Summary of a study looking at represenation and results of athletes born in each month in Olympic weightlifting.
953 Olympic weightlifters (358 females, 595 males) from 5 Olympic Games (2000, 2004, 2008, 2012, 2016).
Comparison of birth-date of Olympic weightlifters who competed in the Olympic Games to the worldwide birth-date distribution for general population.
- date of birth (relative age effects)
- weight class:
- lightweight (48, 53, 58 kg)
- middleweight (63, 69 kg)
- heavyweight (75, 75+ kg)
- lightweight (56, 62, 69 kg)
- middleweight (77, 85, 96 kg)
- heavyweight (105, 105+ kg)
- success: medalist/non-medalist
- Total, snatch, clean & jerk results
- The relative age effects (month of birth effects) were present for Olympic weightlifters in general with over-representation in January, and under-representation in June, September and November.
- The relative age effects were present for males in each weight class with over-representation in January, and under-representation of lightweight men in November.
- The relative age effects were present for females in lightweight with over-representation in January, but not in middleweight or heavyweight (this can be biased due to the small sample size).
- No relative age effects were found for snatch, clean & jerk and total lifter kg in both women and men.
- Distribution of male medalists matched global birth distribution (no relative age effects), but for non-medalists there was an over-representation in January, and under-representation in May, October and November.
- For women, there was an over-representation in both medalists and non-medalists in January and under-representation in September.
Take home message
Kollars JM, Taber CB, Beyer KS. Relative Age Effects in Elite Olympic Weightlifters. The Journal of Strength & Conditioning Research. 2021 May 1;35(5):1223-8.