Michael Jordan did not manage to get a spot in his high school team in the first year.

This topic is commented on in two different ways. On one hand, people believe that he devotedly practiced and became the best basketball player ever and, on the other hand, some cannot believe that the coach did not recognize his immense talent.

After high school Dennis Rodman worked at the airport in Dallas, but suddenly he grew tall and at the age of 25 he was chosen as the 27th player by Detroit Pistons.

Together they have won 3 NBA championships playing for Chicago Bulls. In addition, Jordan has won 3 championships with the Bulls, and Rodman 2 playing with Detroit Pistons.

Sport is filled with stories about top athletes who were unnoticed in their childhood.

There are two reasons for this:

Biological development of children is not linear

Children’s competitions are organised by age categories where age is measured by chronological rather than biological features

The consequence is the following:

At the championship of boys up to 16 years of age, the boys biologically aged between 14 and 18 play together.

In systems where the categories are determined by the even-year class, these differences can be even greater.

The table shows the number of players and the birth year of the semi-finalists at WCH U19,

The consequence is that even in the best organized national teams under 19, where biological differences should be almost equated, there is a much greater representation of older players.

We suppose that the more talented boys were not born in even years. Instead, the talent was equally divided in the even and odd years, but the system dismissed these boys.

Even in competitions in which children are not grouped in two-year cycles, but in one year, in the age between 15 and 16 there are 4 times more participants born in the first quarter, and at the age of 19, there is twice as many of them.

Inertia, or natural selection, will lead to a much greater dropout in boys born in odd years, and only an extra effort can change that fact.

IN THE 2009-10 SEASON, IN THE FC “REAL MADRID” FOOTBALL SCHOOL, THERE WERE 53.8% PLAYERS WHO WERE BORN IN THE FIRST QUARTER OF THE YEAR.

ARE THE TALENTED PLAYERS BORN BEFORE APRIL 1ST?

OR THESE BOYS ARE OLDER?

The problem of “odd year classes” also has children whose development is not linear, and these are children who are biologically younger than their generation until they go out of puberty.

Often such children have good biomechanics of movement, but as their body matures slower than the environment, they are ineffective in the game.

The coach’s job is to find a way of coaching these kids so they also undergo development. The coach needs to organize matches that will provide an extra opportunity for those children to play and create a positive emotional environment in the team to allow them to feel good and not to give up handball until their senior age.

Chronological age: number of years

Biological age: level of functional development of the child