A new study from The Ohio State University Wexner Medical Center examines what may cause chronic back pain in runners and the exercises to help prevent it.

The study, published in the Journal of Biomechanics, suggests that runners with weak deep core muscles are at higher risk of developing low back pain. And, unfortunately, most people’s deep core muscles aren’t nearly as strong as they should be.

To examine the role of the superficial and deep core muscles, researchers used motion detection technology and force-measuring floor plates to estimate muscle movements during activity.

What they found is that weak deep core muscles force more superficial muscles like the abs to work harder and reach fatigue faster. When those superficial muscles are doing the work the deep core should be doing, there are often painful consequences.

When your deep core is weak, your body is able to compensate in a way that allows you to essentially run lie normal. But that increases the load on your spine in a way that may lead to low back pain.

Experts say it’s common for even well-conditioned athletes to neglect their deep core, and there is a lot of misinformation online and in fitness magazines about core strength. Traditional ab exercises with a large range of motion, such as sit-ups or back extensions, will not give you the strong core needed to be a better runner.

Instead, Chaudhari says exercises such as planks that focus on stabilizing the core, especially on unstable surfaces, are what’s really going to make you a better runner.