老龄化对下楼梯动态稳定性及髌股关节力学特征的影响

目的:比较青年和老年女性下楼梯行走中动态稳定性及髌股关节力学特征的差异,探讨老龄化对下楼梯行走跌倒风险的影响。方法:选取青年和老年女性受试者各18名,采用Vicon红外运动捕捉系统、Kistler三维测力台同步采集受试者下楼梯行走的运动学和动力学数据,通过动态稳度(MoS)和髌股关节应力(PFJS)等指标分别对受试者下楼梯行走的动态稳定性和髌股关节受力特征进行量化评定。结果:在摆动腿触地时刻,左-右方向青年组与老年组的MoS无显著性差异(P=0.18),前-后方向老年组的MoS较小(P=0.000),且为负值。两组受试者的膝关节角度、矢状面膝关节力矩(KM)、股四头肌肌力(QF)、PFJS的曲线图变化趋势一致,且在单支撑相时间内均出现两个峰值。与青年组相比,老年组的KM第一峰值(P=0.014)、KM的第二峰值(P=0.000)、QF的第一峰值(P=0.001)、QF的第二峰值(P=0.000)、PFJS的第一峰值(P=0.012)和PFJS的第二峰值(P=0.022)均较小。结论:老年女性在下楼梯行走中向前跌倒的风险较大,PFJS较小。老年人可能采取减小QF、KM,降低PFJS的神经...

The Influence of Aging on Dynamic Stability and Mechanical Characteristics of Petellofemoral Joint when Walking Downstairs

Objective To explore the influence of aging on the risk of falls by comparing the differ⁃ence in dynamic stability and mechanical characteristics of the patellofemoral joint when walking down⁃stairs between the elderly and youth females.Methods A total of 18 youth and elderly females were re⁃cruited respectively,and collected the data of their kinematics and kinetics when walking downstairs using the Vicon infrared motion capture system and kistler three-dimentional force platform.The mar⁃gin of stability(MoS)and patellofemoral joint stress(PFJS)were used to assess the dynamic stability and mechanical characteristics of the patellofemoral joint.Results At the moment of right heel striking the ground,no significant differences(P=0.18)were found in the average mediolateral MoS between the two groups.However,the average anteroposterior MoS of the elderly group was of a negative val⁃ue,significantly lower than the youth group(P=0.000).Both groups showed the same trend in curves of the average knee joint angle,sagittle plane knee joint moment(KM)and quadriceps force(QF),with two peak values appearing at the single-support phase.Compared with the youth group,the first and second peak values of KM(P=0.014),QF(P=0.001),and PFJS(P=0.012)of the elderly group were significantly smaller.Conclusions The elderly females are of greater risk of falling forward while walking downstairs,with smaller PFJS value.The elderly females might decrease the neuromuscular self-protection mechanism of PFJS by lowering QF and KM,which will reduce their stability when walking downstairs.Therefore,it is recommended to enhance their force of the knee extensor.Mean⁃while,the elderly should decrease the risk of falling forward by shifting the center of mass backward appropriately and increasing the step length.