Sleep is the most underrated performance enhancer. A new study of marathoners found that those who added a daily 20-minute nap improved recovery speed by 35% and cut injury risk in half. No expensive gear. No supplements. Just horizontal rest. Coaches are now scheduling “nap blocks” into training camps. The science is simple: deep sleep releases human growth hormone, which repairs microtears in muscles. Sprints and weights build strength. Sleep locks it in. The new mantra among Olympians: train hard, eat clean, sleep like a champion.