They are born with them.
by exercising them
Anyone who is healthy enough to tolerate exercise can grow muscles. From young children to senior citizens.
Children primarily use their diaphragm and intercostal muscles to breathe. The diaphragm contracts and moves downward, expanding the chest cavity, while the intercostal muscles between the ribs help to further expand the chest for breathing in.
training you muscles will not make your children stronger. One scientist thought that giraffes got long necks by stretching them all the time and automatically their offspring got the long neck. Getting stronger only makes you strong, not your children.
Children normally use their diaphragm and intercostal muscles to breathe. The diaphragm is the main muscle responsible for breathing, while the intercostal muscles help expand and contract the chest cavity during respiration.
For growth and to build up their protein tissue
An orthopodist specialize in conditions and disease that affect the bones and muscles, usually in children.
Low muscle tone in the facial muscles
No, because when your a kid your muscles aren't fully developed as they would when your a teenager.
One answer could be Rene Descartes.
pain in muscles or joints sometimes experienced by children and often attributed to rapid growth
too close to the sciatic nerve