Over the years, there has boon much controversy regarding whether today's children and adolescents are fitter than their peers of the past and whether they are fitter If they live in the more affluent that the less affluent countries. This publications starts by examining data cumulated since the late 1950s on secular trends and geographic variability in pediatric fitness test performance of children and adolescents from 23 countries in North America, Europe, Asia, Australia, Africa, and the Middle East.