1Center for Sport and Exercise Science, University of Essex, Colchester, United Kingdom; 2Center for Hip Health and Mobility, University of British Columbia, Vancouver, British Columbia, Canada; and 3Institute of Investigations, Medical School, University of Santander - UDES, Bucaramanga, Santander, Colombia.
J Strength Cond Res. 2013 Dec;27(12):3293-9. doi: 10.1519/JSC.0b013e318291b28d.
The relative age effect (RAE) describes the relationship between an individual's birth month and their level of attainment in sports. There is a clustering of birth dates just after the cutoff used for selection in age-grouped sports, and it is hypothesized that such relatively older sportspeople may enjoy maturational and physical advantages over their younger peers. There is, however, little empirical evidence of any such advantage. This study investigated whether schoolchildren's physical performance differed according to which quarter of the school year they were born in. Mass, stature, body mass index, cardiorespiratory fitness, strength, and power were measured in 10 to 16 year olds (n = 8,550, 53% male). We expressed test performance as age- and sex-specific z-scores based on reference data with age rounded down to the nearest whole year and also as units normalized for body mass. We then compared these values between yearly birth quarters. There were no significant main effects for differences in anthropometric measures in either sex. Girls born in the first quarter of the school year were significantly stronger than those born at other times when handgrip was expressed as a z-score. As z-scores, all measures were significantly higher in boys born in either the first or second yearly quarters. Relative to body mass, cardiorespiratory fitness was higher in boys born in the first quarter and power was higher in those born in the second quarter. The RAE does not appear to significantly affect girls' performance test scores when they are expressed as z-score or relative to body mass. Boys born in the first and second quarters of the year had a significant physical advantage over their relatively younger peers. These findings have practical bearing if coaches use fitness tests for talent identification and team selection. Categorizing test performance based on rounded down values of whole-year age may disadvantage children born later in the selection year. These relatively younger children may be less to gain selection for teams or training programmes.
相对年龄效应（RAE）描述了个体的出生月份与其在运动中的表现水平之间的关系。在按年龄分组的运动中，用于选拔的截止日期之后，出生日期会出现聚集现象，人们假设相对年长的运动员可能比年轻的同龄人在成熟度和身体素质方面具有优势。然而，几乎没有任何此类优势的经验证据。本研究调查了学童的身体表现是否因他们出生的学年季度而有所不同。在 10 至 16 岁的儿童中测量了体重、身高、体重指数、心肺适能、力量和功率（n = 8550，53%为男性）。我们根据参考数据将测试表现表示为年龄和性别特定的 z 分数，年龄四舍五入到最接近的整岁，并且还表示为归一化的体重单位。然后，我们比较了这些值在每年出生季度之间的差异。在任何性别中，人体测量指标的差异都没有显著的主要影响。当以 z 分数表示时，与其他时间相比，在学年第一季度出生的女孩的握力明显更强。作为 z 分数，在学年第一季度和第二季度出生的男孩的所有指标都明显更高。与体重相比，在学年第一季度出生的男孩的心肺适能更高，而在第二季度出生的男孩的功率更高。当以 z 分数或相对于体重表示时，RAE 似乎不会对女孩的表现测试成绩产生重大影响。在学年第一季度和第二季度出生的男孩在身体素质方面比相对年轻的同龄人具有明显的优势。如果教练使用体能测试来选拔人才和组建团队，这些发现具有实际意义。根据整岁年龄的四舍五入值对测试表现进行分类可能会使在选拔年份后期出生的孩子处于不利地位。这些相对年轻的孩子可能不太可能被选拔加入球队或培训计划。
