이중과제 상황에서 연령에 따른 자세조절 전략의 차이와 하지근력의 역할

다국어 초록 (Multilingual Abstract)

This study aimed to compare age-related differences in postural control responses under single-task and dual-task conditions and to identify factors explaining dual-task postural control patterns.
A total of 22 young adults and 22 older adults participated in this study. Participants performed single-task standing, visual dual-task standing, and auditory dual-task standing conditions on force plates. Postural control was assessed using linear, frequency-domain, and nonlinear variables derived from center of pressure（CoP） data. Postural dual-task costs（DTCs） were calculated relative to the single-task standing condition. Mixed repeated-measures ANCOVA was used to examine the effects of age group, task condition, and their interaction on postural control variables and DTCs. Following the interaction analysis, hierarchical multiple regression analyses examined whether knee extension strength and global cognitive function assessed using the K-MoCA explained MV_ML DTC. Exploratory age-group-specific regression and mediation analyses were additionally performed.
Older adults showed higher RMS_AP, RMS_ML, MV_AP, and CEA values and lower mediolateral frequency and complexity measures than young adults. Under dual-task conditions, RMS_AP and CEA decreased compared with the single-task condition, and no significant difference was observed between visual and auditory dual-task conditions. A significant age group × task condition interaction was found only for mediolateral mean velocity（MV_ML）. MV_ML decreased in young adults but increased in older adults under dual-task conditions, resulting in negative MV_ML DTC values in young adults and positive values in older adults.
In the hierarchical regression analyses, knee extension strength significantly predicted MV_ML DTC in the auditory dual-task condition, whereas global cognitive function assessed using the K-MoCA did not. Exploratory analyses showed that the relationship between knee extension strength and MV_ML DTC was significant only in older adults, and that the association between age group and auditory MV_ML DTC involved an indirect pathway via knee extension strength.
These findings suggest that age-related differences in dual-task postural control are not limited to overall postural sway but may also appear as distinct response patterns in mediolateral CoP velocity control. In particular, auditory MV_ML DTC was more closely associated with knee extension strength than with global cognitive function, suggesting that lower-extremity functional resources may contribute to postural control under dual-task conditions in older adults.

목차 (Table of Contents)

• I. 서론 1
• 1. 연구의 필요성 1
• 2. 연구의 목적 4
• 3. 연구의 가설 5
• 4. 용어의 정의 5
• II. 이론적 배경 7
• 1. 자세조절과 노화 7
• 2. CoP 기반 자세조절 평가 10
• 3. 이중과제와 자세조절 12
• 4. 이중과제 비용의 개인차 요인 15
• III. 연구 방법 18
• 1. 연구 참여자 18
• 2. 측정 도구 및 장비 20
• 3. 실험 과제 및 조건 24
• 4. 실험 절차 25
• 5. 자료 처리 및 통계 분석 28
• IV. 연구 결과 33
• 1. 연구 참여자 특성 33
• 2. 인지과제 수행 결과 34
• 3. 자세조절 지표의 집단 및 조건 간 차이 34
• 4. 이중과제 비용（DTC） 39
• 5. 이중과제 비용의 설명 요인 40
• V. 논의 44
• 1. 노화에 따른 자세조절 특성 44
• 2. 이중과제가 자세조절에 미치는 영향 46
• 3. 이중과제에 대한 연령별 자세조절 반응 패턴 47
• 4. 이중과제 비용의 설명 요인 51
• 5. 연구의 의의 및 제한점 54
• VI. 결론 57
• 참고문헌 59
• Abstract 74