Before Adam Sharples became a molecular physiologist studying muscle memory, he played professional rugby. Over his years as an athlete, he noticed that he and his teammates seemed to return to form after the offseason, or even from an injury, faster than expected. Rebuilding muscle mass and strength came easy: It was as if their muscles remembered what to do. In 2018, Sharples and his research lab, now at the Norwegian School of Sport Sciences in Oslo, were the first to show that exercise