Search

One of the most convincing studies about the importance of the cutoff date in relative age effects was when Helsen et al. (2000) showed that a shift in the date directly resulted in a change of birth month distributions in soccer. Over the past four decades, the role of the birth year has also been associated with relative age effects (as reflected in constant year effects). In this investigation, two studies attempted to replicate the shift of birth year distributions caused by a change in birth years in international female handball. In Study 1, the results from the female handball world championship 2017 showed a significant within‐year effect overall and a constant year effect for players born 1988 and after. A second study was conducted with female players from world championships in 2009, 2011, 2013, and 2015. Results demonstrated small effect sizes for most tests. However, there was an unexpected trend toward a constant year effect shift at the age of 28 years. Several hypotheses are presented as an explanation for this trend. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Psicología del Deporte is the property of Cuadernos de Psicologia del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aimed to analysis the birth date distributions of the champion players between the years 1930-2022 to determine whether the FIFA World Cup champion national team football players between the years 1930-2022 were affected by the "Relative Age Effect" phenomenon. The universe of the research consisted of the national teams that were champions in the 1930-2022 FIFA World Cup Finals. The samples consisted of the football player group of the national teams that won the championship. The model of the research was determined as "Basic Qualitative Research". The data collection technique in the research was determined as "Document Analysis". The data analysis was made according to the Miles & Huberman model, which is a descriptive analysis form. In the study, the information of the athletes was detailed by looking at the squad structure for the FIFA World Cup champion national team football players between the years 1930-2022. In the highest level of professional football, it has been seen that the champion national team football players are numerically close to each other in terms of "relative age effect". As a result, it has been observed that the relative age effect in senior football decreases with increasing age. It was shown that the relative age effect in professional elite national teams changed negatively due to the high number of football players born in the second half of the year. In this case, it was not a negative situation for football players who transition to professionalism and reach the elite level, being born in the last months of the year. Looking at the intercontinental comparison, even considering the different football culture and structure, it has been revealed that late-born athletes have caught up with their peers at a professional level and even left them behind. [ABSTRACT FROM AUTHOR]

Copyright of Spor Bilimleri Dergisi is the property of Spor Bilimleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Our aim in this study was to analyze: (i) the presence of the relative age effect (RAE) on the Brazilian elite female futsal athletes according to their team's final position in the National Championship, and (ii) the relationship between the presence of the RAE and the athletes' tactical individual performance. Participants were 77 female Brazilian elite futsal athletes that competed in the 2021 National Championship. Data included their dates of birth aggrupation by quartiles (Q1-Q4), their team's final position in the National Championship, and their tactical individual performance indicators (time played, goals scored, assists, steals, shots on goal, unbalanced passes, and challenges won in 1vs1). Analyses of the overall sample indicated that RAE was not prevalent in this context since the observed birthdate distribution was not different from the expected one (p=.796). When the final placement in the championship was considered, the birthdate distributions were also not different from the expected for both the top-ranked (p=.572) and low-ranked (p=.679) team athletes. Regarding athletes' tactical individual performance, no differences were found between the athletes with early and late birthdates for any of the variables analysed (p>.05). Our results suggest that RAE has no impact on this specific sport context, which should be interpreted as a positive factor since female futsal athletes seem to have the same chance of achieving the elite level in Brazil, regardless of their birthdates. [ABSTRACT FROM AUTHOR]

The relative age effect is considered to be the main cause of the uneven distribution of birthdates in sports teams, particularly in football. The aim of this paper is to examine the presence of the relative age effect in the leagues of the former Yugoslav republics and the differences in birthdates distribution between the leagues. To test hypotheses, we used publicly available information obtained from official websites, which regarded players who played in the analyzed leagues during the 2020/2021 season. The absolute results indicate that in five of the six observed leagues, the greatest number of players were born in the first quartal of the year. A more detailed observation of each league individually found a significant relative age effect among players who play in the Serbian, Croatian and Slovenian leagues, but not in Northern Macedonia, Montenegro, and Bosnia, and Herzegovina. Also, the results show that the quarterly distribution of analyzed leagues does not differ significantly. The results of this paper should serve the purpose of raising awareness about the presence of the relative age effect in regional football. All this should affect the creation of an environment in which all football players would have an equal chance for development and progress, reduce the chances of overlooking potential talents and ultimately raise the quality of football in the region. [ABSTRACT FROM AUTHOR]

