Background: Studies have shown that children and adolescents who are relatively older than their younger peers have advantages in sports, partly because they are more biologically mature, a relative age effect (RAE). However the occurrence of RAE in physical performance is still somewhat unclear and more knowledge is needed. Aim: The aim of this study was to investigate if there were any RAEs on anthropometric measures and physical performance in adolescents who are 13 years old and active in sports. Methods: 128 subjects (78 boys, 50 girls) from Malmö idrottsakademi, a school with a sports profile, were included in this study. Measurements of height and weight were taken and the physical performance was tested for grip strength, sprint and countermovement jump (CMJ). To analyse RAEs the subjects were divided into three groups (teriles) according to their month of birth. Subjects born in Tertile 1 (Jan-Apr) and Tertile 3 (Sep-Dec) were compared together as well as within and between the sexes with independent t-tests. Results: RAEs were present in height (p=0.01), weight (p=0.01), and grip strength (0.03) where higher values were found in the relatively older subjects. Additionally, if weight was accounted for, RAE was present in CMJ where the relatively younger subjects performed better (p=0.03). Further, when sexes was analysed separately the older boys were taller (p=0.01), heavier (p=0.02), and stronger (p=0.05) compared with the younger boys. The older girls were heavier (p=0.01) compared with the younger girls whereas the younger girls got a higher CMJ weight ratio (p=0.05). Conclusion: RAEs were found on anthropometric measures, but were less clear in physical performance. This indicates that although relatively older adolescents are taller and heavier, they are not always in advantage over their younger peers regarding physical performance.

Syfte och frågeställningar: Studiens huvudsakliga syfte var att undersöka vilka elever som går på Sveriges elitinnebandygymnasier efter reformen av den gymnasiala idrottsutbildningen.Ytterligare ett syfte var att urskilja påverkansfaktorer i utvecklingsprocessen som innebandyspelare.- Hur ser förekomsten av relative age effect ut på elevpopulationen?- Hur upplever eleverna sina förväntningar och egna förmåga i sitt innebandyutövande?- Hur ser elevernas idrottsbakgrund ut? Metod: Enkätundersökning har använts som metod i denna studie. Totalt har 132 elever på Sveriges elitinnebandygymnasier besvarat enkäten. Könsfördelningen var 46 flickor och 86 pojkar. Enkäten bestod av både öppna och slutna frågor där eleverna fick besvara frågor som rörde deras idrottande idag samt idrottsbakgrund. Resultat: Elevernas födelsefördelning var spridd sett till hela populationen. Bland pojkarna på Riksidrottsgymnasiet var 58 % födda under det första kvartalet och visade på en relative age effect. Majoriteten av eleverna började spela innebandy i tidig ålder, innan nio års ålder. Utöver innebandy hade över 90 % av eleverna sysslat med flera andra idrotter under sin uppväxt, men de flesta hade nu specialiserat sig på innebandy. Bland eleverna strävade 94 % mot elitnivå, majoriteten tränade innebandy mellan 7-12 timmar/vecka. Pojkarna tränade, i större utsträckning, mer än flickorna. En stor majoritet bland flickorna och ungefär 60 % bland pojkarna hade deltagit i SDF-SM för femtonåringar. Eleverna angav att de hade höga krav på sig själva som generellt var högre än de krav de upplevde utifrån. Det var en stor spridning på hur eleverna uppfattade sin egen förmåga jämfört med sina lagkamrater. Det var dock väldigt ovanligt att eleverna inte alls tyckte sig tillhöra, eller att de tidigare tillhört, de bästa i laget. Slutsats: Den nya gymnasiereformen har påverkat idrottsutbildningarna där en intensifierad elitsatsning införts. Denna studie fokuserade på innebandygymnasierna och vi kan konstatera att eleverna delade utbildningens elitambition. Vad de långsiktiga effekterna kommer bli är omöjligt att säga men säkert är att den elitistiska inriktningen på ett eller annat sätt kommer påverka eleverna. Forskningen är fortfarande tudelad om vilka effekter en tidig elitsatsning har och om vilken väg som är den bästa för framtidens elitspelare. Efter att ha genomfört denna studie kunde vi konstatera att majoriteten av eleverna har en bred idrottsbakgrund och relativt sent specialiserat sig på en idrott.

