Article

OBJECTIVE: To determine whether multifidi size, intramuscular fat, or both, are
associated with self-reported and performance-based physical function in older
adults with and without chronic low back pain (LBP).
DESIGN: Case-control study.
SETTING: Individuals participated in a standardized evaluation in a clinical
laboratory and underwent magnetic resonance imaging (MRI) of the lumbar spine at
a nearby facility. PARTICIPANTS: A volunteer sample of community-dwelling older
adults (N=106), aged 60 to 85 years, with (n=57) and without (n=49) chronic LBP
were included in this secondary data analysis. INTERVENTION: Average right-left
L5 multifidi relative (ie, total) cross-sectional area (CSA), muscle-fat
infiltration index (MFI) (ie, a measure of intramuscular fat), and relative
muscle CSA (rmCSA) (ie, total CSA minus intramuscular fat CSA) were determined
from MRIs. Linear regression modeling was performed with physical function
measures as the dependent variables. Age, sex, and body mass index were entered
as covariates. The main effects of L5 multifidi MFI and rmCSA, as well as their
interaction with group assignment, were compared as independent variables. MAIN
OUTCOME MEASURES: Medical Outcomes Study 36-Item Short-Form Health Survey
physical functioning subscale, timed Up and Go, gait speed, and fast stair
descent performance. RESULTS: Interaction terms between L5 multifidi MFI and
group assignment were found to be significant contributors to the variance
explained in all physical function measures (P</=.012). Neither the main effect
nor the interaction with group assignment for L5 multifidi rmCSA significantly
contributed to the variance explained in any of the physical function measures
(P>.012). CONCLUSIONS: Among older adults with chronic LBP of at least moderate
intensity, L5 multifidi muscle composition, but not size, may help to explain
physical function.
CI - Copyright (c) 2016 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS