Are modern men and women born to run, or must our 21st-century bodies be carefully cross-trained to stay fit and healthy?
When it comes to care and training of today's distance runner, expert opinions are mixed.
Jay Dicharry, author of the new book Anatomy for Runners, believes that to be a better runner, running is not enough.
"Running is typically a one-dimensional sport," says Dicharry, a physical therapist. "You're basically just moving forward; you're not really developing as a true athlete."
Studies have shown that one-third of runners are hurt every year. His book focuses on identifying weaknesses, with detailed tools for gait analysis, tips for injury prevention and corrective exercises that range from yoga-like toe strengtheners to stability work.
Comparing the body to a car, Dicharry says that while many books focus on the runner's cardiovascular system, or engine, he zeroes in on the biomechanical body, or chassis. "The more stable the chassis, the more efficient you can be."