Is the limit in the body’s physiology or in the mind, or in a combination of the two? (Mine is surely in the mind, I haven’t gone close to limits of my body for running, swimming or cycling.) An exploration of research on limits of endurance performance and how to stretch them. I really enjoyed the middle and last section of the book—covering various physiological elements affecting the body, and the research on identifying and stimulating areas of the brain to stretch performance.

If you can fill the unforgiving minute
With sixty seconds’ worth of distance run,
Yours is the Earth and everything that’s in it…

—If, by Rudyard Kipling