They were all summer children. They had shining hair and brown arms and bare legs, and as I watched them, under a blue sky in the dense heat of four August afternoons, nothing was serious. They had come together, more than a thousand of them, for a cheerleading clinic given each summer on the campus of Southern Methodist University. This clinic is one of 200 the National Cheerleaders Association holds throughout the United States, but it is the largest of the 25 in Texas and attracts squads from high schools all over Texas, Oklahoma, New Mexico, and even from as far away as Kansas City, Missouri.