically affected by maturity status. However, several subjects were found to be overweight/obese and at cardiometabolic risk, suggesting that children and adolescents, although practicing sport, should pay attention to potentially contributing factors such as the attainment of the recommended levels of physical activity, lowering sedentary time, and adopt a healthy lifestyle.

Examining the Role of Relative Age on Leadership Behaviours among Female Ice Hockey Players: An Exploratory Investigation

The aim of this study was to examine the influence of relative age on self-reported leadership behaviors among competitive female ice hockey players. Secondary purposes included examining whether a relative age effect (RAE) was present within the sample and if leadership behaviors differed according to leader status (i.e., formal versus informal leaders). Canadian female ice hockey players (ages 15-18 years) completed an online survey that contained the Leadership Scale for Sport along with additional demographic questions. Players were segmented into birth quartiles based upon Hockey Canada’s selection date and classified by leadership status. The MANOVA suggested that the frequency of leadership behaviors displayed by these athletes did not differ across birth quartiles. Furthermore, although there was a RAE trend within this sample of competitive female ice hockey players, the differences relative to population distributions were not statistically significant. Finally, formal leaders (i.e., captains/alternate captains) reported higher levels of social support, positive feedback, democratic behavior, and training and instruction than informal leaders. It appears that relative age is not a discriminating factor with respect to leadership behaviors. Competitive female ice hockey may be an avenue for all players, regardless of their date of birth, to develop and demonstrate leadership.

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.

The relative age effect in Brazilian soccer: so what?

Objectiveː our purpose was a) to describe the Relative Age Effect occurrence in Brazilian elite youth soccer players; b) to identify the association between Relative Age Effect and technical skills and c) to examine how Relative Age Effect can affect Physical Fitness.&#x0D; Method: Eighty-one Brazilian elite soccer players from three age-group teams (U-15, U-17 and U-20) were classified by birth quartiles according to their date of birth. Relative Age Effect was determined when there was a statistically significant difference between players who were born in BQ1 (January through March) to the other birth quartiles (Chi-Square). The association between Relative Age Effect and Technical Rankings was verified by the correlation. The partial correlation controlled for date of birth and for maturity offset was also performed. Relative Age Effect on Physical Fitness was verified by the variance (ANOVA) of its components on each team’s birth quartiles.&#x0D; Results: Players born in BQ1 were the most selected in U-15 (60%) and U-17 (35%) teams, but not in U-20 (25%). A low to moderate (Rho = 0.04 to 0.53) correlation was found between birth quartiles and Technical Rankings, while date of birth and maturation (partial correlation) effects were identified in the U-15 team. Although birth quartiles do not affect Physical Fitness (ANOVA), it may favour some Physical Fitness components (p &lt; 0.05).&#x0D; Conclusions: The greater risk of Relative Age Effect in younger teams is due to the greater emphasis on technical skills. When date of birth and maturation are controlled for, the association between Technical Rankings and birth quartiles is reduced. There was no evidence that Relative Age Effect affected the players’ game performance.

Abstract P105: Associations of Childhood Obesity With Cardiometabolic Risk Factors by Era of Birth: The I3c Consortium

