Low back pain patients demonstrate increased hip extensor muscle activity during standardized submaximal rotation efforts.
METHODS
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.


BACKGROUND
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.


CONCLUSIONS
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.
Pirouzi
Soraya
S
School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia.
Hides
Julie
J
Richardson
Carolyn
C
Darnell
Ross
R
Toppenberg
Rowena
R
D000328:Adult; D001415:Back; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D004576:Electromyography; D005260:Female; D006615:Hip; D006801:Humans; D007537:Isometric Contraction; D017116:Low Back Pain / Q000503:physiopathology*; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012399:Rotation