Swimming Science Bulletin

Swimmers (N = 320) between the ages of 11 and 18 years were studied. A number of findings were developed, several of which reinforce previous works.

At a young age, faster swimmers are early or on-time maturers and, therefore, stronger and bigger.
High performance late maturers are likely to stay in the sport for a long time.
Changes in percent body fat become negligible and segment length growth stops for both males and females by the age of 16 years.
Before the age of 16, swimmers of both sexes experience very marked changes in physiology and anthropometric variables.
The greatest performance improvement for females occurs between the ages of 14 and 15 years, and for males between 15 and 16.
Training before 16 years of age should be primarily of a technical and base development nature (technique and aerobic endurance).
After 16 years of age and the establishment of a technique and aerobic base, training should stress i) anaerobic capacity and power, ii) technical racing skills, and iii) psychological skills.
Endurance capacity is fully developed by the age of 15 years. [In an earlier ICAR publication, the age of full development was reported as being that which coincided with puberty.]
Anaerobic characteristics are fully developed by 19 years of age.
Muscle power is fully developed by 18 years of age.

Implications. The features stressed here are known to most coaches. However, three are worthy of further discussion.

The periods of greatest performance improvement could serve as significant cut-off points for talent identification. If swimmers have not achieved very notable levels after those ages, then the selection of younger equal or marginally worse performers may be justified for training squads and teams.
A competitive program that is in concert with a developmental model is justified. It makes little sense to attempt to train a physical capacity in young children that has not started to develop (e.g., anaerobic capacity). For prepubertal swimmers, training programs should stress technique development and aerobic training. Competitive programs should also reflect a similar capacity demand.
Since improvement decelerates after 16 years of age, it would seem to be prudent to make that the highest age-group for competitions. That would mean discarding the 17 years group for both sexes. [At the 1992 Australian Age Championships, in 4 of 13 boys' events faster times were recorded by age groups younger than 17 while in the girls it was 12 of 13. Initially it might be advisable to retain the 17 years group for boys but not for girls.]