"Don't worry about it," mothers often tell children complaining of leg aches. "It's just growing pains."
Or is it? Growing pains are interesting, for in one way they are real but in another way, they don’t really exist. Growing pains are minor, unspecified aches and pains (often in the arms or legs) reported by young children.
The pains are real, but they are not caused by the child's growing body. The process of growing is so slow that if there was any physical pain associated with aging, it would be stretched out over the course of months. In short, growing isn’t painful (unless you’re Bruce Banner turning into the Incredible Hulk!). Of course, we are all growing all the time, so strictly speaking growing pains could strike at any age (arthritis could be considered growing pains for the elderly).
Growing pains are typically not dangerous or harmful, but instead a convenient (if somewhat dismissive) "catch-all" folk diagnosis for the minor sprains, muscle exhaustion, and sore muscles that occasionally plauge active kids.