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Low Back Pain Patients Demonstrate Increased Hip Extensor Muscle Activity During Standardized Submaximal Rotation Efforts

Pirouzi, Soraya, MS; Hides, Julie, PhD; Richardson, Carolyn, PhD; Darnell, Ross, PhD; Toppenberg, Rowena, M Phty St

doi: 10.1097/01.brs.0000250076.74366.9d
Occupational Health/Ergonomics

Study Design. A comparative study of trunk and hip extensor muscle recruitment patterns in 2 subject groups.

Objective. To examine for changes in recruitment of the hip and back extensor muscles during low level isometric trunk rotation efforts in chronic low back pain (CLBP) subjects by comparison with matched asymptomatic control subjects.

Summary of Background Data. Anatomic and biomechanical models have provided evidence that muscles attaching to the thoracolumbar fascia (TLF) are important for providing stabilization to the lumbopelvic region during trunk rotation. This has guided rehabilitation programs. The muscles that link diagonally to the posterior layer of the TLF have not previously been examined individually and compared during low-level trunk rotation efforts in CLBP patients and matched controls.

Methods. Thirty CLBP patients and 30 matched controls were assessed using surface electromyography (EMG) as they performed low-level isometric rotation efforts while standing upright. Muscles studied included latissimus dorsi, erector spinae, upper and lower gluteus maximus, and biceps femoris. Subjects performed the rotation exertion with various levels of external trunk support, related to different functional tasks.

Results. EMG results demonstrated that subjects with CLBP had significantly higher levels of recruitment for the lower and upper gluteus maximus (P < 0.05), hamstrings (P < 0.05), and erector spinae muscles (P < 0.05) during rotation to the left compared with the control subjects.

Conclusion. This study provided evidence of increased muscle recruitment in CLBP patients when performing a standardized trunk rotation task. These results may have implications for the design of therapeutic exercise programs for CLBP patients.

Thirty asymptomatic and 30 CLBP patients were assessed using surface EMG on the low back and hip extensor muscles, during low level isometric rotation efforts in a standing position. CLBP patients demonstrated significantly higher activity levels in gluteus maximus, hamstrings, and erector spinae muscles than the matched control subjects.

From the School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia.

Acknowledgment date: April 5, 2006. First revision date: July 10, 2006. Second revision date: August 8, 2006. Acceptance date: August 10, 2006.

The manuscript submitted does not contain information about medical device(s)/drug(s).

No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Address correspondence and reprint requests to Julie Hides, PhD, Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia, 4072; E-mail:

© 2006 Lippincott Williams & Wilkins, Inc.