You may not think your lower back has much of a role in running, but when you run, you hold your body vertical, of course—sometimes for a very long time.
Your core muscles support your spine and lower back, and your core, hips, glutes, and hamstrings together form one big stability machine, so weakness in any one of those muscles forces the others to take up the slack. If you have weak hip and gluteal muscles, for example, as they become fatigued during a run, your lower back is forced to work harder to keep you upright and stable, and you become vulnerable to injury.
What are the main problems runners face in their lower back? Here are three of the main issues:
1. Muscular pain that comes on suddenly in your lower back is indicative of a muscle spasm. Your muscles will feel as though they have locked up, and the pain can be severe and debilitating. You will not feel the shooting pain characteristic of sciatic or discogenic pain.