Distributional characteristics of relative age in china football players

Introduction

According to Barnseley, Thompson, and Legault [1], relative age refers to the difference of age between individuals in the same age group is referred to as relative age, and its consequence is known as the Relative Age Effect (RAE). A remarkable amount of studies have shown the existing of RAE in various sports [2]. However, the question that whether the RAE is elaborated in different cultural background or sport system or not has not been well discussed. To validate the RAE within China sport system, the distributional characteristics of relative age of Chinese football players is examined in the present paper.

Methods

The birth dates of 811 male football players from 27 clubs are collected. All the clubs took part in the China football League A and B 2002. The distributional characteristics of 790 valid data are examined with Chi-square method.

Results

The distribution of birth date of 790 participants is cited in table 1.

Table 1. Distribution of birth month among China football players.

Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Frequency	121	73	76	75	64	68	58	58	58	50	50	39
Proportion(%)	15.3	9.2	9.6	9.5	8.1	8.6	7.3	7.3	7.3	6.3	6.3	4.9

A Chi-square method indicates a significant difference (c2 = 71.33, df = 11, P = 0.000 )among the birth date (month) of China football players: the number of athletes who have greater relative age is significantly higher than those who have less relative age. With regards to the birth quarter, this trend get more cleared (table 2): the frequency of observed cases decreases according to the quarter.

Table 2. Distributional characteristics of birth quarter of Chinese football players.

League	Birth Quarter				Sum	x2	Sig
	1st Quarter	2nd Quarter	3rd Quarter	4th Quarter
A	135	122	93	75	425	20.96	P < 0.001
B	135	85	81	64	365	30.69	P < 0.001
Sum.	270	207	174	139	790	47.19	P < 0.001

Discussion/ Conclusions

The results from Chinese football players reveal that the athletes who have greater relative age (in the present study, have an earlier birth month) will have greater possibility to engage in top level of the sport. It is discussed here that, the RAE could be also observed within China sport system. However, studies from various sports are expected to provide solid conclusion. The Theory of Deliberate Practice (DPT) from Ericsson and his colleagues [3] is suggested to be a potential explain of this cross-cultural commonalities on RAE.

References

1. Barnseley, R. H., Thompson, A. H., & Legault, P. (1992). International Review for the Sociology of Sport, 27, 77-87.
   
2. J. Musch & S. Grondin (2001). Developmental Review, 21, 147-167.
   
3. Ericsson, K. A., Krampe, R., & Tesch-Roemer, C. (1993 Psychological Review, 100, 363-406.