Sedentary behavior and lower-limb muscle strength in community-dwelling older adults:the mediating and moderating effects of fear of falling and age

Hong Jintao; Wang Jingjing; Li Yansong; Wang Chen; Mi Shouling

doi:10.12307/2025.662

Abstract：BACKGROUND:The lower-limb muscle strength shows a significant physiological decline with aging.There may be a certain correlation between sedentary behavior,fear of falling,age and lower-limb muscle strength,but the influence path and effect relationship among them are not yet clear. OBJECTIVE:To examine the relationship between sedentary behavior and lower-limb muscle strength,and to explore the influences of fear of falling and age in such an association among community-dwelling older adults. METHODS:This cross-sectional study recruited 331 community-dwelling older adults(aged≥60 years)in Shanghai.A questionnaire survey was conducted to collect basic information,demographic data,etc.The Short Form of the International Physical Activity Questionnaire was applied to measure sedentary time.Lower-limb muscle strength was assessed by the 30-second chair-stand test.Fear of falling was measured by the Chinese version of Fall Efficacy Scale-International.Descriptive statistics analysis,correlation analysis,regression-based path analysis and mediation analyses were performed on the data. RESULTS AND CONCLUSION:Valid data from 318 community-dwelling older adults[78.9%females,mean age(67.8±5.5)years old]were finally included in the analysis.There were 185 with sedentary time≥3 hours and 133 with sedentary time<3 hours.(1)There was a positive correlation between sedentary behavior and fear of falling(P<0.01),and there were negative correlations between lower-limb muscle strength and sedentary behavior(P<0.01)and between lower-limb muscle strength and fear of falling(P<0.001).(2)Sedentary behavior negatively predicted lower-limb muscle strength(β=-0.125,P<0.05),and positively predicted fear of falling(β=0.182,P<0.01).Fear of falling negatively predicted lower-limb muscle strength(β=-0.293,P<0.001).(3)Fear of falling mediated the relationship between sedentary behavior and lower-limb muscle strength(β=-0.053,95%confidence interval:-0.100 to-0.018).(4)Sedentary behavior had a statistically significant predictive effect on fear of falling(β=0.164,P<0.01),indicating that age moderates the effect of sedentary behavior on fear of falling.