Syfte Syftet med studien var att undersöka om relative age effect förekommer på svenska längdskidgymnasier bland antagna elever och hur eventuell förekomst ser ut bland flickor och pojkar samt hur det ser ut vid Riksidrottsgymnasierna och de Nationell Idrottsutbildningarna. Metod För att besvara syftet har statistisk data analyserats med hjälp av ett Pearson Chi2-test. Analysen har skett genom att undersöka födelsemånad, kön och inriktning bland antagna elever vid svenska längdskidgymnasier mellan åren 2010-2015. Resultat Resultatet visar att det finns signifikanta bevis på att relative age effect förkommer på svenska längdskidgymnasier (p= <0,05). Vid uppdelning av respektive utbildningsinriktning kunde det endast konstateras förekomst av relative age effect vid Riksidrottsgymnasierna, vid uppdelning av kön går det inte att säkerställa en signifikant förekomst av relative age effect. Slutsatser Studiens resultat visar att det förekommer relative age effect på svenska längdskidgymnasier, dock varierar den mellan de analyserade undervariablerna. Tydligast förekommer relative age effect vid Riksidrottsgymnasierna, medan det vid Nationell Idottsutbildning, kunde det inte konstateras bevis för en signifikant överrepresentation av elever födda under första kvartalet. När flickor och pojkar analyserades separat kunde ingen relative age effect konstateras. Det behövs mer forskning inom området för att få en överblick av konsekvenserna av relative age effect på längdskidgymnasier men även konsekvenserna för svensk längdskidåkning i stort. / Aim The purpose of this study was to investigate if relative age effect occurs at Swedish cross-country ski schools and if there were a differences in the presence among boys and girls, and between Riksidrottsgymnasier (Country-wide sport academy) and Nationell Idrottsutbildning (National sport academy). Method To answer the aim, statistical data were analyzed using a Pearson Chi2-test. The analysis has been done by examining birth month, sex and education among students at Swedish cross-country ski schools between 2010-2015. Results The result shows that there is a significant evidence of relative age effect at Swedish cross-country ski schools (p= <0,05). When the results were partial between Riksidrottsgymnasier and Nationell Idrottsutbildning, the relative age effect was only seen at Riksidrottsgymnasierna. There were no significant evidence for relative age effect when boys and girls where analyzed separately. Conclusion The results show that relative age effect appears on Swedish cross-country ski schools; however, there were some varies between analyzed variables. Strongest evidence for relative age effect was seen at Riksidrottsgymnaiserna. Further research is needed to get a overview of the consequences of relative age effect at cross-country ski schools, and the consequences it has in Swedish cross-country skiing overall, both for younger and older skiers.

Schools and sports governing bodies have added physical literacy in their curricula. However, until recently, there was no validated protocol to assess children’s physical literacy progress. In response to this need, the Canadian Assessment of Physical Literacy (CAPL) was developed; it measures physical literacy by assessing 4 important domains (physical competence, daily behaviours, motivation and confidence, and knowledge and understanding). The relative age effect (RAE) bias is attributable to age grouping by the imposition of cut-off dates; this age grouping strategy is common in sports and schools. However, despite its objective of providing age-adjusted learning, it promotes a relative age difference that leads to a developmental advantage for children born just after the cut-off date. Analogous to the age grouping in schools and sports, the CAPL protocol uses rounded-down age bands to objectively compare children; however, this type of comparison is also known for being susceptible to the RAE bias. The purpose of this thesis was to determine whether the RAE bias was associated with the CAPL scores (i.e., the four domains individually and the overall score) and all of the physical competence domain assessments individually (anthropometrics, aerobic, strength, muscular endurance, flexibility and movement skills). Participants (n=8,233, 50.2% girls), ages 8 to 12 years, from 7 provinces were tested using the CAPL protocol. Analyses of covariance (controlling for age, testing date, body mass index z-scores and testing sites) revealed a significant RAE bias in boys in 2 out of the 4 domains (physical competence and knowledge and understanding domains) and in girls in 3 out of the 4 domains (physical competence, knowledge and understanding and motivation and confidence domains). However, these significant associations between domain scores and relative age yielded negligible effect sizes, thus no meaningful RAE was observed. Collectively, the results of this thesis suggest that the RAE should not affect the validity of the CAPL in accurately measuring physical literacy.

