Persons with unilateral transfemoral amputation have altered lumbosacral kinetics during sitting and standing movements

•Joint moments and powers at L5/S1 analyzed during sitting and standing movements.•Larger peak lumbosacral kinetics found among persons with transfemoral amputation.•Minimal differences between powered and passive knees, especially when sitting down.•Altered lumbosacral kinetics suggest potential pathways for low back pain development.

Increases in spinal loading have been related to altered movements of the lower back during gait among persons with lower limb amputation, movements which are self-perceived by these individuals as contributing factors in the development of low back pain. However, the relationships between altered trunk kinematics and associated changes in lumbosacral kinetics during sit-to-stand and stand-to-sit movements in this population have not yet been assessed. Three-dimensional lumbosacral kinetics (joint moments and powers) were compared between 9 persons with unilateral transfemoral amputation (wearing both a powered and passive knee device), and 9 uninjured controls, performing five consecutive sit-to-stand and stand-to-sit movements. During sit-to-stand movements, lumbosacral joint moments and powers were significantly larger among persons with transfemoral amputation relative to uninjured controls. During stand-to-sit movements, lumbosacral joint moments and powers were also significantly larger among persons with transfemoral amputation relative to uninjured controls, with the exception of sagittal joint powers. Minimal differences in kinetic measures were noted between the powered and passive knee devices among persons with transfemoral amputation across all conditions. Altered lumbosacral kinetics during sitting and standing movements, important activities of daily living, may play a biomechanical role in the onset and/or recurrence of low back pain or injury among persons with lower-limb amputation.