Book excerpt: The Encyclopedia of Exercise Medicine is intelligently structured, easy accessible and user-friendly: A-Z format, clear, concise language and uniform essay structure as well as extensive cross references between keywords and related articles enables efficient searches in a user-friendly manner both for experts and newcomers. It is intended to be a comprehensive up-to-date data base on the adaptation of the human body to exercise and on the therapeutic use of exercise with up to 2,000 keywords. It covers all aspects within the full range of modern exercise medicine of each particular scientific discipline (cancer, parasitology, aging, etc.). This includes information on methodological approaches to measuring the principle components of motor fitness, and practical aspects of their enhancement by trainings regimes as well as by nutrition and the application of drugs. Such a wide range of entries, all written by leading experts in their respective fields, will therefore address both the basic/clinical scientist as well as the practitioner. Moreover, the Encyclopedia of Exercise Medicine is aimed at people in related fields, health care professionals, physiotherapists, trainers, students, informed athletes and interested laypersons. It is available both in print and as a fully searchable and hyperlinked electronic online edition.