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

Jakobsson, Johan; Julin, A. Lennart; Persson, Glenn; Malm, Christer

doi:10.1186/s40798-021-00300-2

Sports Medicine - Open

Table 4 Distribution and statistics summary by sport and selected athletic events

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

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
Cross-country skiing^a	Male	47.0	< 0.001	73 381	26 521	25 330	21 530	36.1 (35.8–36.5)	34.5 (34.2–34.9)	29.3 (29.0–29.7)	0.11
Cross-country skiing^a	Female	61.2	< 0.001	50 684	18 571	17 369	14 744	36.6 (36.2–37.1)	34.3 (33.9–34.7)	29.1 (28.7–29.5)	0.13
Cross-country skiing^b	Male	23.2	< 0.001	8781	3297	2948	2 536	37.5 (36.5–38.6)	33.6 (32.6–34.6)	28.9 (27.9–29.8	0.16
Cross-country skiing^b	Female	41.9	< 0.001	2596	1055	875	666	40.6 (38.8–42.5)	33.7 (31.9–35.5)	25.7 (24.0–27.4)	0.25
Cross-country skiing^c	Male	14.4	0.007	582	243	202	137	41.7 (37.7–45.7)	34.8 (31.1–38.8)	23.5 (20.2–27.1)	0.28
Cross-country skiing^c	Female	8.9	0.012	361	153	120	88	42.5 (37.6–47.7)	33.1 (28.5–38.2)	24.3 (20.2–29.0)	0.28
All athletics events	Male	136.3	< 0.001	6992	2861	2387	1744	40.9 (39.8–42.1)	34.1 (33.0–35.3)	24.9 (23.9–26.0)	0.26
All athletics events	Female	145.1	< 0.001	7511	3108	2494	909	41.4 (40.3–42.5)	33.2 (32.1–34.3)	25.4 (24.4–26.4)	0.26
Athletics 100 m	Male	81.8	< 0.001	1266	584	416	266	46.1 (43.4–48.9)	32.9 (30.3–35.5)	21.0 (18.9–23.3)	0.36
Athletics 100 m	Female	55.1	< 0.001	976	444	320	212	45.5 (42.4–48.6)	32.8 (29.9–35.8)	21.7 (19.2–24.4)	0.34
Athletics discus	Male	28.5	< 0.001	664	271	252	141	40.8 (37.1–44.6)	38.0 (34.3–41.7)	21.2 (18.3–24.5)	0.32
Athletics discus	Female	19.7	< 0.001	714	303	237	174	42.4 (38.9–46.1)	33.2 (29.8–36.7)	24.4 (21.4–27.7)	0.29
Orienteering	Male	15.8	< 0.001	24 239	8806	8226	7207	36.3 (35.7–36.9)	33.9 (33.3–34.5)	29.7 (29.2–30.3)	0.11
Orienteering	Female	28.0	< 0.001	16 925	6231	5824	4870	36.8 (36.1–37.6)	34.4 (33.7–35.1)	28.8 (28.1–29.5)	0.14
Alpine skiing	Male	2.0	0.367	258	99	80	79	38.1 (32.7–44.4)	31.0 (25.7–36.9)	30.6 (25.3–36.5)	0.21
Alpine skiing	Female	1.4	0.491	244	94	78	72	38.5 (32.6–44.8)	32.0 (26.4–38.1)	29.5 (24.2–35.5)	0.20
E-Sport	Male	11.4	0.003^d	45 871	15 793	15 848	14 230	34.4 (34.0–34.9)	34.5 (34.1–34.9)	31.0 (30.6–34.0)	0.09
E-Sport	Female	2.0	0.373	1159	421	382	356	36.3 (33.6–39.1)	33.0 (30.3–35.7)	30.7 (28.1–33.4)	0.14
Chess	Male	10.8	0.005	4562	1649	1471	1442	36.1 (34.8–37.6)	32.2 (30.9–33.6)	31.6 (30.3–33.0)	0.16
Chess	Female	0.3	0.86	327	119	109	99	36.4 (31.4–41.8)	33.3 (28.4–38.6)	30.3 (25.6–35.5)	0.12

X² chi-squared statistic, V effect size, Cramer’s V
Parent population (national birth statistics) was set at expected distribution in chi-squared test
^aDatabase retrieved from “SSF-Timing” and includes recreational, competitive and elite skiers
^bData retrieved from www.skidresultat.se, and includes recreational, competitive and elite skiers
^cDataset of FIS-registered (elite) cross-country skiers
^dInversed RAE

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