Article

OBJECTIVES: To determine the activation of the gluteus medius in persons with
chronic, nonspecific low back pain compared with that in control subjects, and to
determine the association of the clinical rating of the single leg stance (SLS)
with chronic low back pain (CLBP) and gluteus medius weakness. DESIGN:
Cohort-control comparison. SETTING: Academic research laboratory. PARTICIPANTS:
Convenience sample of people (n=21) with CLBP (>12wk) recruited by local
physiotherapists, and age- and sex-matched controls (n=22). Subjects who received
specific pain diagnoses were excluded. INTERVENTIONS: Not applicable. MAIN
OUTCOME MEASURES: Back pain using the visual analog scale (mm); back-related
disability using the Oswestry Back Disability Index (%); strength of gluteus
medius measured using a hand dynamometer (N/kg); SLS test; gluteus medius onset
and activation using electromyography during unipedal stance on a forceplate.
RESULTS: Individuals in the CLBP group exhibited significant weakness in the
gluteus medius compared with controls (right, P=.04; left, P=.002). They also had
more pain (CLBP: mean, 20.50mm; 95% confidence interval [CI], 13.11-27.9mm;
control subjects: mean, 1.77mm; 95% CI, -.21 to 3.75mm) and back-related
disability (CLBP: mean, 18.52%; 95% CI, 14.46%-22.59%; control subjects: mean,
.68%; 95% CI, -.41% to 1.77%), and reported being less physically active.
Weakness was accompanied by increased gluteus medius activation during unipedal
stance (R=.50, P=.001) but by no difference in muscle onset times. Although
greater gluteus medius weakness was associated with greater pain and disability,
there was no difference in muscle strength between those scoring positive and
negative on the SLS test (right: F=.002, P=.96; left: F=.1.75, P=.19).
CONCLUSIONS: Individuals with CLBP had weaker gluteus medius muscles than control
subjects without back pain. Even though there was no significant difference in
onset time of the gluteus medius when moving to unipedal stance between the
groups, the CLBP group had greater gluteus medius activation. A key finding was
that a positive SLS test did not distinguish the CLBP group from the control
group, nor was it a sign of gluteus medius weakness.
CI - Copyright (c) 2014 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS