Objective
To evaluate the effects of back extensor strengthening exercise on improving the pain, activities of daily living (ADL) and bone mineral density in the chronic low back pain patients.

Method
21 patients with chronic low back pain participated in back school program. Before program, measurement of lumbar extensor strength with MedX^Ⱂ (Ocala, USA), visual analogue scale (VAS) for pain, level of ADL and bone mineral density (BMD) with DEXA (Lunar^Ⱂ, GE, USA) were done. For 12 weeks subjects had received the training for strengthening of back extensor and then, checked up with the above variables again.

Results
The results were as follows: 1) After 12 weeks of lumbar extensor strengthening program, isometric lumbar extensor strength was increased significantly (p＜0.01), 2) VAS and ADL were significantly improved from 5.1 to 3.3, and 8.1 to 9.9, respectively (p＜0.01), 3) BMD of lumbar spine were significantly improved from ⁣1.1 to 0.8 (p＜0.05)

Conclusion
Twelve weeks lumbar extensor strengthening program with pelvic stabilization may be the effective therapeutic program for patients with chronic low back pain. (J Korean Acad Rehab Med 2002; 26: 576-580)