Background: Intramuscular adipose tissue (IMAT) of the lower extremity is a strong negative predictor of mobility
function. Variability in temporal gait factors is another important predictor of mobility function. The purpose of this
study was to examine the relationships between IMAT in the hip and thigh muscles, balance, and temporal gait variability
in older adults.
Methods: Forty-eight healthy community dwelling older adults (74 +/- 1 year) underwent a CT scan to quantify IMAT in
the gluteus maximus (Gmax), gluteus medius/minimus (Gmed/min), hamstrings, vastus lateralis, and adductor muscles.
Temporal Gait measures were collected on a GAITRite walkway and gait variability was determined by calculating intraindividual
standard deviations. Individuals were divided by tertiles of temporal gait variability into categories of high,
medium, and low variability. Differences in the IMAT of the hip abductors were calculated for those with high and low
gait variability and partial correlations for gait variability and all muscle composition measures were determined for all
variables with normalized gait speed as a covariate.
Results: Gmed/min IMAT was greater in those with higher gait variability compared to those with lower gait variability
(p<0.05). Gmed/min IMAT was related to stride width variability (r=0.30, p<0.05). Gmax IMAT was also related to time
variability of swing (r=0.42), stance (r=0.26), double limb support (r=0.43), double support loading (r=0.44), and double
support unloading (r=0.50) (all p<0.05).
Conclusion: Increased IMAT in the proximal hip muscles, particularly the hip abductors, was associated with increased
gait variability and poorer balance. These findings may have implications for the assessment and treatment of balance and
falls such that interventions for enhancing balance and mobility among older individuals should take into account the importance
of gluteal muscle composition.