Resistance exercise is characterized by a voluntary muscle contraction of a body segment against an external resistance. It generates a number of effects on body composition, in particular muscle hypertrophy. In this book, Chapter One studies the effects of resistance and aerobic training on obesity, a worldwide epidemic with an alarming high prevalence. Chapter Two shows the effectiveness of resistance training on three diseases with rheumatic features. Chapter Three summarizes findings from a university-community-based resistance training program (with information sessions and social gatherings) that was designed for older people.