Many parents quickly rally behind their children when it comes to sports and can often be seen screaming from the bleachers unapologetically loud, obnoxious, and most importantly, proud. Spending hours in the park playing games and money on extra coaching to give your child a competitive edge may be something parents have no control over, unless they plan ahead on when to conceive. According to a recent study published in the International Journal of Sports Medicine, autumn-born babies, especially those born in October and November, are faster, fitter, and stronger than their counterparts.

Sporting development in children has long been attributed to the phenomenon of the relative age effect. This suggests athletes at the elite level are more likely to be born in the first three months after the eligibility cut-off date of a particular age group in sports, wrote author Malcolm Gladwell in this book Outliers: The Story of Success. For example, the eligibility cut-off age for age-class hockey is Jan. 1. Therefore, a boy who turns 10 on Jan. 2 could be playing on the same team as a boy who does not turn 10 until Dec. 31. The 12-month gap will most likely contribute to the difference in their physical maturity, gaining the older counterpart a competitive edge.

In an effort to determine if month of birth affects performance in three tests of physical function in children and adolescents, Dr. Gavin Sandercock, study leader and clinical physiologist at the Center for Sports and Exercise Science at Essex University, and his colleagues, analyzed data in a large cohort of boys and girls. A total of over 8,550 boys and girls, aged between 10 and 16 from 26 state schools in Essex, were all tested between 2007 and 2010 across the following measures of fitness: stamina, handgrip strength, and lower body power. The researchers gathered this data and expressed them relative to (whole year) age, then compared scores between calendar year birth months.

The findings revealed a child’s month of birth could contribute to significant differences to their levels of cardiovascular fitness, muscle strength, and their ability to accelerate, which are factors that determine how good someone is at a sport. Sandercock and his team of researchers found the November-born children had the most stamina, and power, and were the second strongest. Those born in the month of October were almost as fit, scoring highest for strength and coming third for power, while December children closely followed, The Guardian reported.

Children born in April were the least fit, compared to those in June. The findings highlight children born during the school year months not only have an academic advantage, but they now can have a competitive advantage in sports. These month gaps could be used to predict which of these children a top-athlete since became, "selection into elite sports may often depend on very small margins or differences in an individual's physical performance,” according to the study paper.

The authors believe a contributing factor to autumn-born children being sportier than their counterparts could be due to sunlight exposure during the summer months, toward the end of pregnancy. "Seasonal differences in intrauterine vitamin D concentrations seem most plausible," they wrote. The Vitamin D Council suggests on days that you get full body sun exposure, pregnant mothers do not need to take a supplement. Vitamin D is important for a baby’s growth and development.

A surprising piece of data found children born in September and October tended to live in more affluent areas. “It would be interesting to find out whether more well-off families are deliberately timing pregnancies to make sure their children have the advantage at school,” said Sandercock, in the University of Essex news release. The research team wants to do more research in this field and explore the relative age effect to confirm their findings.

Until then, those who have a competitive edge can bask in the glory of their natural born talent. After all, it’s backed by science.

 

Source: Cohen DD, Oqunleye AA, Parry DA et al. Athletic Performance and Birth Month: Is the Relative Age Effect More than just Selection Bias? International Journal of Sports Medicine. 2014.