Background: Care-needing older adults and disabled individuals often require handrails for assistance of movements, such as sit-to-stand movements. Handrails must be set at the appropriate position; however, the effects of handrail height on joint movement and center-of-gravity movements during sit-to-stand movement remain unclear. In the present study, we sought to clarify the effects of handrail height on joint movement, center-of-gravity, and floor reaction force during sit-to-stand movement.
Methods: Subjects included 16 healthy young adults and 25 older adults who require long-term care. Kinetic and kinematic measurements during sit-to-stand movement of young adults were conducted using a 3-D motion analyzer and a force plate. Trunk forward tilt angle during sit-to-stand movement of older adults was measured using a still image from a video recording.
Results: Using low handrails, sit-to-stand movement resulted in an increased hip flexion angle, ankle dorsiflexion angle, and trunk forward tilt angle and a greater forward center-of-gravity shift than when not using handrails in young adults during seat-off. In contrast, using high handrails resulted in a smaller hip flexion angle and trunk forward tilt angle in young adults. The backward force on the floor was decreased in the low handrail condition, and was increased in the high handrail condition rather than that of sit-to-stand movement without handrails in young adults. The effect of handrail height on trunk forward tilt angle was the same in both healthy young adults and care-needing older adults during seat-off.
Conclusion: Because handrail height affects joint movement and shift in the center-of-gravity during sit-to-stand movement, handrail position should be selected to match the status of older adults with functional impairment.