Expertise Practice Design Talent ID

A 2 year longitudinal study of junior soccer players

Early specialization or early diversification?

Early specialization refers to children specialising in one sport from an early age. Think Tiger Woods or the Williams’ sisters. Early diversification refers to sampling multiple sports during childhood. Think Jordan Spieth or Scott Pendlebury (if you’re an Australian!).

Most of our knowledge of the development of expertise comes from experts retrospectively recalling their practice histories. And typically experts fall into one of the two categories.

Arne Gullich and colleagues advanced this methodology by incorporating a 2 year longitudinal assessment of skill, whilst also retrospectively assessing practice histories.

Participants included 11 year old soccer players from Germany. During time-point 1, when skill was first assessed, participants also completed a questionnaire regarding their sports practice before the age of 10. Two years later, their soccer skill was assessed again, and another questionnaire was administered to assess practice during the 2 year period. Soccer skill was assessed based on performance during 5 v 5 matches. Expert coaches rated their performance.

Following the second assessment of skill, participants were divided into 2 groups:

  1. Strong responders (SR) = greatest improvement over the 2 year period.
  2. Weak responders (WR) = least improvement over the 2 year period.

The two groups were matched for age, matchplay performance during the first assessment of skill, and physical attributes during the initial assessment.

There were three key findings.

1. Volume of organised soccer practice

The percentage of overall soccer practice that was considered “organised” was less for the strong responders (30% vs 43%).

2. Volume of non-organised soccer practice

The percentage of overall soccer practice that was considered “non-organised” was higher for the strong responders. Strong responders engaged in non-organised practice 2.1 times more than organised practice, whereas weak responders engaged in non-organised practice 1.3 more than organised practice. Non-organised soccer play before the age of 10 was linked with better matchplay performance at age 12.

3. Volume of organised practice in other sports

Strong responders participated in more organised practice in sports other than soccer.


The results support early diversification for junior soccer players. It was interesting to note that differences in practice histories before the age of 10 resulted in no differences in matchplay skill at age 11, but differences did occur at age 13. Hence, the benefits of diversification during early childhood might not become apparent for several years.

Soccer authorities should provide opportunities for children to participate in non-organised soccer practice. Additionally, soccer authorities should be open minded about children sampling multiple sports. Whilst it might take children’s attention away from soccer for a moment in time, the long-term benefits are likely to be significant.


Güllich, A., Kovar, P., Zart, S., & Reimann, A. (2017). Sport activities differentiating match-play improvement in elite youth footballers–a 2-year longitudinal study. Journal of sports sciences, 35(3), 207-215.


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