The objectives of this study were to analyze calf performance traits and sex ratio frequencies in reciprocal Bos indicus–Bos taurus F2 Nellore–Angus calves (n = 539). The F2 calves were produced using reciprocal Angus-sired (AN) and Nellore-sired (NA) F1 sires and F1 dams, resulting in four F2 cross types. Calf weight traits were analyzed using mixed models. Deviations from 50% calf sex ratios were tested against expected binomial thresholds. Dam type influenced Julian birth date (p < 0.05) with calves from AN cows born 5 to 6 days earlier than calves from NA cows. Sire type and dam type affected birth weight (p < 0.05) with calves from NA parents approximately 2.5 kg heavier than those from AN parents; weaning weight did not differ for parent F1 type. However, an interaction between sire and dam types affected weaning weight (p = 0.038) where AN x AN calves were 5 to 8 kg lighter than other crosses. Sire type influenced calf sex distribution at birth (p = 0.036) and at weaning (p = 0.026) with NA sires producing over 66% male calves. These results suggest birth weight reciprocal differences due to parental line of descent typically observed among F1 Bos indicus–Bos taurus crosses can persist in subsequent generations. [ABSTRACT FROM AUTHOR]

Grade retention has been the focus of the education debate in Spain for decades. On average, more than 30% of students have repeated at least one grade before they finish (or dropout from) their compulsory studies. The present research provides new evidence on this issue by investigating the influence of Spain's school entry age upon students' grade retention. Using data from 15-year-old students who participated in the PISA 2006, 2009, 2012 and 2015 assessments, we implement a regression discontinuity analysis. Our key finding is that students who were born late in the year (younger students) are more likely to repeat a grade. Yet, once they reach secondary education, the disadvantage they suffer due to their younger school starting age seems to disappear. Hence, the key reason why younger students have lower PISA scores than older students in Spain is due to their increased likelihood of repeating a grade, rather than being due to their relative age per se. To avoid these artificial disadvantages of younger students and unfair retention, we suggest that policymakers inform families about this school entry issue and also make the school entry law more flexible. This would facilitate parents of younger children to choose whether to delay their children's school enrolment or not. [ABSTRACT FROM AUTHOR]

The issue of Relative Age Effect (RAE) focuses on the causes and consequences of the failure to respect development patterns of individuals in relation to their success, especially in sports. This study aims to determine whether the influence of the RAE can be proven in the Czech youth ice hockey league (U15) (n=744). A Chi-Square test (χ2) has shown that the influence in the whole investigated group cannot be rejected (χ2=25.34, p

A child's relative age within their school year ('relative age') is associated with educational attainment and mental health. However, hypothesis driven studies often re-examine the same outcomes and exposure, potentially leading to confirmation and reporting biases, and missing unknown effects. Hypothesis-free outcome-wide analyses can potentially overcome these limitations. We conducted a hypothesis-free investigation of the effects of relative age within school year. We used an instrumental variable (IV)-pheWAS in the UK Biobank (participants aged 40-69 years at baseline), using the PHESANT software package. We created two IVs for relative age: being born in September vs. August (n=64 075) and week of birth (n=383 309). Outcomes passing the Bonferroni-corrected P value threshold for either instrument were plotted to identify a discontinuity at the school year transition. 13 traits associated with at least one of the instruments showed a discontinuity. Previously identified effects included those with a younger relative age being less likely to have educational qualifications and more likely to have started smoking at a younger age. We detected a few associations not explored by previous studies. For example, those with younger relative age had better lung function as adults. Hypothesis-free approaches could help address confirmation and reporting biases in epidemiology., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health.)

