Comparison of the Lower Extremity Kinematics and Center of Mass Variations in Sit-to-Stand and Stand-to-Sit Movements of Older Fallers and Nonfallers

OBJECTIVE: To compare the differences in sit-to-stand and stand-to-sit movements of older nonfalling males and older male fallers (also referred to herein as fallers) to contribute to the development of posture transfer–assisting devices or interventional therapies to prevent falls. DESIGN: Controlled study. SETTING: University research laboratory. PARTICIPANTS: Ten older men (mean age, 75.9±5.4 years) who had fallen or been unstable at least once in the past year and 10 nonfalling older men (mean age, 70.0±5.0 years) participated in this study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Movement duration; sagittal trunk, hip, knee, and ankle joint range of motion (ROM); anteroposterior and mediolateral (ML) center of mass (COM) total trajectory. RESULTS: During the sit-to-stand transition, fallers exhibited greater trunk joint ROM in the flexion and extension phase and smaller hip joint ROM in the extension phase as well as greater ML COM total trajectory. During stand-to-sit, older fallers exhibited greater trunk joint ROM in the flexion phase and smaller hip and knee joint ROM in the flexion phase as well as greater ML COM total trajectory. Older fallers took more time to perform the stand-to-sit and had greater ML COM total trajectory during the movement; additionally, they exhibited different proportional distributions of ROM for each joint compared with nonfaller. CONCLUSION: Older fallers had more difficulty performing stand-to-sit than sit-to-stand; they exhibited more body sway in COM motion and, in particular, were unable to control ML motion y. Older fallers were more likely to adopt trunk, hip, and knee joint flexion strategies to maintain balance during sit-to-stand and stand-to-sit than nonfaller participants were.