Professional athletes often spend hours in a gym working to build strong healthy muscles needed to keep them at the top of their game. But strong muscles help all humans maintain peak physical performance – the non-athlete, the young and the old – and can prevent frailty later in life, a condition that can exacerbate an illness and even shorten one's life. According to Charlotte Peterson, co-director of the Center for Muscle Biology at the University of Kentucky, "muscle powers health."