In 2019, numerous championships of youth categories soccer national teams were held. In the present study, we analyzed the existence of the Relative Age Effect (RAE) in four major male championships that, due to their importance and participating teams, most likely brought together the great bulk of the players who will dominate professional soccer in the next decade. Participants were professional and amateur youth male soccer players who participated in the last international championships: UEFA European Under-21 Championship (2017–2019); UEFA European Under-19 Championship (2019); South American Youth Football Championship (also known as Conmebol U-20) (2019); and FIFA U-20 World Cup (2019), with 823 players (20.25 ± 0.84 years). In the four championships analyzed, the existence of RAE was found for all players (p < 0.001). Analyzing the players when considering their position on the pitch and their championship, RAE was found, statistically significant, in 10 of the 16 classifications. New generations of elite soccer players arrive with a clear bias in the selection of talent; an unfair bias, based on unequal opportunities in early categories, which should be reviewed by sports authorities. [ABSTRACT FROM AUTHOR]

This paper aims to clarify the date of birth of the Spanish Golden Age poet, Bernardo de Balbuena, based on the interpretation of a passage from his epic poem El Bernardo in which a remarkable element of his natal astral chart is presented: his birth under the great conjunction of 1563. After compiling all the available documentary information from the period, it presents a panorama on the evolution of the doctrine of the great conjunctions and evaluates the poet’s strategy of self-dignification through signaling of his birth under this astrological phenomenon and his double relationship, both astral and onomastic, with his poetic hero. [ABSTRACT FROM AUTHOR]

It is approximately 35 years since the publication of the first relative age effect paper in sport and despite the volume of empirical studies, book chapters, conference presentations, and column inches dedicated to this topic we appear to be no further on in eliminating or attenuating this discriminatory practice. This commentary argues that the ongoing use of univariate methods, focusing on primary or secondary analyses of birth-date data, unearthed from previously un-examined contexts is not conducive to stimulating discussion or providing empirical solutions to relative age effects. This paper concludes by suggesting a departure from the traditionally narrow view of relative age inquiry and instead consider the role of transdisciplinary research. [ABSTRACT FROM AUTHOR]

The relative age effect (RAE) is a phenomenon present in team sports, but it does not influence each gender to the same extent. This study aimed to examine the RAE and its relation to performance in international women's handball competitions (2017/18 World Championships). The sample was composed of 1,096 female players distributed into three categories: youth or under 18 (n = 369); junior or under 20 (n = 328) and senior (n = 399). The teams were divided into four groups based on their final position (medalist, quarter-finalist, eight-finalist and bottom-eight teams). The birthdate distribution (trimesters and semesters) was analysed according to the competition category and the playing position. Differences between the expected and observed birthdate distribution were checked using the chi-square statistical test followed by the calculation of the odds ratio. The results revealed, by trimester, the presence of the RAE in the youth (x2(7) = 87.22; p < 0.001) and junior (x2 (7) = 33.12; p < 0.001) categories, with no impact on senior (p > 0.05). The effect size was relatively strong in the youth category (Vc = 0.48). By semester, the prevalence of the RAE was also found in the senior category (p < 0.05). According to the playing position, the RAE was especially detected in 'goalkeeper' (p < 0.01) and 'centre-back' (p < 0.05) positions, both in U-18 and U-20 categories. Surprisingly, this effect also appeared in the 'back' players in the senior category (p < 0.05). A prevalence of the RAE was identified in teams with a higher final position, but interestingly had a greater impact in the quarter-finalist teams (p < 0.001) than in the medalist teams (p < 0.01). The findings demonstrated that the RAE tends to decrease as the chronological age of players increases, demonstrating a strong presence according to collective performance in international women's handball. [ABSTRACT FROM AUTHOR]

Despite the high global invasion profile of Gambusia holbrooki, there is limited knowledge of its population dynamics, especially biological parameters for fine-scale delineation of recruitment events that can provide a basis for controlling this short-lived invasive species. Key to this is daily ageing of otoliths, and in this study 193 (~ 50%) of 394 wild fish sampled from an invaded wetland were successfully aged. Increment counts of growth rings in otoliths from aquaria-reared G. holbrooki did not correspond 1:1 to their known ages but were significantly correlated (P < 0.05, R2 = 0.92), suggesting the use of linear relationships could nevertheless be used to estimate the age of wild-caught fish. Mean daily growth rate estimated for spring-summer cohorts (0.28 mm/day) was much greater than that of winter cohorts (0.12 mm/day). A natural mortality rate of 0.01 day− 1 for females was estimated by catch-curve analysis via length to age conversion based on the growth relationship. Birth rate closely correlated with changes in water temperature with a peak reproduction in January (Austral summer) at the study site. This study, for the first time, used daily age estimates of G. holbrooki to quantitatively examine population dynamics, which can be used to investigate invasive dynamics and choice of pest control strategies, including their scheduling and assessment. [ABSTRACT FROM AUTHOR]

