In the selection of young athletes, earlier-born adolescents often leverage their temporary biological advantage over their later-born peers from the same cohort, giving rise to the phenomenon known as the Relative Age Effect (RAE). In this study, we delved into the complexities of the RAE in soccer by reviewing 563 independent research samples across 90 articles. Our analysis showed that age period and performance level are pivotal factors influencing the magnitude of the RAE. The adolescent age period emerged as a significant RAE determinant, showcasing the highest effect size magnitudes in our findings. Among athletes of different performance levels, adult European soccer players have been extensively studied, and they have exhibited the most pronounced RAE magnitudes. Intriguingly, our findings reveal another compelling trend: the frequency of players born early versus late in the eligible birth year escalated as player performance levels increased, particularly during adolescence. Coaches and players appear to capitalize unconsciously on this maturational advantage, though this strategy wanes post-adolescence. While there are currently no penalties for this team selection practice, our findings stress the need for coaches to comprehend the ramifications of selecting athletes with an age bias We offer insights into RAE complexities, highlight the synergy of age and performance in these transitory advantages, and advance arguments for more fairly selecting and developing youth athletes.
[Relative Age effect in Czech orienteering runners]
Fenomén relativního věku (Relative Age Effect, RAE) silně ovlivňuje sportovní vývoj mládeže. RAE odkazuje na neúměrně vysoké procento sportovců narozených na začátku kalendářního (selekčního) roku ve sportovních výběrech. V posledních letech došlo k nárůstu studií týkajících se této problematiky i v méně populárních sportech. Počet studií v těchto sportech často není dostatečný což znemožňuje komplexní pochopení problematiky RAE. Cílem předložené studie bylo zjistit přítomnost RAE u nejlepších orientačních běžců a běžkyň (n = 469) v kategoriích žáků, dorostenců a juniorů (věkové kategorie U12–U20) v České republice. Potřebná data byla získána z informačního systému orientačního běhu (ORIS). Podle data narození byli běžci a běžkyně zařazeni do jednotlivých čtvrtletích (Qi) a půlroků (Si). Výsledná data byla porovnávána s očekávanými daty pro jednotlivé části roku. Analýza byla provedena za pomoci Chi-kvadrát testu (χ2 test) ve verzi testu dobré shody (Goodness-of-Fit). Výsledky ukázaly, že v celém zkoumaném souboru se narodilo více běžců a běžkyň ve druhé polovině roku. Obdobně tomu bylo i v jednotlivých kategoriích, s výjimkou kategorií U16 a U18. V kategorii U16 bylo více sportovců narozeno v první polovině roku, což byla jediná výjimka, a v kategorii U18 bylo rozložení dat narození v rámci půlroků vyrovnané. V celém zkoumaném souboru a v žádné jednotlivé kategorii však nebyla potvrzena statistická významnost výsledků (p > 0,05). Dosáhnuté výsledky mohou být ovlivněny několika faktory: jeden z těchto faktorů je pravděpodobně skutečnost, že se jedná o neolympijský sport a v České republice je stále poměrně okrajový. Z tohoto důvodu se zdá, že vlivy, které podporují RAE, nejsou tak výrazné, aby se významně projevily na přítomnosti tohoto fenoménu.
