Investigation of relative age effect in racket sports

Objective: The purpose of the present study was to investigate relative age effect among competitive racket sports players in Turkey in 2018. Method: A total of 57476 racket sports players ages 5 to 85 were evaluated in the study. Of 57476 players, 17134 were badminton (7849 female and 9285 male), 13606 were table tennis (5164 female and 8442 male), 182 were squash (71 female and 111 male) and 26554 were tennis (12380 female and 14174 male) players. Players were divided into four quartiles by their birth months (Q1=January–March; Q2=April–June; Q3=July–September; Q4=October–December). Chi-square goodness-of-fit tests were used to investigate birth month distributions among quartiles. Each age category was evaluated separately and as a whole to determine bias in each sport. Furthermore, each analysis was repeated for both genders to define possible differences between genders. Additionally, Odds Ratios (OR) and 95% Confidence Intervals (95% CIs) were used to compare quartiles with each other. Results: As a whole, statistically significant distribution bias favoring Q1 was determined among racket sports players (χ²=1007.301, df=3, p=.000). Furthermore, statistically significant distribution biases were determined in badminton, table tennis and tennis (χ²=332.791, df =3, p=.000; χ²=152.970, df=3, p=.000; χ²=546.360, df=3, p=.000, respectively), while there was no such bias in squash (χ²=2.408, df=3, p=.492). With regard to gender, statistically significant biases favoring Q1 were determined in badminton, table tennis and tennis for both genders. Conclusion: The present study shows statistically significant relative age effect among competitive racket sports players in Turkey in 2018. Along with several suggestions proposed in the relevant literature, coaches are suggested to take relative age effect into consideration in talent identification and periodization processes. Keywords: relative age effect, racket sports, talent identification