Arianne Cohen

“Exercise stimulates growth plates, by putting pressure on bone cells, forcing them to specialize and create new cells. Too much pressure, however, damages the growth plates, which are soft and fragile...The rule of thumb is that lifting one's own body weight (in push-ups,pull-ups, etc) is fine at any age, and kids over fifteen can lift weights.”

“Kids from small families grow about an inch taller than those from large families. This is true regardless of income and social class, because a body can't grow well while fighting off nine siblings' cold viruses.”