The Relative Age Effect (RAE) is a phenomenon that strongly affects the sports development of youth. RAE refers to the disproportionately high percentage of athletes born at the beginning of the calendar (selection) year in sports selections. In recent years, there has been an increase in studies related to this issue, even in less popular sports. The number of studies in these sports is often insufficient, which hinders a comprehensive understanding of the RAE issue. The aim of the presented study was to determine the presence of RAE among the top orienteering male and female athletes (n = 469) in the categories of pupils, juniors, and youth (age categories U12-U20) in the Czech Republic. The data was obtained from the Orienteering Information System (ORIS). Based on the birthdate, the runners were categorized into quartiles (Qi) and semesters (Si). The resulting data was compared with the expected data for the individual parts of the year. The analysis was conducted using the Chi-square test (χ2 test) in the Goodness-of-Fit version. The results showed that in the entire sample, more runners were born in the second half of the year. Similarly, this was the case in the individual categories, except for the age category U16 and U18. In the category U16, more athletes were born in the first half of the year, which was the only exception, and in the category U18, the distribution of birthdates within the semesters was balanced. However, in the entire sample and in none of the individual categories, the statistical significance of the results was confirmed (p > 0.05). The achieved results may be influenced by several factors, with one of these factors likely being the fact that it is a non-Olympic sport and is still relatively marginal in the Czech Republic. For this reason, it appears that the influences that support RAE are not so significant as to significantly affect the presence of this phenomenon.
The Relative Age Effect (RAE) has been the subject of many studies, but few have focused on professional athletes in individual sports. The aim of this study was to verify the existence of the RAE among elite senior female tennis players (top 100 players) in the WTA Rankings (n = 1000) in the years 2007-2016. The analysis was performed among top 100, resp. top 10 female tennis players, among players in 4 age subgroups and among left-handed (LH) and right-handed (RH) players. The existence of the RAE was assessed with the use of chi-square test (goodness of fit). More than half of top 100 players were born in first semester: both in individual years (53.0-63.0%) and in the whole observed period (58.4%). Significant RAE (ES medium) was observed in top 100 female players only in 2012 and 2016; significant RAE (ES small) was detected in the period of 2007-2016. Among the top 10 players, significant RAE (ES medium) was demonstrated during the whole period. No significant RAE (ES medium) was detected in the 17-18y subgroups, significant in 19-24y and 25-30y (ES small) as well as in 31-36y (ES medium). Although significant RAE was observed in the subgroups of LH and RH female players, ES was large only in the LH. The results contribute to the expansion of the knowledge about the reduction of the RAE existence in adulthood among coaches, athletes and tennis officials.
- MeSH
- dospělí MeSH
- lidé MeSH
- porod MeSH
- rozdělení chí kvadrát MeSH
- sportovci MeSH
- těhotenství MeSH
- tenis * MeSH
- zákroky plastické chirurgie * MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PURPOSE The issue of the Relative Age Effect (RAE) has been studied in the theory of sports for more than 30 years. Most studies concentrate on team sports, while the area of some individual sports like swimming can be considered still underexplored. METHODS The aim of our study was to verify the RAE in young elite swimmers (n = 198) who participated in Czech Republic U14 Championship (1) in male and female samples (2) according to swimming disciplines and distances (3) and performance (times in individual disciplines) between individual quartiles / semesters of birth. The analysis was performed with the use of adequate statistical (chi-square test, Kruskal-Wallis H test, Mann-Whitney U test) and effect size (effect size w index, eta-square test, effect size r index) tests. RESULTS The results showed a different intensity of RAE sex-differences (male: w = 0.033; female: w = 0.006). In the division by the swimming disciplines and swimming distances, statistically significant values with large effect size were found in males in 50 m freestyle, 200 m individual medley, 100 m butterfly and 200 m butterfly. However, this did not apply for girls. Analysis of differences in performance showed a significant difference between the dependent variables (sex, distance, discipline) by different independent variables of quartile / semester of birth with large effect size only in cases of male 100 m breaststroke and female 200 m individual medley. CONCLUSIONS The issue of RAE should be circulated among the coaches working with youth, athletes, sports organizations, but also parents of athletes in order to avoid the termination of actively spent time or drop-outs.