I en allt mer elitsatsande idrott skapas fler och fler svårigheter och problem. Ett av dessa är relative age effect (RAE). RAE innebär att det finns en överrepresentation i deltagarpopulationen av deltagare som är födda tidigt på året. Anledningen till detta problem befattas av fler olika anledningar men det som främst brukar förklara fenomenet är den eventuella skillnaden i biologisk mognad mellan idrottande ungdomar. Fenomenet har tidigare visat stor närvaro i ungdomsidrotten och i vissa delar av senioridrott också. Dock har större delarna av studierna som gjorts på olika sporter bara analyserat ungdom- eller herrfotboll. Där av denna studiens fokus på elitdamfotboll. Syftet med studien är att analysera förekomsten av relative age effect i damallsvenskan under säsongen. Två frågeställningar, med inriktning mot födelsekvartil och olika deltagande nivåer, testades på spelare i damallsvenskan under säsongen 2018. Studien innefattade även en jämförelsepopulation för att kunna se om det finns en snedfördelning av deltagare utifrån den nationella befolkningen av kvinnor i Sverige. Första frågeställningen riktade in sig på att analysera fördelningen av spelare i olika kvartil utifrån den förväntade fördelningen som jämförelsepopulationen bidrog med. Den andra frågeställningen syftade på att analysera spelarnas fördelning utifrån deras födelsekvartil och hur många matcher de spelade under säsongen. Båda frågeställningarna använde metoden Chi2-tester för att få fram ett resultat som kan bevisa om relative age effect existerar i de analysera grupperna. Båda frågeställningarna resulterade i att det inte fanns bevis för relative age effect inom något område i damallsvenskan säsongen 2018, varken utifrån fördelningen av antalet spelare i födelsekvartilen eller utifrån antalet spelade matcher. Det fanns in heller några statistiskt signifikanta skillnader mellan de individuella kvartilen. / In an increasingly competitive sports world more and more problems and difficulties develop. One of these is relative age effect (RAE). RAE implies that there is an overrepresentation of participants in a population that are born early in the year. The reason for this problem depends on many different reasons but the most usual reason for explaining the phenomenon is the possible differences in biological maturity between sporting youths. The phenomenon has previously shown a large presence in youth sports and for some cases in adult sports as well. But the dilemma is that most of the studies done are on either youth- or adult sports. Therefor this study is focused on highly competitive women’s soccer. The aim of this study is to analyze the presence of relative age effect in damallsvenskan in the season of 2018. Two questions of the issue, one focused on birth quartiles and the other focused on participation levels, was tested on players from the 2018 season in the damallsvenskan. The study includes a comparison population aimed to se if there is an uneven distribution of participants based on the national population of women in Sweden. The first question of the issue is aimed to analyze the distribution of players in different quartiles in comparison to the comparison population. The second question of the issue aimed at analyzing distribution of players based on their birth quartiles and the amount of games played during the season. Both questions of the issue used the method Chi2-tests for getting a result that could show if relative age effect exists in the analyzed groups. Both resulted in showing that there was no evidence for relative age effects existence in 2018 season of damallsvenskan, not in the distribution of players birth quartiles or in the distribution based on amount of games played. There wasn’t a statistically significand difference between the individual quartiles either.

