This article was reviewed by Craig Primack, MD, FACP, FAAP, FOMA. “Right to the core,” “core values,” and “hardcore.” These little idioms highlight just how vital the concept of “core” is in our lives ...

If you’ve ever held a plank, paused at the bottom of a squat or pressed your palms together in front of your chest, you’ve done an isometric exercise. Ta-da! These holds might look simple — after all, ...