Vliv relativního věku (RAE) je fenomén, který silně ovlivňuje sportovní vývoj mládeže. RAE odkazuje na neúměrně vysoké procento sportovců narozených na začátku kalendářního (selekčního) roku. Řada studií, zejména v kolektivních sportech, tuto skutečnost prokázala. V individuálních sportech, jako je například plavání, však stále chybí dostatečný počet studií, což znemožňuje komplexní pochopení problematiky RAE v daném sportu. Cílem naší studie bylo ověřit RAE u mladých elitních plavců (n = 202), kteří se zúčastnili Mistrovství České republiky ve věkové kategorii U12 (1), ve vzorku chlapců a dívek (2) podle plaveckých disciplín a vzdáleností (3) a výkonnosti (časy v jednotlivýchdisciplínách) mezi jednotlivými kvartály /pololetími narození. Analýza byla provedena s využitím adekvátních statistických testů (chí-kvadrát test, Mann-Whitney U test) a výpočtu effect size (ES) (ES index w a ES index r ). Analýza prokázala signifikantní RAE pouze v celém souboru probandů (p = 0,015, w = 0,228, ES = střední), v distribuci podle pohlaví RAE nebyl přítomen. Významný RAE byl v rozdělení podle plaveckých disciplín a plaveckých vzdáleností zjištěn u chlapců v disciplíně prsa /100 m/ (p = 0,001, w = 0,763, ES = velký), prsa /200 m/ (p = 0,004, w = 0,663, ES = velký) a polohový závod /200 m/ (p = 0,007, w = 0,638, ES = velký). U žen byl zjištěn významný RAE v disciplíně volný styl /50 m/ (p < 0,001, w = 0,774, ES = velký) a volný styl /100 m/ (p = 0,001, w = 0,751, ES = velký). Analýza výkonnostních rozdílů mezi výzkumnými kategoriemi (Si) v podobě časů v disciplínách ukázala statisticky významný rozdíl mezi závislými proměnnými (pohlaví, vzdálenost, disciplína) podle různých nezávislých proměnných (Si) pouze v případě dívek: volný styl /100m/ (p = 0,011), polohový závod /100m/ (p = 0,028), motýlek /200m/ (p = 0,015) a polohový závod /400m/ (p = 0,002).
The Relative Age Effect (RAE) is phenomenon that strongly influences youth sport development. The RAE refers to a disproportionately high percentage of athletes born early in the calendar selection year. Number of studies, especially in team sports, has proved this fact. However, there is still a lack of studies in individual sports, such as swimming, which makes it impossible to have a sufficient understanding of the RAE problem in a given sport. The aim of our study was to verify RAE in young elite swimmers (n = 202) who participated in Czech Republic U12 Championships (1) in male and female samples (2) according to swimming disciplines and distances (3) and performance (times in individual disciplines) between individual quartiles /semesters of birth. The analysis was performed with the use of adequate statistical (chi-square test, Mann-Whitney U test) and effect size (effect size index w and effect size index r) tests. The analysis showed a significant RAE only in the whole sample (p = 0.015, w = 0.228, ES = medium), in sex distribution RAE was not present. A significant RAE, in the division according to swimming disciplines and swimming distances, was found in males in the breaststroke /100m/ (p = 0.001, w = 0.763, ES = large), breaststroke /200 m/ (c2(3) = 13.196, p = 0.004, w = 0.663, ES = large) and in the individual medley /200 m/ (c2(3) = 12.214, p = 0.007, w = 0.638, ES = large). In females, there was a significant RAE in freestyle /50m/ (p < 0.001, w = 0.774, ES = large) and freestyle /100m/ (p = 0.001, w = 0.751, ES = large). Analysis of performance differences between research categories (Si) in the form of time in disciplines, showed a statistically significant difference between the dependent variables (sex, distance, discipline) by different independent variables (Si) only in case of female sample: freestyle /100m/ (p = 0.011), individual medley /100m/ (p = 0.028), butterfly /200m/ (p = 0.015) and individual medley /400m/ (p = 0.002).
