Comparison of the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles between community-dwelling older overweight and normal-weight women.

Objective: This study compared the masses and amounts of intramuscular non-contractile tissue of multiple trunk and lower extremity muscles measured using an ultrasound imaging device, as well as sagittal spinal alignment and mobility and balance ability, between older overweight and normal-weight women classified based on body mass index (BMI).

Methods: Thirty-seven community-dwelling older women were classified as normal-weight (NW) (n = 28) and overweight (OW) (n = 9) groups according to BMI. The thicknesses and echo intensities of the trunk and lower extremity muscles were assessed using an ultrasound imaging device. The sagittal spinal alignments in the standing and prone positions were also evaluated using a Spinal Mouse. Mobility and balance ability were also measured based on the usual and maximal walking speeds and timed up-and-go (TUG), five-chair-stand, and one-legged stance (OLS) times.

Results: We observed showed significantly greater thicknesses of the rectus abdominis, gluteus maximus, medius, and vastus lateralis muscles in the OW group compared to those in the NW group. The usual and maximal walking speeds and OLS time were significantly lower and the TUG time was significantly higher in the OW group than those in the NW group. The other factors did not differ significantly between the groups.

Conclusions: Our results suggested higher masses of the rectus abdominis, gluteus maximus, medius, and vastus lateralis muscles in community-dwelling older overweight women compared to normal-weight women. However, our findings also indicated reduced mobility and balance ability in older women who were overweight compared to older women who were not.