Global positioning system (GPS) technology is increasingly used to study animal behavior. However, some animals exhibit behaviors that may result in the failure to acquire a GPS position, such as for species with underground denning behavior. This creates a challenge for researchers to identify the timing of important life-history events such as birth. Here, we tested if information gaps arising from unsuccessful GPS positions, in connection with intrinsic and extrinsic factors, can identify parturition events in an underground denning species, the red fox. Using data from 30 GPS collared female red foxes during the approximate parturition period of 1 March–31 May, we calculated the proportion of successful GPS positions per day. We then compared the patterns of successful GPS positions for females of known reproductive status to those known not to have reproduced and a subset of females for which reproductive status was unknown. Females confirmed to have pups (n = 11) and two females of unknown reproductive status showed a significant difference in the proportion of successful GPS positions compared to females without pups, illustrating that parturition and denning activity could be identified from GPS data. None of the 12 subadult females were identified as denning. Parturition date, identified as the day with the lowest GPS fix rate within the five-day period with the lowest proportion of successful GPS positions, ranged from 20 March–14 May, with a mean parturition date of 12 April. We, therefore, conclude that important biological information, such as reproductive status and parturition dates, can be identified from patterns of missing GPS positions for some underground denning species. [ABSTRACT FROM AUTHOR]

The education laws of each country establish starting cutoff dates for compulsory education which could, potentially, affect students' academic achievement. Specifically, they could be detrimental for those students whose birthday is just before the school entry cutoff, as they will be the youngest in their classroom, while it could boost the academic performance of those whose birthday is just after (the eldest ones). The present research paper analyses this issue in respect to students' academic achievement using census and longitudinal data for the most populated region of Spain (Andalusia) with a regression discontinuity methodology. Our results show that those students who are the youngest in the classroom due to this school entry cutoff present lower academic achievement compared to the eldest students, an effect which is reduced while students advance in their education. This motivates policy recommendations aimed at checking students' cognitive skills prior to their access to compulsory education and at letting parents choose whether or not to delay their children's access to school in case they are not yet ready. [ABSTRACT FROM AUTHOR]

This research examines how the implicit egotism resulting from consumers’ positive self-associations affects their evaluations of product prices. The effects can occur when the product’s price and the consumer share either name-letters (name-letter/price effect) or birthday-numbers (birthday-number/price effect).Through a series of studies, the authors demonstrate that the positive affect linked to name-letters and birthday-numbers transfers directly to consumers’ price predilections and ultimately affects their purchase intentions. More specifically, consumers like prices (e.g., “fifty-five dollars”) that contain digits beginning with the same first letter (e.g., “F”) as their own name (e.g., “Fred,” “Mr. Frank”) more than prices that do not. Similarly, prices that contain cents digits (e.g., $49.15) that correspond to a consumer’s date of birth (e.g., April 15) also enhance pricing liking and purchase intentions. Across groups of consumers, the authors’ findings demonstrate that implicit egotism effects can result in greater purchase intentions for a higher-priced product compared with a lower-priced product. [ABSTRACT FROM AUTHOR]

Despite various solutions proposed to solve the relative age effect (RAE), it is still a major problem confounding talent identification and selection processes. In the first phase, we sampled 302 under 7–21 academy soccer players from two Belgian professional soccer clubs to explore the potential of a new approach to solve the inequalities resulting from relative age- and maturity-related bias. This approach allocates players into four discrete quartile groups based on the midway point of their chronological and estimated developmental (ED) birth dates (calculated using the growth curves for stature of Belgian youth). With the use of chi square analyses, a RAE was found (p < 0.01) for the overall sample (Q1 = 41.4% vs. Q4 = 14.9%) that completely disappeared after reallocation (Q1 = 26.5%; Q2 = 21.9%; Q3 = 27.5%; Q4 = 24.2%). According to the new allocation method, the stature difference was reduced, on average, by 11.6 cm (from 24.0 ± 9.9 to 12.4 ± 3.4 cm, d = 1.57). Body mass difference between the two methods was 1.9 kg (20.1 ± 11.3–18.2 ± 13.1 kg, respectively, d = 0.15). The new method created a maximum chronological age difference of 1.9 vs. 0.8 years for the current method. With the use of this method, 47% of the players would be reallocated. Twenty-three percent would be moved up one age category, and 21% would be moved down. In the second phase, we also examined 80 UK academy soccer players to explore if reallocating players reduces the within-playing group variation of somatic and physical fitness characteristics. The percentage coefficient of variation (%CV) was reduced (0.2–10.1%) in 15 out of 20 metrics across U11–U16 age categories, with the U13 age category demonstrating the largest reductions (0.9–10.1%) in CV. The U12 and U13 age categories and associated reallocation groupings showed trivial to small (ES = 0.0–0.5) between-method differences and trivial to moderate (ES = 0.0–1.1) differences within the U14–U16 age categories. A reduction in RAE may lead to fewer dropouts and thus a larger player pool, which benefits, in turn, talent identification, selection, and development.