PURPOSE. Squats are among the basic exercises that have become an integral part of exercise programs. It is commonly used by athletes in many sports. Its potential is shown in the development of strength, power, and overall sports performance. The aim of the study was to verify inconsistent views on deep squats, technical design, and related health risks. METHODS. For the purposes of the review, the terms "squat, knee, biomechanics, deep, patellofemoral, back squat, performance, arthritis, health, injury, risk" were used. RESULTS. It turns out that the technique of performing a deep squat has its strict principles, which must be respected and which have a significant impact on the benefits and risks. From loading, the lower position represents an increase in compressive and shear forces on the patellofemoral joint, however, this is a natural state that is not risky. Health hazards cannot be based on analytical-mathematical models, which are insufficient in this aspect. Extreme long-term exposure carries the risk of permanent consequences in the form of osteoarthritis. For prophylaxis or convalescence, it is possible to use effective aids like sleeves, kinesio taping, bandage or "knee savers". CONCLUSIONS. With optimal technique and sensible exercise selection, there is no greater risk in healthy individuals without degenerative anatomical changes. In order to assess the effects of the squat forces on the ankle, knee, hip, spine, it is necessary to consider the technique and also individual anatomical differences.
Používání slovních instrukcí je běžným nástrojem ke zlepšení motorického učení a výkonu. Aktuální výsledky ukazují, že instrukce, které zaměřují pozornost sportovce externě (zaměřené na pohybový efekt), spíše než interně (zaměřené na pohyby těla sportovce), mají obecně za následek zlepšení motorické výkonnosti. Tato studie poskytuje komplexní přehled stávající literatury, která zkoumala vliv verbálních instrukcí zaměřených na pozornost v plavání. Cílem studie bylo zjistit, jaké pokyny jsou vhodné pro motorické učení a plavecké výkony. Analýza ukázala, že většina dostupných studií se zaměřuje hlavně na samotný výkon, nikoli na motorické učení. Několik studií nicméně potvrdilo hypotézu, že externě zaměřená instrukce má obecně efektivnější účinek - pro závodní plavce i pro nesoutěžní plavce. Na základě výsledků lze také dojít k závěru, že pokyny zaměřené na hnací síly (tj. pohyby paží a nohou) se zdají být pro samotný výkon účinnější než pokyny, které vedou ke správné poloze těla nebo dýchání. Je zřejmé, že ve srovnání s jinými sporty podobného druhu je v oblasti plavání potřeba dalších experimentů zaměřených nejen na výkon, ale také na celý proces motorického učení.
The use of verbal instructions is a common tool to improve motor learning and performance. Current results show, that providing instructions that focus an athlete's attention externally (directed at the movement effect), rather than internally (directed at the athlete's body movements), generally result in enhanced motor skill performance. This study provides a comprehensive review of the existing literature which examined the influence of verbal attentional focusing instructions in swimming. The aim of the study was to find out what kind of instructions are suitable for motor learning and swimming performance. Analysis has shown that most of the available studies are focused mainly on performance itself, not motor learning. Nevertheless, several studies have confirmed the hypothesis that externally directed instruction appears to have a more effective effect in general - for competitive swimmers and also for non-competitive swimmers. Based on the results, it can also be concluded that instructions directed at driving forces (i.e. arm and leg movements) appear to have a more effective effect for performance, than instructions that lead to the correct body position or breathing. It is obvious that in comparison with other sports of a similar nature, in the field of swimming there is a need for further experiments focusing not only on performance but also on the whole process of motor learning.