Introduction: The prevalence of childhood obesity has increased dramatically over the past several decades, but it is unclear whether children and adolescents with obesity are experiencing more or fewer cardiometabolic risks from obesity now compared with several decades ago. This study leverages data from over 2600 children and adolescents with obesity born from 1951-1996 to determine whether relationships of obesity with cardiometabolic risk have changed over time. Methods: The first study visit, age 3-19, was used to classify individuals by era of birth (quartiles: 1951-1963, 1964-1969, 1970-1974, 1975-1996), weight status (obesity defined as BMI&gt;CDC 95 th %ile and &lt;120% of the 95 th %ile), high BP (SBP or DBP&gt;95 th %ile), high total cholesterol (TC&gt;170 mg/dl), high LDL-C (&gt;110 mg/dl), high triglycerides (TG&gt;100 mg/dl), high glucose (&gt;100 mg/dl), and low HDL-C (&lt;40 mg/dl males, &lt;50 mg/dl females). Participants with obesity (excluding severe obesity) were included in this analysis. Logistic regressions were adjusted for age, sex, race and study cohort to calculate odds ratios relative to the most recent era of birth (1975-1996). Results: The prevalence of childhood obesity increased from 6.1% in the earliest birth era to 7.7% in the most recent (p&lt;0.0001). The adjusted odds of children with obesity having high TC (p&lt;0.0001), high TG (p&lt;0.0001), and high BP (p=0.003) were half as likely among children born between 1964-69 or 1970-74, compared with the most recent birth era (Table). The odds of children with obesity having high LDL (p=0.59), low HDL (p=0.17) or high glucose (0.33) did not differ across birth eras. Conclusions: Childhood obesity in more recent decades has not only become more prevalent, but is associated with greater risks of high TC, high TG and high BP. However, the risks of high LDL, low HDL and high glucose have not significantly changed among children with obesity who were born between 1951 and 1996. Thus, comparisons of children or adolescents with obesity across eras should consider these differing risk profiles.

The influence of birth quartile, maturation, anthropometry and physical performances on player retention: Observations from an elite football academy

Understanding the factors that influence player retention within elite youth football can be used to enhance current practices. This study investigated an English Category 1 academy to determine if birth quartile, somatic maturity, anthropometric and physical performance characteristics are associated with player retention across the developmental pathway. Birth dates of 355 elite players from Under 11 (U11) to U21 groups were categorised into birth quartiles, and logistic regression (odds ratio) analysis was used to determine the differences in retention. Multilevel modelling compared somatic maturity, anthropometry, countermovement jump, sprint time (10 and 30 m), agility T-test and Yo-Yo Intermittent Recovery Level 1 or 2 performance between retained and dropout players. Logistic regression (odds ratio) analysis revealed no significant differences between birth quartiles for the likelihood of being retained across age groups. Multilevel modelling revealed that retained players were typically older, advanced in maturity and superior in body size and physical performances compared to dropouts, with small to medium effect sizes typically observed. This study indicates that within a highly selective cohort of young football players, somatic maturity, anthropometric and physical performance characteristics, but not birth quartile, distinguish individuals that are subsequently retained or dropout in an age group-dependent manner. Youth football organisations should seek to implement multidisciplinary and dynamic talent selection and retention strategies to prevent inappropriate discrimination and loss of talented young players.

RELATIVE AGE IN FEMALE FUTSAL ATHLETES: IMPLICATIONS ON ANTHROPOMETRIC PROFILE AND STARTER STATUS

ABSTRACT Introduction: Evidence suggests that a higher distribution of elite athletes have birth dates in the first few months of the year. However, the advantages of birth month on performance related to starter status, structure and body composition in female futsal (5-a-side football played on a hard court, mainly indoors), are unknown. Objective: To determine the effect of relative age (ERA) on competitive female futsal athletes, and its influence on anthropometric profile and starter status. Methods: One hundred and fifteen athletes, participants in the 20th Brazilian Cup of Adult Futsal Clubs, special division, were submitted to measurements of body mass, height, skinfold thickness, body perimeters and bone diameters, in order to characterize the anthropometric profile and determine the body somatotype. The athletes were distributed in semesters and quartiles of the months of the year, according to their birth dates. Differences in the distribution of expected and observed birth dates were tested using Chi-square tests (χ2). Comparisons between semesters and birth quartiles were performed using parametric and non-parametric tests. Results: There was no ERA in distribution (p=0.248), anthropometric profile (p=0.872 to 0.912), or starter status between athletes born from January to June (p=0.352) and those born between July and December (p=0.744). On the other hand, those born in the first months of the year showed longer practice times than those born in the latter months of the year. Conclusion: Although the ERA in this study reveals longer practice times favoring female futsal athletes born in the first quartile of the year, it did not influence the starter status, the distribution in the teams, or any advantage in anthropometric profile. Level of evidence III, Case-Control Study.