Syfte Syftet med denna uppsats är att identifiera skillnader mellan manliga professionella svenska ishockeyspelare från säsongen 2017/2018 när det handlar om deltagande inom TV-pucken, ungdoms och juniorlandslag samt studier vid RIG. Vidare avses att undersöka Relative Age Effect (RAE) med syfte att identifiera födelsekvartal bland individerna. Metod I detta arbete har en statistisk analys utförts. Informationen har inhämtats från diverse hemsidor. Eliteprospects och SCB är arbetets största informationskällor. Tillvägagångsättet har bestått av en kvantitativ metod där statistik inhämtats och bearbetats samt kategoriserats, vidare har Chi2-tester genomförts för att undersöka om det fanns statistiskt signifikanta skillnader mellan grupperna. Resultat Utifrån en kvantitativ undersökning har resultat angående skillnaderna när det handlar om deltagande inom TV-pucken, ungdoms- och juniorlandslag samt studerande vid RIG tagits fram. Utifrån resultaten syns att NHL är den liga som har flest deltagare inom de sammanhang som undersökts procentuellt. Vidare har SHL en större procentandel som deltagit i sammanhangen än vad HA har förutom i TV-pucken där ligorna i princip är likvärdiga. Frågeställningen kring RAE visar att det finns indikationer på att det förekommer i SHL samt HA, dock inte i NHL bland spelarna i urvalsgruppen. Även genomfördes Chi2 tester som utgått från signifikansnivån 0.05 med ett critical value på 7,82 samt 3, 84 beroende på om det använts fyra eller två variabler i uträkningen. Av femton tester har åtta tester varit statistiskt signifikanta i skillnaderna mellan grupperna som jämförts. Slutsatser Utifrån resultaten som tagits fram är det tydligt att det finns statistiskt signifikanta skillnader mellan ligorna som undersökts. För att nå professionell nivå är det en tydlig fördel att delta i TV-pucken, ungdoms- och juniorlandslag samt studera vid RIG, framförallt om sannolikheten för att ha möjlighet att spela i NHL ska vara hög. Även syns tecken på RAE i SHL och HA, dock skulle en studie med ett större urval där fler idrotter involveras ge möjlighet att generalisera kring hur åldersfördelning ser ut inom professionell idrott generellt. / Purpose The purpose with this essay is to identify the differences between professional Swedish male hockey players from the 2017/2018 season which have played in the NHL, SHL and HA. The compression consists of looking at the differences in participation concerning TV-pucken, youth- and junior national-teams and studies at RIG. Furthermore, it refers to explore if there is any sign of Relative Age Effect (RAE) among the participants. Methods In this essay a statistical investigation has been done. The information has been collected from different websites with open registers. Eliteprospects and SCB is the biggest sources of information for the investigation. Results By a quantitative investigation concerning participation in TV-pucken, youth-and junior national-teams and studies at RIG results has been produced. From that it´s visible that the NHL is the league which have the most participants in the examined contexts based on percentage. Furthermore, the SHL have a bigger percentage which have participated in the examined contexts then HA, with exception for TV-pucken where the results where similar. The issue concerning RAE shows indications of it in SHL and HA, but not in the NHL when looking at the selected group. Also, performed where Chi-2 tests that where compared to a significance level of 0.05 which means a critical value of 7,82 or 3,64 depending on if two or four variables parted in the calculation. Out of fifteen tests, eight of them showed out to be statistically significant. Conclusion By the results which have been brought out its visible that there are statistical significant differences between the examined leagues. To be able the reach professional level there is a clear advantage to participate in the examined contexts, especially if a possibility to play in the NHL will appear. Also, it shows signs of RAE in the SHL and HA, though a study on a larger group of individuals performing different sport would give the possibility to generalize the group of professional athletes.

Ice hockey is one of the most popular sports in Sweden. Despite its small population, Sweden is one of the most successful ice hockey nations in the world. But who gets the chance to play on the highest level? and what determines this? North American and German studies have shown that birth date, and wherea player grew up, can have an influence on player development. The purpose of the study was to increase the knowledge of the factors that influence selected 15-year-old ice hockey players' way to the elite level. This study had a qualitative approach and the data was collected from a large database. The study included 2303 players born in 1985, 1987, 1989, 1991 and 1994 whom either had played the Swedish tournament TV-pucken or have established themselves as elite hockey players. The result showed that playing for an elite club and growing up in a large region increased the chance for a player to play on elite level. A reverse RAE appeared in this study, players who was born in the third or fourth quarter of the year had increased chances to play at elite level. The conclusion is that this study contributes to adeeper understanding on selection, the reversed RAE and how the chances increase if you are born in the right place and play for the right club.

Syfte Syftet med studien är att undersöka fem lärares syn på talangidentifikation, hur de realiserar uttagningsprocessen till NIU samt hur de förhåller sig till relativ ålderseffekt (RAE) i uttagningsprocessen. Frågeställningarna vi ämnar att besvara är: Hur ser lärarna på talangidentifikation? Hur realiseras uttagningsprocessen vid NIU och vilka utmaningar ser lärarna med uttagningsprocessen? Vilken kunskap har, och hur förhåller sig lärarna till RAE vid uttagningsprocessen? Metod 
 Metoden som använts är kvalitativ och genomförs med hjälp av semi-strukturerade intervjuer. Målet med våra intervjuer att ta reda på hur lärarna upplever uttagningsprocessen samt deras förhållningssätt i arbetet med RAE. Anledningen till den kvalitativa karaktären är att vi har ett område vi vill kartlägga samt samla djupare information om, i detta fall RAE i samband med uttagning till NIU. Urvalet bestod av fem lärare; lärare 1, lärare 2, lärare 3, lärare 4 och lärare 5 som alla hade olika erfarenheter av läraryrket och arbetet med NIU Resultat
 Studiens resultat visar att det finns skillnader mellan de lärare som är involverade i individuella idrotter kontra lagidrotter i vad man anser att en talang bör besitta för egenskaper. För de lärare, lärare 3 och 4 som representerade individuella idrotter framgick det att den idrottsspecifika kunskapen vägde tyngst vid identifiering av en talang och att denna identifiering redan kan göras vid en tidig ålder. Lärare 1,2 och 5 som representerade lagidrotter lade en stor vikt vid att en talang måste besitta psykologiska färdigheter för att kunna identifieras som talang. Vidare visar resultatet att uttagningen är en rättsosäker process där uttagningarna ser olika ut beroende på idrott och i vissa fall skola. Gällande svårigheter med uttagningsprocessen och vad de värderade kom likartade svar fram i form av att de var rädda för att välja bort någon som senare skulle utvecklas. Vid frågan om värdering kom ord som drivkraft och målmedvetenhet fram. Samtliga av de intervjuade lärarna nämner inte att de aktivt tar hänsyn till relativ ålderseffekt i uttagningsprocessen. Lärare 2 och 5 är de lärare som lyfter att de tar hänsyn till den fysiska mognaden i uttagningen men inte vilken tid på året de elever som ansöker till NIU är födda på. Slutsats Studiens resultat belyser ett problem som finns i och med den rättsosäkerhet som råder vid uttagningsprocessen till NIU. Studien visar även att lärarna har olika uppfattning om vad talang är och hur talang identifieras. Resultatet visade att RAE är utbrett fenomen men något som inte tas hänsyn till i uttagningsprocessen till NIU. / Aim The aim of this study is to examine how five teachers view talentidentification, how they execute the tryout process to elite academy schools and also how they relate to relative age effect(RAE) in the tryout process. The questions being answered in this study are: 1. How do the teachers view talentidentification? 2. How is the tryout process being performed and what difficulties do the teachers experience with the tryout process? 3. What knowledge do the teachers have in regards to RAE and how do they relate to RAE during the tryout process? Method The method being used is qualitative and is executed by performing semi-structured interviews. The purpose of our interviews is to examine how the teachers experience the tryout process and their approach when working with RAE. The reason for the explorative nature is because we have an area to survey and also gather deeper information about, in this case, RAE in relationship to the tryout process to elite academy schools. The selection consisted of five teachers (teacher 1, teacher 2, teacher 3, teacher 4 and teacher 5) that all had different experiences of working as a teacher and with elite academy school. Results The result showed that there are differences among teachers involved in individual sports in relation to teachers working with team sports, in regards to what kind of attributes a talent should possess. For the teachers, teacher 3 and teacher 4, which represented individual sports it appeared that sport specific knowledge was most important when identifying a talent. This identification can be performed at an early age. Teacher 1, 2 and 5 which represented team sports stressed the importance of the psychological skills that a talent must possess, in order to be identified as a talent. The result also showed that the tryouts is an equivocal process where the tryouts is executed differently depending on the sport and in some cases which school. In regards to difficulties with the tryout process and what the teachers valued similar responses were received. All teachers described the fear of eliminating someone who could possibly develop late and they all valued attributes as drive and dedication. All teachers also mention that they do not take RAE in consideration during the tryout process. Teachers 2 and 5 mention taking the physical development into consideration during the tryout process, however not which month a student applying is born. Conclusions This study brings up a problem that is very current due to the equivocality which is present during the tryout process to elite academy schools. The study also showed that the teachers had different opinions in regards to what talent is and how to identify it. The result showed that RAE is a rife phenomenon however it is not being taking into consideration during the tryout process to elite academy schools.

O estágio maturação biológica é um fator importante que influencia o processo de seleção e promoção de talentos esportivos. Vários autores têm demonstrado que diferentes aspectos morfofuncionais, como por exemplo, o tamanho corporal, a velocidade e a força, possuem um ritmo de desenvolvimento individual durante o período da puberdade, sendo altamente dependente do estágio de maturação biológica. Diante dessa influência da maturação biológica sobre o processo de seleção de jovens atletas, outro fenômeno vem sendo observado durante esse processo, o Efeito da Idade Relativa (EIR). O EIR refere-se à influência que os meses de nascimento (idade cronológica) podem provocar na aprendizagem e no desempenho de jovens em uma determinada tarefa e/ou processo ensino-aprendizagem. Portanto, seguindo o pressuposto do EIR, os sujeitos nascidos nos primeiros trimestres do ano poderiam apresentar vantagens biológicas (ex. hormônios), físicas (ex. estatura, peso, força, etc.), cognitivas, psicológicas e de aprendizagem sobre sujeitos de mesma idade cronológica nascidos nos últimos meses do ano. Essas variações poderiam afetar o desempenho, provocando a superestimação dos resultados observados no momento da avaliação. Desta forma, o objetivo do presente estudo foi analisar a maturação biológica e o EIR entre os jovens atletas selecionados para programas de treinamento em longo prazo no futebol. Para tanto, em um primeiro momento foram avaliados jovens atletas de futebol, participantes do processo de seleção de talentos para ingresso na categoria sub-14 de um clube de futebol com destaque nacional e internacional. No segundo momento foram coletadas as mesmas variáveis apenas no grupo de jovens selecionados para compor a equipe sub-14 do referido clube. Os parâmetros avaliados foram: mês de nascimento, nível de maturação sexual, concentração de testosterona, composição corporal e força geral (preensão palmar). De maneira geral, os resultados permitiram concluir que há uma forte presença do EIR na amostra investigada de jogadores de futebol apresentando diferentes datas de nascimento entre iniciantes/titulares e excluídos, com maior participação de jogadores nascidos no primeiro trimestre no grupo de iniciantes/titulares (75%) quando comparados ao grupo selecionado (50%). Também foi detectada uma concentração de testosterona mais elevada para os jogadores selecionados (172,0 ± 43,1 nmol.L-1) em comparação com os jogadores excluídos (130,3 ± 28,3 nmol.L-1). Portanto, os achados atuais sugerem uma forte influência do EIR e da maturação biológica no processo de seleção de jovens jogadores de futebol / The biological maturation status is an important factor that influences the talent identification process and development of sports talent. Several authors have shown that different morphological and functional aspects, such as body size, speed and strength have an individual rate of development during puberty, being highly dependent on the stage of sexual maturation. Given this influence of biological maturation on the talent identification process of young athletes, another phenomenon has been observed during this process, the Relative Age Effect (RAE). The RAE refers to the influence that the months of birth (chronological age) can result in learning and performance of a given task in young people. Therefore, following the assumption of the RAE, subjects born in the first quarters of the year could provide biological advantages (eg. hormones), physical (eg. height, weight, strength, etc.), cognitive, psychological and learning about the same subject chronological age born in the last months of the year. These variations could affect performance, causing overestimation of the results observed during the talent identification process. Thus, the objective of this study is to analyze the biological maturation and RAE between young athletes selected for training programs in football long term. Therefore, in the first instance will be assessed youth soccer players participating in the talent selection process for entry into the under-14 category of a football club, with national and international prominence. In the second phase will be collected the same variables in the group of young people selected to make the under-14 team of the club. The parameters are: month of birth, level of sexual maturity, testosterone, body composition, and overall strength (grip hand). In general, the results allowed to conclude that there is a strong presence of EIR in the sample investigated of soccer players showing a different birth date distribution was observed between starters and dismissed players with a greater participation of players born in the first trimester in the starters group (75%) when compared to the selected group (50%). Also a higher testosterone concentration was detected for starters players (172.0 + 43.1 nmol.L-1) as compared to dismissed players (130.3 + 28.3 nmol.L-1). Therefore, current findings suggest a strong influence of EIR and biological maturation on the selection process of young soccer players

