Research shows that there are critical or sensitive periods during growth and development where performance skills (strength, stamina, speed, coordination) have accelerated adaptation to training. Improvement can still be made outside of these critical periods but progress is much greater if training is synchronized within these periods. Plasticity is another term used to refer to this adaptation. A similar example would be learning a foreign language. For example, my grandfather and great grandfather moved to the United States from Italy when my grandfather was 7 or 8 years old. Although they both had the same length of time in the United States, after thirty years my great grandfather still had a very heavy Italian accent and was difficult to understand while my grandfather had no accent at all. Why the difference? Plasticity. My grandfather was exposed to English during critical periods of language development. Most sports fall into what is called a late specialization model which is divided into six stages.

• Stage 1: Fundamental - age 6-9 for males, 6-8 for females

  Objective: Learning all fundamental movement skills.

  These movement skills should be practiced and mastered before sport specific skills are introduced. Participation in a variety of sports is recommended. The critical period for speed development occurs from age 6-8 for females and 7-9 for males. Agility should also be trained during this period.

• Stage 2: Learning to train - age 9-12 for males, 8-11 for females

  Objective: Learn all fundamental sport skills.

  Skipping the fundamental and specialized skill development will most likely limit future success in sports. This is the most important period for motor development. Kids are ready to learn general sports skills that are essential to athletic development and success. This is the critical period for developing motor coordination.

• Stage 3: Training to train - age 12-16 for males, 11-15 for females

  Objective: Build aerobic base, begin strength building and continue sports specific skill development.

  Critical period for aerobic and strength training. Flexibility is also important in this stage. Females have two critical periods for strength training. The first is immediately after the growth spurt and the second begins at onset of menarche. For males it is 12-18 months after growth spurt. Athletes who miss this critical period will not reach their full potential. The main reason why many athletes plateau during later stages in their careers is because of an over emphasis on competition instead of on training during this critical period of development. Stage 2 and 3 are the most important in athletic development.

• Stage 4: Training to compete - age 16-18 for males, 15-17 for females

  Objective: Optimize fitness preparation and sport, individual and position specific skills as well as performance.

  This stage begins after Stage 3 goals have been met. Technical development can be individually tailored. Address individual strengths and weaknesses.

• Stage 5: Training to win - age 18 and over for males, 17 and over for females

  Objective: Maximize fitness preparations for individual and position skills.

  This is the final phase of athletic preparation. Training is focused on maximizing performance.

• Stage 6: Retirement/Retention

  Objective: Retain athletes for coaching and development of young athletes.

SUMMARY:

Although these critical periods are divided by ages, maturational levels are more appropriate. We have seen 17 years-olds who still need development in the earlier stages before progressing on to the more advanced training.