One of the environmental variables associated with early talent development and the achievement of a high level of proficiency in sport is the relative age effect (RAE). The purpose of our study was threefold: (a) to calculate the RAE in young Israeli athletes (ages 14–18 years); (b) to examine how the athletes perceived this effect, if the effect indeed exists; and (c) to compare the RAE findings of this study with those of two previous studies on elite male (Lidor et al., 2010) and female (Lidor et al., 2014) Israeli ballplayers. Participants in the current study were 1,397 athletes (390 females and 1,007 males) who competed in five individual (gymnastics, judo, swimming, tennis, and track and field) and five team (basketball, soccer, team handball, volleyball, and water polo) sports. Data on the RAE, as well as on a number of aspects associated with this effect as perceived by the athletes, were collected via two closed questions. Data analyses showed that the RAE was found to be significant among the male athletes in four sports—swimming, basketball, soccer, and team handball; those who were born early in the year had a higher representation in these sport programs. However, this effect was not found to be significant in the female athletes. Most of the female and male athletes did not think that their birth date influenced their athletic success. However, a large portion of those who were born in the first quarter of the year (Q1) and the second quarter of the year (Q2) among the male athletes felt that they exhibited stronger abilities in the sports program compared to their peers who were born in the third and fourth quarters of the year (Q3 and Q4, respectively). The data of the current study provide additional support for the use of an “open door” approach to accepting children to sport programs by policymakers and coaches in Israel.

The present study aimed to investigate the influence of months of birth on anthropometry, body composition, biological maturation, and motor performance in young Brazilian soccer players. Young Brazilian soccer players from the Under-13 (n = 50; 13.6 ± 0.3 years), Under-15 (n = 50; 15.5 ± 0.4 years), and Under-17 categories (n = 46; 17.7 ± 0.3 years) took part in this study. Athletes were divided according to chronological age, 1st tertile (January to April); 2nd tertile (May to August); and 3rd tertile (September to December). Anthropometry, body composition, biological maturation, and motor performance variables were evaluated for all participants. There were no differences between the U-13, U-15, and U-17 categories regarding birth tertiles (p > 0.05). Differences between the ages and birth tertiles were observed for the stature, body mass, and lean body mass (p < 0.05). Moreover, differences were found in maturational status between the ages and birth tertiles (p < 0.05). In general, U-13 players showed lower values compared to U-15 and U-17 players in tests of motor performance. In addition, there was a difference in motor performance between the birth tertiles only for RSA variables. The months of birth influenced the stature, body mass, lean body mass, and repeated sprint ability in the U-13 and U-15 categories. Thus, care should be taken during the process of talent selection, as many young players could be underestimated due to their date of birth. [ABSTRACT FROM AUTHOR]

Background: Increasing worldwide rates of cesarean section are of global concern. In recent years, cesarean births upon maternal request have become a hotly debated issue. Hence, this study aimed to explore maternal reasons for cesarean preference without medical indications.Methods: A descriptive qualitative study was conducted, using in-depth interviews with 27 pregnant women who preferred cesarean birth, attending antenatal care in Songklanagarind Hospital from September 2018 to June 2019. Data were analyzed using content analysis.Results: Maternal reasons for cesarean preference were classified into six main categories: fear of childbirth, safety concerns related to health risk perceptions, negative previous birth experiences, positive attitudes toward cesarean birth, access to biased information and superstitious beliefs in auspicious birth dates. Most women had more than one reason for opting cesarean birth.Conclusion: Several reasons for cesarean birth preference have been elucidated. One striking reason was superstitious beliefs in auspicious birth dates, which are challengable for obstetricians to deal with. Obstetricians should explore the exact reasons why women request cesarean birth in order to prevent or diminish unnecessary cesarean births. [ABSTRACT FROM AUTHOR]

