Book excerpt: Every day scientists learn more about how the body adapts to the stress of running—and how various body systems contribute to running performance. Leading the charge is a fresh generation of brilliant young exercise physiologists including Ross Tucker and Jonathan Dugas, whose work has demolished many long-standing beliefs about running. Now Tucker and Dugas, whose blog, Science of Sport, has already created a devoted readership, join with esteemed fitness author Matt Fitzgerald to provide a captivating tour of the human body from the runner's perspective. Focusing on how runners at all levels can improve their health and performance, Runner's World The Runner's Body offers in a friendly, accessible tone, the newest, most surprising, and most helpful scientific discoveries about every aspect of the sport—from how best to nourish the runner's body to safe and legal ways to increase oxygen delivery to the muscles. Full of surprising facts, practical sidebars, and graphical elements, The Runner's Body is a must-have resource for anyone who wants to become a better—and healthier—runner.