Most human beings have the largest number of growth hormones from age 14 to around 24. Then these growth hormones gradually decrease in number which is part of the aging process. This can been done with a broom handle with no weight. I think basic gymnastics gives them all of the above exercises plus teache s them to deal with body balance and overall body coordination. I have watched several of my grandchildren doing beginning gymnastics and it seems to me that a basic gymnastic program would do wonders for early body development particularly the upper body .
Swimming is also a good upper body and overall muscle developer for young bodies.
Starting individuals early will help balance tendon and ligament growth with muscle growth so, as they grow older they will not have as many injuries. Next, there are three things human beings all need to develop a productive and healthy life style. These are physical, mental and emotional toughness. These 3 are closely inter-related so starting physical fitness early in life will help young human beings develop mental and emotional toughness. as well as physical toughness. It is a know fact that yout h in the US is becoming less fit physically so starting children at the age of 6 or 7 on the road to a physically active life is really important to the overall health of the human beings in this country.