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Understanding the Relative Age Effect (RAE) in female volleyball can provide a deeper insight into potential developmental advantages and selection biases between playing positions and volleyball-related performance characteristics. This study aimed to investigate the occurrence of the RAE in adolescent female volleyball players according to the playing position and the possible differences in anthropometric and performance characteristics between the relative age groups. The study involved 193 young female volleyball players from 12 different regions and 108 sports clubs from all over Greece, with an average age of 14.53 ± 0.31 years, height of 1.67 ± 0.07 m, weight of 57.20 ± 9.10 kg, and body mass index (BMI) of 20.34 ± 2.50. RAE was identified by the birth quarter of each player, categorizing thus the total sample into four sub-groups: Q1 (January-March), Q2 (April-June), Q3 (July-September), and Q4 (October-December). Anthropometrics, upper and lower limb power, agility, flexibility, and trunk strength were also assessed. The distribution of volleyball players differed significantly across birth quarters (34.19% of Q1, 25.9% of Q2, 22.79% of Q3, 17.09% of Q4; χ 2 = 11.788, p = 0.008). Analysis revealed no significant association between birth quarter and playing position (χ 2 = 11.314, p = 0.730). Present study's results indicated no RAE in young female volleyball players regarding their playing position. Also, performance tests did not differ significantly among the RAE groups. Moreover, despite athletes' early specialization based on assigned playing positions, no differences in athletes' position-related performance characteristics were observed. These findings suggest that interventions to mitigate RAE should be considered to ensure equitable development opportunities across all playing positions.

Utilizing comprehensive administrative data from Norway I investigate long-term birth month effects. I demonstrate that the oldest children in class have a substantially higher GPA than their younger peers. The birth month differences are larger for low-SES children. Furthermore, I find that the youngest children in class are lagging significantly behind their older peers on the educational track, and need more time to reach the same level of earnings. [ABSTRACT FROM PUBLISHER]

1. In species with plastic expression of alternative reproductive tactics (ARTs), individuals of the same sex, usually males, can adopt different reproductive tactics depending on factors such as body size. 2. The 'birth date hypothesis' proposes that condition-dependent expression of ARTs may ultimately depend on birth date, because individuals born at different times of the year may achieve different sizes and express different reproductive tactics accordingly. However, this has rarely been tested. 3. Here, we tested this hypothesis in a fish with ARTs, the peacock blenny (Salaria pavo). A long-term (6 years) mark-recapture study demonstrated that ARTs in the peacock blenny were sequential and that males may follow at least two alternative life-history pathways: a nest- holder pathway, in which males express the nest-holder tactic from their first breeding season onwards, and a parasitic pathway, where males reproduce on their first breeding season as sneaker males and subsequently as nest-holders. 4. We have found evidence of a birth date effect on the expression of ARTs in the peacock blenny. Males following the nest-holder pathway are born earlier and are larger at the first breeding season than males following the parasitic pathway, but they have similar growth curves. 5. The mechanisms underlying a birth date effect are far from clear and might be diverse. We have not found support for a mechanism of body size threshold triggering sexual maturation and subsequent ARTs. A mechanism of tactic determination that is strictly based on timing of first maturation is also unlikely. 6. A proxy of lifetime reproductive success shows crossing (body size associated) fitness curves for the two main life-history pathways. [ABSTRACT FROM AUTHOR]

The study investigated the relationships between school achievement and pupil age at entry into first grade and age relative to the class. Data from 101 519 grade 4 pupils were selected from TIMSS 2011 achievement data in mathematics and science, collected from national samples of 25 European countries. Hierarchical regression analysis showed that the effect of class relative age was greater than the effect of grade relative age and it was significantly higher in younger than older classes. Average achievement (especially in science) was better in older classes. [ABSTRACT FROM AUTHOR]