In recent, years that has been a dramatic increase in the number of kids experiencing acute and overuse injuries.
There are physical and physiological differences between kids and adults that may make them more susceptible to injury.  Children have larger surface area to mass ratio, larger heads proportionately, and may be too small for some protective equipment; cartilage may be immature and more vulnerable to stresses.  Researchers note anecdotally that kids affected by heel pain (Sever's Disease) are typically highly active and that symptoms often presented at the beginning of the sport season and while the child is experiencing a growth spurt.  Researchers also suggest the repetitive impact force that occurs when the heel strikes the ground during movement also contributes to the condition.  There is no research evidence that shoes are to blame, but instead activity level is a contributing factor.  There is also no evidence to support that size, weight, and activity levels increase risk for Sever's disease.  No specific foot structure (arch, size, pronation, etal) or type of shoe worn has been directly related to the symptoms.