Everyone can benefit from building strength in their core, meaning the group of muscles in the abdomen, back, hips and pelvis. Having a strong core takes pressure off nearby joints and helps the body to maintain good posture. The most important thing our core musculature does is give us a brace with movement, says Cleveland Clinic physical therapist Jennifer Smith, PT, DPT, OCS. We need this stability for greater mobility. When evaluating patients with low back pain or pain in their lower extremities, Smith examines their core strength.