Lumbar Extension Strengthening in Addition to Manual Therapy and Exercise for Chronic Low Back Pain

The goal of this clinical trial is to determine the effect of adding lumbar strengthening exercises to a program of manual therapy and motor control exercises (standard therapy) in adults with chronic low back pain (cLBP). Researchers will compare individuals with cLBP that receive lumbar extensor strengthening in addition to standard therapy compared to standard therapy alone to determine if there are differences in patient reported outcomes, lumbar multifidus thickness, low back endurance, and healthcare utilization between the groups. All participants will engage in 8-weeks of physical therapy, receiving manual therapy and motor control exercises. Those in the intervention group will have additional low back strengthening exercises.