Heed your body’s warning signals to avoid injury As classic as legwarmers and Jane Fonda workout videos is the adage, “No pain, no gain.” But how do you know if you’re making progress or courting trouble? The most common form of pain we associate with physical activity is delayed onset muscle soreness, or DOMS. You’ll usually feel this soreness a day or two after beginning an exercise regimen, increasing the intensity of an existing routine or targeting a fresh set of muscles. If you’re a man over age 45 or a woman over age 55, or if you have an…