Emperor Constantine V was born in the summer of 718, however our only two texts that provide an approximate date of his birth diverge on the matter; mid-July according to Patriarch Nikephoros' Breviarium, and early September according to Theophanes' Chronographia. This paper first analyses the place of Constantine V's birth in the two texts and argues that Theophanes moved the birth to attach it to the baptism episode, which was a separate event, effectively distorting the date of birth. The article also proposes that Theophanes had both practical and ideological reasons to do so and suggests that with the current state of the sources, evidence from the Breviarium is more likely to be closer to the actual date of birth of the infamous iconoclast emperor. Considering that the birth of an imperial heir had a legitimizing value, demonstrating the divine favour shown to the current ruler, and the importance of victory in 718, the last section of this paper further analyses whether the date--just before the retreat of the Arab army besieging Constantinople for about a year--may have played a role in Isaurian propaganda or in the memory of Constantine V as a triumphant ruler. [ABSTRACT FROM AUTHOR]

Summary: Cortical pyramidal cells are generated locally, from pre-programmed progenitors, to form functionally distinct areas. By contrast, striatal projection neurons (SPNs) are generated remotely from a common source, undergo migration to form mosaics of striosomes and matrix, and become incorporated into functionally distinct sectors. Striatal circuits might thus have a unique logic of developmental organization, distinct from those of the neocortex. We explore this possibility in mice by mapping one set of SPNs, those in striosomes, with striatonigral projections to the dopamine-containing substantia nigra pars compacta (SNpc). Same-age SPNs exhibit topographic striatonigral projections, according to their resident sector. However, the different birth dates of resident SPNs within a given sector specify the destination of their axons within the SNpc. These findings highlight a logic intercalating birth date-dependent and birth date-independent factors in determining the trajectories of SPN axons and organizing specialized units of striatonigral circuitry that could influence behavioral expression and vulnerabilities to disease.

Background: Type I diabetes mellitus (T1DM) with growing frequency which is considered as a world health threatening problem is an autoimmune disease with insulinupenia. Considering the relationship between the incidence of T1DM and environmental factors, the aim of this study was to assess seasonal incidence of T1DM and its association with birth season. Methods: This cross-sectional study was conducted on 112 diabetic patients (66 males, 46 females) less than 18 years, referred to Pediatric Endocrine Clinic (Amirkola Children's Hospital) during 2011-2017. All the needed information was extracted from the patient's files and asking questions of their parents. Data were collected in a checklist. Comparison between different seasons and age groups was done by Pearson's chi-square test. Data were analyzed using SPSS 19 and p£0.05 was considered significant level. Results: The mean age of the patients during diagnosis of T1DM was 7.34±3.70 years. The incidence of T1DM was significantly increased in the cold seasons (especially winter) (P

Though the existence of Relative Age Effects (RAEs) has been documented through a multitude of studies spanning various sports and levels of play, application of solutions related to RAEs has been limited. In this review, the strengths and weaknesses of various proposed solutions to RAEs in youth sport are considered. Our objective was to identify, collate, and disseminate a comprehensive list of solutions related to the prevalence of RAEs in youth sport. English language, peer-reviewed articles were searched using the SPORTDiscuss database. Keywords 'relative age', 'relative age effect*', and sport* were used to locate research articles. The inclusion criteria were the following: (1) publication date between January 1980 and December 2018; (2) solutions were suggested related to RAEs. Sixty-three peer-reviewed publications contained proposed solutions to RAEs. Many solutions have been proposed to address RAEs in sport. Most are theoretical and there has been no attempt to implement them. Future research should test possible proposed solutions to RAEs in sport. However, implementing these solutions has the potential to both positively and negatively affect career and life outcomes for those athletes involved. Therefore, it is important to be cautious in how these possible solutions are tested. [ABSTRACT FROM AUTHOR]