Youth Developmental Experiences Among Female Hockey Players: The Role of Relative Age

Relative age differences can lead to varying sport participation opportunities; however, scant research has focused on the impact of relative age on experiences within sport. This study explored if youth developmental experiences differed by relative age among competitive female ice hockey players. Players within Ontario (n = 264) completed an online survey that contained the Youth Experience Survey for Sport (YES-S) along with additional demographic questions. The YES-S measures 5 dimensions of positive (i.e., personal and social skills, cognitive skills, goal setting, and initiative) and negative developmental experiences in sport. The results of the multivariate analysis of variance (MANOVA) suggested that the developmental experiences reported by athletes did not differ across birth quartiles (Wilks’ Lambda = 0.940, F (15, 707.105) = 1.061, p = .390). Although there was a relative age effect (RAE) trend within this sample of competitive female ice hockey players, the differences across birth quartiles were not statistically significant. It appears that relative age does not result in youth having different positive and negative sporting experiences. Exploring the characteristics of sport environments (e.g., coaches, practices) and personality traits of competitive athletes to better understand how relatively younger athletes continue their participation in sport despite being at a perceived disadvantage warrants further investigation.

Relative age, maturation, anthropometry and physical performance characteristics of players within an Elite Youth Football Academy

A professional English football club with Category 1 academy status was investigated to determine the magnitude of relative age effects (RAE) within the club and explore between-quartile differences for somatic maturity, anthropometry and physical performances. Birth dates of 426 players from Under 9 to First Team were categorised into four birth quartiles (Q) and examined for relative age effects. Additionally, data on 382 players (Under 11 to First Team) were obtained for somatic maturity, anthropometry, countermovement jump, sprint (10 and 30 m), agility T-test and Yo-Yo Intermittent Recovery Level 1 or 2 performance to determine between-quartile differences. Odds ratios revealed Q1 players were 6.0 times more likely to be represented than Q4 players. Multilevel modelling demonstrated between birth quartile similarities for each variable across all age groups, though there was a tendency for Q4 players to outperform Q1 players between Under 11 and Under 18 groups. Strong relative age effects exist within this club as well as a tendency to select players demonstrating advanced growth and/or maturity, with some indication that higher categorised academies in England may be at risk of amplified selection biases. Talent identification strategies in elite youth football should actively seek to adopt novel approaches to reduce selection biases and avoid wasted potential.

The relative age effect in selection to international team matches in Norwegian handball.

Many elite sport organisations have introduced structured talent identification and development (TID) initiatives in youth sports to better facilitate elite sport performance. However, selection mechanisms for TID programmes (e.g., junior international team) are biased towards relatively older athletes and limited studies exist with Scandinavian contexts. Therefore, the aim of this study was to explore the relative age effect (RAE) in youth, junior and senior male and female international team selections among Norwegian handball players (n = 657). A Chi-square goodness-of-fit test assessed whether a skewed birthdate distribution occurred at the youth, junior and senior international team levels and odds-ratios were calculated for RAE distribution. Moreover, a Kruskal-Wallis test was used to assess differences between the number of international youth, junior and senior level appearances by birth quartiles. Significant uneven birth date distributions were shown for youth (χ2(7) = female 40.383 and male 105.716, p <0.001) and junior (χ2(7) = female 27.427 and male 30.948, p <0.001) international players, favouring the relatively older player (odds-ratio of 1.9–8.3). At the senior level, no uneven distribution was identified. The comparison of the number of matches in each age category and the quartile of birth showed a difference in the women’s youth category, where players in quartile 8 had a significantly lower number of appearances compared to quartile 1. The results form part of a growing body of knowledge about selection mechanisms in sport, which favours relatively older athletes within Norwegian Handball. Such findings are important for policy and practice for informing TID programmes for inclusive selection opportunities for all players.

