most of us picture endless crunches and a burning feeling in the stomach. But your core is much more than your abs. It’s a group of muscles that wrap around your midsection and keep your spine steady

Start on your hands and knees, with your wrists under your shoulders and your knees under your hips. Reach your right arm forward and your left leg back, so that you form a long, straight line from your fingers to your toes. Keep your eyes on the floor and your hips level, as though a…