The issue of Relative Age Effect (RAE) focuses on the causes and consequences of the failure to respect development patterns of individuals in relation to their success, especially in sports. This study aims to determine whether the influence of the RAE can be proven in the Czech youth ice hockey league (U15) (n=744). A Chi-Square test (X²) has shown that the influence in the whole investigated group cannot be rejected (X²=25.34, p<0.01, w=0.11). The RAE can be rejected in the group of players (n=78) from the three best teams of the competition (X²=3.09, p=0.38, w=0.11); the influence of the RAE can also be rejected in players (n=75) from the three worst teams (X²=0.53, p=0.91, w=0.05). The assessment of RAE on playing positions has shown that the RAE can be rejected (X²=7.31, p=0.06, w=0.22) in the most productive forwards (n=50) as well as in the least productive forwards (n=50) (X²=0.48, p=0.92, w=0.06). The RAE is rejected in the group of the most productive defensemen (n=50) (X²=1.71, p=0.11, w=0.11), and in the group of the least productive defensemen (n=50) (X²=4.15, p=0.25, w=0.17). The RAE cannot be rejected (X²=8.88, p=0.03, w=0.35) in the group of best goaltenders (n=24); the RAE is rejected in the group of the worst goaltenders (n=24) (X²=1.5, p=0.68, w=0.14). Although the results have proven that the RAE cannot be rejected in the entire research group, there is no evidence of its influence (with the exception of the best goaltenders) in individual playing positions. [ABSTRACT FROM AUTHOR]

Thermal conditions during pregnancy affect the length of gestation and phenotype of offspring in viviparous lizards. However, past studies have typically exposed females to basking treatments throughout pregnancy, meaning that effects specific to late pregnancy (including cues for parturition) or to night temperatures are poorly understood. We examined effects of thermal treatments during late-embryonic development on Woodworthia 'Otago/Southland', a viviparous gecko with an unusual capacity to reproduce annually or biennially. Among females from a cool-climate, biennially reproducing population, elevated levels of basking opportunity and night temperature during late summer together increased the proportion of births occurring before winter in the laboratory. Offspring born before winter also had higher mass and body condition than those born after winter. Regardless of the season, the daytime body temperature of females declined shortly before parturition (putatively assisting survival of fully developed embryos in utero), then increased immediately after parturition to match that of neonates. Overall, the combined effects of warmer days and nights could help to explain geographical variation in birth season for this species. Furthermore, climate change might shift the modal birth season at cool sites from spring to the preceding autumn, with loss of offspring mass in utero over warm winters also potentially favouring a shift in birth season over time. [ABSTRACT FROM AUTHOR]

The relative age effect (RAE), within the sporting scope, refers to the possible advantages of participation and performance of athletes born in the first months of the year of selection in relation to others within the same age category. The aim of the present study was to investigate the RAE in girls' volleyball players participating in the U-18 World Championship, analysing the differences between the medal teams and other teams in the tournament, and considering this phenomenon in relation to the continents. Data collection was obtained from the website of the International Volleyball Federation with a sample made of 1654 youth players in the last six world championships (2007, 2009, 2011, 2013, 2015 and 2017). A greater representation of athletes born in the first months of the year of all the world championships was observed. In the comparison among the continents, it was observed that in Africa, there was a more equal distribution of quartiles compared to America, Asia and Europe. It should be noted that there was a higher percentage of medalist athletes born at the beginning of the year in comparison to the countries that placed in the last three positions of the championship. Therefore, in U-18 female volleyball, there is an advantage to have the closest birth age at the beginning of the competitive biennium. [ABSTRACT FROM AUTHOR]

Copyright of Dirasat: Educational Sciences is the property of University of Jordan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Aims: To investigate the presence of a relative age effect (RAE) and the influence of birth quarters (BQ), semesters (S) as well as skeletal maturation on anthropometric characteristics and aerobic peak speed (PST-CAR) in youth male soccer players. Methods: One hundred players were recruited to participate in this study. Players were allocated into 4 BQ’s and 2 S. Skeletal maturity status was assessed using the Fels method. Assessments for players included determination of body size and composition and PST-CAR. Results: Overall, more players were born in BQ1 (38 %) and S1 (75%). The likelihood of players born in BQ1 and BQ2 being selected was 3.61 to 4.96 times higher than players in BQ3 and BQ4. Players in BQ4 maturing earlier were biologically older than their peers in BQ1. The players in BQ3 and S2 displayed higher PST-CAR compared with players in BQ2 and S1, respectively. However, players of contrasting skeletal maturity status did not differ in aerobic performance. Conclusion: Our findings indicate that coaches and talent scouts are systematically retaining average and early maturing players born in S1 and excluding late maturing players born in BQ4. However, aerobic performance appeared to be dependent on the relative age, but independent of skeletal maturation during puberty.

