Swimming Science Bulletin

Age-group swimmers were measured to identify the order and rate of development of performance factors.

It is unusual to see an early-maturer become an elite world-class swimmer. The initial power and strength advantage is lost when normal and late-maturers achieve full growth. Late-maturers need to rely on technique to offset the early-maturer's physical advantage. It is to every swimmers' benefit to have a strong grounding in technique development prior to the onset of the adolescent growth spurt.
Muscle mass and power develop gradually after puberty. Early growth advantages are eventually lost. In the oldest age groups, the percentage of maximum power output that can be sustained during a race differentiates performance levels.
Anaerobic capacity is relatively inconsequential prior to puberty. At puberty the first growth surge in anaerobic capacity occurs. It then develops at a much slower rate, and then surges again as a final developmental stage.
Aerobic capacity is the first physiological factor to develop fully. It is established by the onset of the adolescent growth spurt (as early as 12 and as late as 15 years in males; for girls it is one to two years earlier). The major training emphasis prior to and during puberty should be endurance training. Once puberty is completed, the training emphasis should change gradually.

Implications. Several programming implications can be derived from this study.

All swimmers should be well-grounded in technique and aerobic training in the early years of serious swimming. This emphasis should proceed until the bulk of swimmers have exhibited their adolescent growth spurt. Early-maturers should be subjected to this program so they will not experience a technique deficit later on. [This would require current age-group racing and competition plans to be altered in a very significant manner.]
Endurance development will peak at the onset of puberty and will be maximal upon its completion.
Sprinting development should occur between the ages of 14-18 years for males, and 12-16 years for females. After that the determination of whether or not a swimmer is a sprinter can be made.
Power and strength development should occur in concert with sprinting development.
As swimmers grow, training should be general until puberty, then become gradually mixed, and finally be of specific anaerobic and general endurance nature after growth has been completed.
National training and competitive programs will have to be altered to better suit the growth patterns and capabilities of swimmers. Current competitive programs are not related to the capacities of age-group swimmers and do not serve to stimulate the best forms of development.