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Vector coding analysis of coordinated joint movement during sit-to-stand: (Bachelor thesis)

Μπαλή, Παρασκευή/ Bali, Paraskevi

Falls constitute a major public health problem in the elderly population, with 28-35% of individuals over 65 years experiencing at least one fall annually. Sit-to-stand represents a fundamental daily activity performed approximately 60 times per day, and difficulty in its execution is directly associated with increased fall risk. Despite extensive research on biomechanical parameters, there is limited knowledge regarding joint synergy patterns used by older adults with different fall risks. The purpose of this study was to apply vector coding methodology for the analysis of inter-joint synergy patterns during sit-to-stand in older adults with low and high fall risk. Seventy older adults (65-87 years) participated, categorized into high (n=36) and low risk groups (n=34) based on the Hopkins Fall Risk Assessment scale. Kinematic analysis was performed using Vicon system and Needham's vector coding method was applied for hip-knee and knee-ankle synergy analysis. Hip-knee synergy showed similar patterns between groups (50% vs 54% in-phase dominance). Knee-ankle synergy differed: the high-risk group exhibited 81% in-phase patterns versus 64% in the low-risk group, possibly as an adaptive strategy related to fear of falling. Findings indicate that motor control adaptations occur primarily in peripheral joints, supporting the integration of vector coding in clinical assessment protocols.