O estágio maturação biológica é um fator importante que influencia o processo de seleção e promoção de talentos esportivos. Vários autores têm demonstrado que diferentes aspectos morfofuncionais, como por exemplo, o tamanho corporal, a velocidade e a força, possuem um ritmo de desenvolvimento individual durante o período da puberdade, sendo altamente dependente do estágio de maturação biológica. Diante dessa influência da maturação biológica sobre o processo de seleção de jovens atletas, outro fenômeno vem sendo observado durante esse processo, o Efeito da Idade Relativa (EIR). O EIR refere-se à influência que os meses de nascimento (idade cronológica) podem provocar na aprendizagem e no desempenho de jovens em uma determinada tarefa e/ou processo ensino-aprendizagem. Portanto, seguindo o pressuposto do EIR, os sujeitos nascidos nos primeiros trimestres do ano poderiam apresentar vantagens biológicas (ex. hormônios), físicas (ex. estatura, peso, força, etc.), cognitivas, psicológicas e de aprendizagem sobre sujeitos de mesma idade cronológica nascidos nos últimos meses do ano. Essas variações poderiam afetar o desempenho, provocando a superestimação dos resultados observados no momento da avaliação. Desta forma, o objetivo do presente estudo foi analisar a maturação biológica e o EIR entre os jovens atletas selecionados para programas de treinamento em longo prazo no futebol. Para tanto, em um primeiro momento foram avaliados jovens atletas de futebol, participantes do processo de seleção de talentos para ingresso na categoria sub-14 de um clube de futebol com destaque nacional e internacional. No segundo momento foram coletadas as mesmas variáveis apenas no grupo de jovens selecionados para compor a equipe sub-14 do referido clube. Os parâmetros avaliados foram: mês de nascimento, nível de maturação sexual, concentração de testosterona, composição corporal e força geral (preensão palmar). De maneira geral, os resultados permitiram concluir que há uma forte presença do EIR na amostra investigada de jogadores de futebol apresentando diferentes datas de nascimento entre iniciantes/titulares e excluídos, com maior participação de jogadores nascidos no primeiro trimestre no grupo de iniciantes/titulares (75%) quando comparados ao grupo selecionado (50%). Também foi detectada uma concentração de testosterona mais elevada para os jogadores selecionados (172,0 ± 43,1 nmol.L-1) em comparação com os jogadores excluídos (130,3 ± 28,3 nmol.L-1). Portanto, os achados atuais sugerem uma forte influência do EIR e da maturação biológica no processo de seleção de jovens jogadores de futebol / The biological maturation status is an important factor that influences the talent identification process and development of sports talent. Several authors have shown that different morphological and functional aspects, such as body size, speed and strength have an individual rate of development during puberty, being highly dependent on the stage of sexual maturation. Given this influence of biological maturation on the talent identification process of young athletes, another phenomenon has been observed during this process, the Relative Age Effect (RAE). The RAE refers to the influence that the months of birth (chronological age) can result in learning and performance of a given task in young people. Therefore, following the assumption of the RAE, subjects born in the first quarters of the year could provide biological advantages (eg. hormones), physical (eg. height, weight, strength, etc.), cognitive, psychological and learning about the same subject chronological age born in the last months of the year. These variations could affect performance, causing overestimation of the results observed during the talent identification process. Thus, the objective of this study is to analyze the biological maturation and RAE between young athletes selected for training programs in football long term. Therefore, in the first instance will be assessed youth soccer players participating in the talent selection process for entry into the under-14 category of a football club, with national and international prominence. In the second phase will be collected the same variables in the group of young people selected to make the under-14 team of the club. The parameters are: month of birth, level of sexual maturity, testosterone, body composition, and overall strength (grip hand). In general, the results allowed to conclude that there is a strong presence of EIR in the sample investigated of soccer players showing a different birth date distribution was observed between starters and dismissed players with a greater participation of players born in the first trimester in the starters group (75%) when compared to the selected group (50%). Also a higher testosterone concentration was detected for starters players (172.0 + 43.1 nmol.L-1) as compared to dismissed players (130.3 + 28.3 nmol.L-1). Therefore, current findings suggest a strong influence of EIR and biological maturation on the selection process of young soccer players