Darwinian Selection Discriminates Young Athletes: the Relative Age Effect in Relation to Sporting Performance

Sports Medicine - Open

Table 3 Distribution and summary statistics for the whole athlete population and by sport type

Sport	Sex	Chi-squared statistics		Absolute distribution (N)				Relative distribution (%) (95% CI)
Sport	Sex	Χ²	P value	Total	T1	T2	T3	T1	T2	T3	V
All	Both	205.0	< 0.001	244 558	89 036	83 781	71 741	36.4 (36.2–36.6)	34.3 (34.1–34.4)	29.3 (29.2–29.5)	0.12
	Male	61.1	< 0.001	164 666	59 269	56 492	48 905	36.0 (35.8–36.2)	34.3 (34.1–34.4)	29.7 (29.5–29.9)	0.10
	Female	192.9	< 0.001	80 077	29 752	27 521	22 804	37.3 (36.9–37.6)	34.1 (33.8–34.5)	28.6 (28.3–28.9)	0.16
Physical	Both	2127.0	< 0.001	192 628	71 052	65 965	55 611	36.9 (36.7–37.1)	34.3 (34.0–34.5)	28.9 (28.7–29.1)	0.23
	Male	135.0	< 0.001	114 233	41 827	39 173	33 233	36.6 (36.3–36.9)	34.3 (34.0–34.6)	29.1 (28.9–29.4)	0.13
	Female	194.4	< 0.001	78 321	29 212	26 760	22 349	37.3 (37.0–37.6)	34.2 (33.8–34.5)	28.5 (28.2–28.9)	0.16
Skill	Both	12.7	0.002	51 930	17 984	17 816	16 130	34.6 (34.2–35.0)	34.3 (33.9–34.7)	31.1 (30.7–31.5)	0.09
	Male	13.2	0.001	50 433	17 442	17 319	15 672	34.6 (34.2–35.0)	34.3 (33.9–34.8)	31.1 (30.7–31.5)	0.09
	Female	1.6	0.442	1 486	540	491	455	36.3 (34.0–38.8)	33.0 (30.7–35.5)	30.6 (28.3–33.0)	0.13

Χ² chi-squared statistic, T tertile, V effect size, Cramer’s V
Parent population (national birth statistics) was set at expected distribution in chi-squared test
“Physical” includes Cross-country skiing, athletics, orienteering and alpine skiing. “Skill” includes E-sports and chess