Trunk muscles may be an overlooked region of deficits for adults following a lower-limb amputation. A study of sedentary adults sought to determine the extent that trunk muscle deficits are associated with physical function following amputation.
Twenty-five sedentary adults with unilateral transtibial amputations and 14 with unilateral transfemoral amputations were recruited for a cross-sectional research study. Participants underwent a clinical examination that included ultrasound imaging of the lumbar multifidi muscles, the modified Biering-Sorensen Endurance Test (mBSET), and performance-based measures (Timed Up and Go (TUG), Berg Balance Scale (BBS), and 10-Meter Walk Test (10MWT).
Associations between trunk muscle metrics and performance were explored with regression modeling, while considering covariates known to impact performance after amputation. Average ultrasound-obtained, lumbar multifidi activity was 14 percent and 16 percent for transfemoral- and transtibial-level amputations, respectively, while extensor endurance was 37.34 and 12.61 seconds, respectively.
For TUG, the sound-side multifidi muscle activity and an interaction term explained 9.4 percent and 6.2 percent of the total variance, respectively. For 10MWT, beyond covariates, the sound-side multifidi activity and the interaction term explained 6.1 percent and 5.8 percent of the total variance, respectively.
For TUG, extensor endurance and an interaction term explained 11.9 percent and 8.3 percent of the total variance beyond covariates. For BBS and 10mWT, extensor endurance explained 11.2 percent and 17.2 percent of the total variance, respectively.
According to the study, the findings highlight deficits in lumbar multifidi activity and extensor muscle endurance among sedentary adults with a lower-limb amputation, and reduced muscle activity and endurance may be important factors to target during rehabilitation to enhance mobility-related outcomes.
The study, “Adults with lower-limb amputation: Reduced multifidi muscle activity and extensor muscle endurance is associated with worse physical performance,” was published in Clinical Physiology and Functional Imaging.