- Klíčová slova
- attentional focus, external attentional focus, internal attentional focus, swimming, motor learning, záměrná pozornost, vnější záměrná pozornost, vnitřní záměrná pozornost, plavání, motorické učení,
- MeSH
- lidé MeSH
- plavání * výchova MeSH
- pozornost MeSH
- učení MeSH
- vyučování MeSH
- Check Tag
- lidé MeSH
The issue of the Relative Age Effect (RAE) has been long researched, discussed and published both in the academic and coaching community and the number of studies on it in various sports has significantly grown in recent years. The aim of this study was to verify the existence of RAE among Czech male (n = 6552) and female (n = 4131) junior tennis players and to identify possible differences in birthdate effect between male and female players. The research was carried out in players registered in the years 2007–2016 in the U14 age category in Czech Tennis Association (CTA) database; the athletes were divided into three subgroups (‘Ranked’, ‘Top 100’, ‘Top 10’). Research data were analysed by the methods of descriptive and inferential statistics: relative and absolute frequency, chi-square goodness of fit test () and chi-square test of independence () with the use of effect size (ES index w). A declining tendency of frequencies from Q1 to Q4 between male and female junior players was proven in all three subgroups.In the whole period of 2007–2016, a significant and strong RAE was demonstrated only in the ‘Top 10’ male subgroup (RAE was significant and ES was small or trivial in the other two subgroups). Among the female players, RAE was significant in all three subgroups (ES was small or trivial). Gender differences in RAE in favour of male players were significant in ‘Top 100’ and ‘Ranked’ (ES was small or trivial in all three subgroups). In the short and long term, RAE can have significant implications for the sport development of athletes; both coaches and the professional public can therefore be recommended to pay attention to this issue. The impact of RAE in sport, i.e. the uneven distribution of athletes’ birthdates, is more pronounced especially among junior athletes and often significantly affects their sports development and career.
The relative age effect (RAE) theory is based on the premise that athletes born in the first months of the calendar year have a significant probability of a higher level of physiological, morphological and psychological abilities compared to later-born athletes. The aim of our study was to verify the influence of the RAE on adult ice hockey players, specifically Ice Hockey World Championships' (IHWC) participants in the years 2015-2017 (n = 1,200). Based on the chi-squared (χ2) analysis, the influence of the RAE during the 2015-2017 period could not be rejected for all observed players (χ2 = 54.6, p < 0.01, w = 0.21) or for all the players for particular years (2015, 2016, and 2017; p < 0.01). During the monitored period (2015-2017), the RAE could not be rejected for any player's position (forward, defender, or goaltender). Based on the effect size analysis (Cohen's w), the strongest RAE was observed among goaltenders (w = 0.31), then forwards (w = 0.24) and finally defenders (w = 0.15). The assessment of player's positions in particular years showed statistical significance for goaltenders only in 2015 (χ2 = 11.3, p < 0.05). With regard to forwards, significance was confirmed for 2015 (χ2 = 8.5, p < 0.05), 2016 (χ2 = 15.2, p < 0.01) and 2017 (χ2 = 14.3, p < 0.01). Therefore, the presence of the RAE could not be rejected for all these cases. The results of the research show that members of national teams in the years 2015-2017 were players who were chronologically older, which is consistent with the results of other authors addressing the RAE.
- Publikační typ
- časopisecké články MeSH
Teorie senzitivních období je známým konceptem, který je nedílnou součástí výuky na akademické půdě. Jeho přesah je patrný v praxi sportovního tréninku dětí a mládeže nebo ve školní tělesné výchově. Pojetí rozvoje silových schopností úzce navazuje na věkové vyhranění spojeného s předpokládanou vyšší resp., nižší citlivostí. Článek se zabývá kritickým zhodnocením senzitivního období prepubescentů s ohledem na rozvoj silových schopností. Dále popisuje relevantní studie zabývající se účinky silových programů u této věkové skupiny. Zdá se, že ještě před nástupem puberty je organismus velmi dobře připraven pro adaptaci na silové zatížení. Na základě uvedených informací by bylo vhodné revidovat přístup k rozvoji silových schopností dětí a mládeže.
Window of oportunity theory is a well-known concept that is an integral part of academic teaching. Its overlap is evident in the practice of sports training for children and youth or in school physical education. The concept of the development of strength abilities is closely related to the age demarcation associated with the assumed higher or lower sensitivity. The article deals with the critical evaluation of the window of oportunity of prepubescents with regard to the development of strength abilities. It also describes relevant studies on the effects of strength programs in this age group. It seems that before the onset of puberty, the body is well prepared for adaptation to the strength load. On the basis of this information, it would be appropriate to revise the approach to developing the strengths of children and youth.
