THE INDIVIDUAL ALWAYS GROWS
ACCORDING TO THE FEATURES THAT
COME WITH HIS AGE 

CALENDAR AGE
The real age.

BIOLOGICAL AGE
It can’t be measured with years, but rather with the growth, change and ageing of the physique. It stands in relation with the current state of the physique, the natural circumstances determining it, and social factors.
The duty of the coach is to give the children tasks which increase the chances of development. If players don’t get tasks that correspond to their level of growth, the trainer may face unsolvable problems later on.