Comprehensive Manuals in Pediatrics are designed to broaden the prac­ titioner's clinical scope by providing a wide range of diagnostic and management skills ordinarily considered to be the exclusive domain of the specialists. Although the series as a whole constitutes a comprehen­ sive text in pediatrics, each volume stands on its own as a self-contained the busy practitioner. reference for In order to maintain a uniform style and coverage of each subject, each manual is usually written by no more than one or two authors. Each author is an acknowledged expert in his or her field and provides a comprehensive, up-to-date account of the topic under discussion. Practi­ cally oriented, each volume offers concise guidelines and courses of treatment. Michael Katz E. Richard Stiehm Preface Much knowledge has been generated in recent years by scientists investigating the triad: child-exercise-health. Yet little of this infor­ mation is available in pediatric textbooks, for application by the clinician. This book is intended to bridge the resulting gap.