When I played sports in high school, I did not train enough. Do not let your child do the same. Depending on age, my training is different. Under 14, we will not be doing any heavy weight training. Over 14, we will be doing hardcore weight and cardio training.
As stated on another page, I am a football coach so I do dedicate time to training on specific sports. My two specialies are football and basketball.
For kids from 7-12, I will work on fundamentals and we will need to take training to a baseball field.