Low-back pain is a potentially debilitating issue that affects most active people at some point in their lives. One major downside of having low-back pain is how difficult it is to exercise and achieve your fitness goals, such as finally getting that flat tummy you’ve always wanted. Luckily, there is one exercise that can reduce low-back pain while simultaneously flattening your stomach—the plank. Because the plank exercise requires minimal movement while contracting all laye