Article

Lumbar stabilization exercise programs (LSEP) produce positive
effects on clinical outcomes, but the underlying mechanisms remain relatively
unexplored. Psychological and neuromuscular mechanisms can be involved, such as a
better activation of the lumbar multifidus, which represents one possibility.
OBJECTIVES: To determine the following: (1) the effect of an LSEP on lumbar
multifidus muscle thickness and activation, as measured with rehabilitative
ultrasound imaging (RUSI), in patients with low back pain (LBP); (2) the
correlation between RUSI measures and any change in clinical outcomes following
the LSEP; and (3) the reliability of RUSI measures in control subjects over 8
weeks. DESIGN: One-arm clinical trial with healthy subjects as a control group;
reliability study. SETTING: LSEP delivered in a clinical setting; outcomes
measured in a laboratory setting. PARTICIPANTS: A total of 34 patients with
nonacute LBP and 28 healthy control subjects. METHODS: Outcomes were measured
before and after an 8-week LSEP in patients with LBP, and at the same time
interval (without treatment, to assess reliability) in control subjects. MAIN
OUTCOME MEASUREMENTS: Pain numeric rating scale, Oswestry Disability Index
(function), as well as RUSI measures for the lumbar multifidus (LM) muscles at 3
vertebral levels (L5-S1, L4-5, and L3-4) during rest (static) and dynamic
contractions (percent thickness change). RESULTS: Patients did not show
systematic changes in RUSI measures relative to controls, even though RUSI
impairments were observed at baseline (dynamic measure at L5-S1) and even though
patients had significant improvements in pain and disability. Correlational
analyses with these clinical outcomes suggested that patients had reduced muscle
thickness at baseline that was associated with a greater reduction in disability
following LSEP; however, LM activation measured at baseline showed the opposite.
Static RUSI measures showed excellent reliability at the L4-5 and L3-4 levels,
whereas dynamic measures were not reliable. CONCLUSIONS: Patients showed less
muscle activation than controls at baseline (L5-S1 level), but the LSEP did not
normalize this impairment. The links between RUSI measures and the change in
clinical outcomes during LSEP should be further explored. This clinical trial has
been recorded in the International Standard Registered Clinical/soCial sTudy
Number (ISRCTN) registry (ID: ISRCTN94152969). LEVEL OF EVIDENCE: II.
CI - Copyright (c) 2018 American Academy of Physical Medicine and Rehabilitation.
Published by Elsevier Inc. All rights reserved.

Langue : ANGLAIS