Relative Age Effect, Biological Maturation, and Coaches’ Efficacy Expectations in Young Male Soccer Players

ABSTRACTPurpose: The talent identification and selection process in young male soccer players is mainly focused on anthropometrics and physical performance, but social factors are also considered in this process. The purpose of this study was to test the existence of the relative age effect and its possible influence on anthropometrics and physical performance and to analyze coaches’ efficacy expectations. Method: Data for 564 young male soccer players (Mage = 13.7 ± 1.5 years; Mweight = 53.7 ± 11.6 kg; Mheight = 160.2 ± 11.6 cm) included their birth quartile, maturity status, anthropometrics, a physical test battery, and coaches’ efficacy expectations. Results: Early-born players were overrepresented (p < .05). Early-born players were not statistically taller, heavier, or better at physical performance (p > .05) when maturation and chronological age were controlled as confounding factors. However, coaches expected more from early-born players (p < .05), and the inferential analysis showed likely to very likely worthwhile differences between the coaches’ expectations for players born in the first quartile of the year and those born in the fourth quartile of the year. Conclusions: Anthropometrical and physical performance variables were not affected by birth quartile, and coaches’ efficacy expectations were related to the relative age effect.

Delayed or on-time? Examining the moderating effect of academic timing on the relative age effect among Canadian interuniversity athletes

ABSTRACTRelative age effects (RAE) are developmental advantages experienced by those born in the initial months after a predetermined cut-off date over their younger counterparts. Student-athletes are considered to be “on-time” when their current year of athletic eligibility coincides with their expected year of athletic eligibility, based on their year of birth. Conversely, student-athletes are considered “delayed” when their current athletic eligibility year corresponds with a younger cohort. This study examined the impact of the RAE and academic timing on participation within nine of the 12 Canadian Interuniversity Sport (CIS) championship sports. A logistic regression was conducted to predict academic timing based on participants’ quartile of birth and sex. The results indicated that males are significantly more likely to be delayed than females, and those student-athletes born in the later months of the year are more frequently delayed compared to their relatively older peers.

Influence of Physical Maturity Status on Sprinting Speed Among Youth Soccer Players

McCunn, R, Weston, M, Hill, JKA, Johnston, RD, and Gibson, NV. Influence of physical maturity status on sprinting speed among youth soccer players. J Strength Cond Res 31(7): 1795-1801, 2017-The relative age effect is well documented with the maturation-selection hypothesis the most common explanation; however, conflicting evidence exists. We observed the birth date distribution within an elite junior soccer academy. The influence of physical maturity status on anthropometric variables and sprinting ability was also investigated. Annual fitness testing was conducted over an 8-year period with a total of 306 players (age: 12.5 ± 1.7 years [range: 9.7-16.6 years]; stature: 156.9 ± 12.9 cm; mass: 46.5 ± 12.5 kg) drawn from 6 age categories (under-11s to under-17s) who attended the same Scottish Premiership club academy. Measurements included mass, stature, maturity offset and 0-15 m sprint. Odds ratios revealed a clear bias toward recruitment of players born in quartile 1 compared with quartile 4. The overall effect (all squads combined) of birth quartile was very likely small for maturity offset (0.85 years; 90% confidence interval [CI], 0.44-1.26 years) and stature (6.2 cm; 90% CI, 2.8-9.6 cm), and likely small for mass (5.1 kg; 90% CI, 1.7-8.4 kg). The magnitude of the relationship between maturity offset and 15-m sprinting speed ranged from trivial for under-11s (r = 0.01; 90% CI, -0.14 to 0.16) to very likely large for under-15s (r = -0.62; -0.71 to -0.51). Making decisions about which players to retain and release should not be based on sprinting ability around the under-14 and under-15 age categories because any interindividual differences may be confounded by transient inequalities in maturity offset.

Exploring the relationship between the relative age effect and youth development among male house league ice hockey players

The current study examined if relative age influences the youth developmental experiences of male house league ice hockey players. Participants completed an on-line survey that solicited their date of birth and responses to the Youth Experience Survey for Sport (YES-S). Our analysis revealed no relative age effect among the house league hockey players. The MANOVA results revealed no significant multivariate differences between quartile of birth and the five YES-S dimensions (p = .493). It is reassuring that the experiences of the house league ice hockey players in our sample do not differ in their developmental experiences as a consequence of when they were born throughout the selection year.

Are the World Junior Championship Finalists for Middle- and Long-Distance Events Currently Competing at International Level?

To analyze how many finalists of the International Association of Athletics Federations (IAAF) World Junior Championships (WJCs) in the middle- and long-distance track events had dropped out from high-level competitions. Starting from 2002, the 8 male and the 8 female finalists in the middle- and long-distance events of 6 editions of the WJC were followed until 2015 to evaluate how many missed the IAAF rankings for 2 consecutive years starting from the year after WJC participation. For those still competing at elite level, their careers were monitored. In 2015, 61% of the 2002, 54.8% of the 2004, 48.3% of the 2006, 37.5% of the 2008, 26.2% of the 2010, and 29% of the 2012 WJC finalists were not present in the IAAF rankings. Of the 368 athletes considered, 75 (20.4%) were able to achieve the IAAF top 10 in 2.4 ± 2.2 y. There is evidence of relationships between dropout and gender (P = .040), WJC edition (P = .000), and nationality (P = .010) and between the possibility to achieve the IAAF top 10 and dropout (P = .000), continent (P = .001), relative age effect (P = .000), and quartile of birth (P = .050). Even if 23 of the finalists won a medal at the Olympic Games or at the World Championships, it is still not clear if participation at the WJC is a prerequisite to success at a senior level.

Large Scale Analysis of Relative Age Effect on Professional Soccer Players in FIFA Designated Zones

The aim of this study was to analyse the occurrence and the magnitude of the Relative Age Effects (RAEs) in professional soccer players, and whether this effect is different depending on their position, the leagues where they play, the level of the competition, the level of the team in which they play and their nationality. The sample was composed by 12,144 professional players who participated in the professional leagues during the 2014-2015 season. The date of birth of each player was classified into four birth quartile (Q1, Q2, Q3 and Q4). Most professional soccer players are in the nearest quartiles at the beginning of the selection year, resulting in a decrease in birth as far as furthest quartiles are concerned. The RAE was found in the first (Effect Size= small) and second division (ES=medium) of competitions and in all the leagues analysed, except in the Premier League (England) and the K-League Classic (South Korea). Moreover, all playing positions (goalkeeper, defender, midfielder and forward) in soccer was affected by RAEs. In order to reduce RAE several solutions have been proposed by scientific literature that may be adopted by coaches and soccer clubs (i.e. greater number of categories, rotate court dates, or establish technical-coordinative reference values per quartile of birth).

Does Relative Age Affect Career Length in North American Professional Sports?

BackgroundRelative age effects (RAEs) typically favour older members within a cohort; however, research suggests that younger players may experience some long-term advantages, such as longer career length. The purposes of this study were to replicate previous findings on RAEs among National Hockey League (NHL) ice hockey players, National Basketball Association (NBA) basketball players and National Football League (NFL) football players and to investigate the influence of relative age on career length in all three sports.MethodsUsing official archives, birthdates and number of games played were collected for players drafted into the NBA (N = 407), NFL (N = 2380) and NHL (N = 1028) from 1980 to 1989. We investigated the possibility that younger players might be able to maximize their career length by operationalizing career length as players’ number of games played throughout their careers.ResultsThere was a clear RAE for the NHL, but effects were not significant for the NBA or NFL. Moreover, there was a significant difference in matches played between birth quartiles in the NHL favouring relatively younger players. There were no significant quartiles by career length effects in the NBA or NFL.ConclusionsThe significant relationship between relative age and career length provides further support for relative age as an important constraint on expertise development in ice hockey but not basketball or football. Currently, the reason why relatively younger players have longer careers is not known. However, it may be worth exploring the influence of injury risk or the development of better playing skills.

Investigating the relationship between the relative age effect and leadership behaviors among male ice hockey players

This study examined the role of relative age on leadership behaviors among male house league ice hockey players. Athletes completed an online survey that solicited their birthdate along with their responses to the leadership scale for sport. As expected, the results of our analyses revealed no relative age effects. Captains scored significantly higher on the training and instruction, democratic behavior and social support dimensions of the leadership scale for sport. While there were significant multivariate differences between birth quartile and the dimensions of leadership, a relative weight analysis revealed that quartile of birth did not differ significantly on any of these dimensions. Thus, male house league hockey players are not (dis)advantaged in terms of their leadership behaviors as a consequence of relative age.