In 1935 the Norwegian Workers Sports Federation, the AIF, decided to introduce the principle of ‘physical age' as a new method and a whole new philosophy for class division in sports competitions for children and youth. This meant to make the division of competitors not only on biological age, but also on height and weight. Based upon primary sources and research literature this paper will discuss the arguments leading to the introduction of this new way of organising children's sports and study the historical context enabling these ideas to succeed.

In short, the arguments for introducing ‘physical age' were to overcome obstacles seen to hinder children's participation in organized sport, as well as a more philosophical argument: to enable a level playing field, to create a more even and fair competition and give the children equal physical preconditions.

The context for this proposal was a central element in social history: The poverty of the working classes had physical outcomes on their children which influenced physical capacity and sports performances.

The idea of physical age came from educated and ideologically convinced physicians who held a more theoretical approach to children' sports and play. From the pioneering physicians' view the physical age principle would make it more tempting to join sports clubs. However, statements from various sources indicate that the principle of physical age was not so popular among the children themselves. The main issue seems to be that for the children, sport was not merely a physical contest, but a social encounter, as well.