Because age-groups in soccer often comprise children born within a 2-year time frame, characteristics that define the profile of a successful player may not be appropriate for the oldest or youngest players of the same age-group. Therefore, this study aimed to determine to what extent performance was influenced by age, maturation, and body size in elite soccer players with barely 1-year age gap. Anthropometry, 15-m sprint test, modified Barrow's agility test, Yo-Yo intermittent recovery test level 1, countermovement jump, and handgrip test were conducted in players aged 12 years and under (n = 82; age, 11.1 ± 0.6 years) and between 12 and 13 years (n = 79; age, 12.8 ± 0.6 years). A total score of performance, chronological age, and age at peak height velocity were calculated. Descriptive statistics, Student's t-tests, and multiple linear regressions were performed. The explained variance in composite score was greater in the older (54%) than in the younger (30%) players. Sum of skinfolds was the primary predictor of 15-m sprint and countermovement jump in the younger group, whereas in the older group, chronological age and body size appeared as predictors of performance (41%). Body size explained the variance in most tests in older players. In the younger group, biological maturity status explained the variance in endurance (35%) and handgrip (59%) tests. In summary, chronological age and sum of skinfolds influenced the most tests; however, predictors differed between age groups. These findings highlight the importance of assessing individual differences in young male soccer players regardless of their similarity in age. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to determine if a Relative Age Effect (RAE) is present in Polish National Football Teams. Material and methods: Birth date distributions of football players from youth Polish National Teams (Under 15 - Under 19) and the senior Polish National Team were compared. The sample (a total of 1801 players) included 909 youth players - U-15 (n=290), U-16 (n=221), U-17 (n=153), U-18 (n=157), and U-19 (n=88) - and 892 professional players who played in at least one official game for the senior Polish National Team. Results: An over-representation of players born in the first quarter of each selection year was identified on all youth teams. Anova Friedman test confirmed that the number of players on youth National Teams is dependent on the month of birth. Anova Kruskala-Wallis test demonstrated a statistically significant difference in the number of players born in January, March, and May. The Relative Age Effect fades with increasing age, and vanishes in full, when players reach the senior Polish National Team level. Conclusions: The bias in selection of youth players may lead to poor talent identification and discrimination in the recruitment of professional football players. [ABSTRACT FROM AUTHOR]

Maternal effects occur when the phenotype of the mother influences that of the young to the detriment of her survival, growth or fitness. The investment of the mother can be affected by maternal body condition and/or experience. Trivers–Willard Hypothesis (TWH) and Local Resource Competition Hypothesis (LRCH) are the main hypotheses used to explain bias in birth sex-ratios in mammals, as well as for sex-biased maternal investment. Both hypotheses suggest that a different amount of investment must be expected according to the sex of the young. However, recent studies suggest that these differences are not in quantity but in the strategies: mechanisms and objectives may differ for each sex. We studied how maternal characteristics (age, body mass, body condition, and dominance status) influence relevant aspects of the birth and early growth of the calf (birth date, birth body mass, body mass at weaning, and body condition at weaning) separately for each sex; and how that investment is mediated by milk production and composition (lactose, fat, and protein). One hundred eighty-eight newborns from 75 captive red deer hinds aged from 2 to 19 years were analyzed. The main differential investment observed was related to birth date: when producing a female, hinds give birth earlier in the season only if they have a good body condition; however, when gestating a male it is the older hinds those which deliver earlier. Subsequently, milk production and composition are correlated with birth body mass in female calves, but to weaning body mass in males. Thus, only hind body mass affects the weaning body mass of female calves, compared with age and hind body mass in males. These results suggest that while TWH fits the maternal investment strategy found for male calves, it is LRCH which correlates with the maternal investment patterns observed for females. [ABSTRACT FROM AUTHOR]