INFLUENCE OF THE RELATIVE AGE EFFECT ON HEIGHT, MOTOR PERFORMANCE AND TECHNICAL ELEMENTS OF OLYMPIC VOLLEYBALL ATHLETES

ABSTRACT Introduction The Relative Age Effect (RAE) refers to the chronological age difference that occurs between athletes of the same age category, which can benefit individuals born in the first two quartiles of the year. This phenomenon is commonly studied in team sports, yet the results are still inconsistent, especially in volleyball. Objective This study analyzed the distribution of the number of births per quartile of Olympic volleyball athletes and whether this would influence anthropometric/motor variables and technical elements. Methods The sample consisted of 116 male athletes who scored during the Rio 2016 Olympics. For data analysis, we identified each athlete’s quartile as well as data on height, attack and defensive (or block) range, and respective scores during the games. The Chi-square test was then used to verify interquartile distribution. To assess the normality of the other variables, we conducted the Kolmogorov-Smirnov test. Once accepted, one-way ANOVA was performed with the Bonferroni post-hoc test to verify significance between quartiles. A significance level of p≤0.05 was adopted. Results There was no significant difference in the distribution of athletes between quartiles (p = 0.74). When comparing the other variables in terms of the athletes’ trimester of birth, we did not observe any significant difference between height (p = 0.79), attack (p=0.59) and defensive range (p=0.07), and in the scores for serving, attacking and blocking between quartiles either. Conclusion The Relative Age Effect was not observed in Olympic volleyball athletes, therefore this phenomenon is not related to the athletes’ performance. This shows that other possible variables may influence the development of these athletes, discarding the relative age phenomenon. Level of Evidence III; Retrospective and Comparative Study.摘要 引言 相对年龄效应（Relative Age Effect，RAE）指同一年龄组别运动员之间存在的实足年龄差异，该效应会使出生于一年中前两个四分位时段的个体获得竞技优势。这一现象在团体项目体育运动中常被研究，但相关研究结论尚未达成共识，在排球项目中尤为如此。 研究目的 本研究分析了奥运排球运动员按出生四分位划分的出生人数分布情况，以及该分布是否会对人体测量学/运动能力变量与技术动作要素产生影响。 研究方法 本研究的样本涵盖2016年里约奥运会男子排球赛事中取得得分记录的116名男性运动员。数据分析环节，首先明确每位运动员的出生四分位时段，同时收集其身高、进攻与防守（拦网）摸高高度，以及赛事期间的相关得分数据。随后采用卡方检验验证四分位组间的分布差异；针对其余变量的正态性，使用柯尔莫哥洛夫-斯米尔诺夫检验（Kolmogorov-Smirnov test）进行评估，若符合正态分布，则采用单因素方差分析（one-way ANOVA）结合邦费罗尼事后检验（Bonferroni post-hoc test）以验证四分位组间的显著性差异，本研究设定显著性水平为p≤0.05。 研究结果 运动员在各四分位的分布未呈现显著差异（p=0.74）。在按出生季度对比其余变量时，身高（p=0.79）、进攻摸高（p=0.59）与防守摸高（p=0.07）均未表现出组间显著差异，各四分位组的发球、进攻与拦网得分同样未发现显著差异。 研究结论 奥运排球运动员群体中未观察到相对年龄效应，因此该现象与运动员的竞技表现无关。这表明存在其他潜在变量影响此类运动员的竞技发展，可排除相对年龄效应的影响。 证据等级：III级；回顾性对比研究。