老年人下楼梯下肢关节做功模式分析

Analysis on Mechanical Work Patterns of Lower Extremity Joints in Older Adults During Stair Descent

目的探究下楼梯行走过程中老龄化对老年人下肢关节做功模式的影响,丰富楼梯行走的防跌倒理论。方法采用Vicon红外运动捕捉系统和Kistler三维测力台同步采集青年人和老年人下楼梯行走的运动学和动力学数据,利用下肢关节角度、力矩、功率、做功贡献度指标对下肢关节做功模式进行量化评定。结果下楼梯过程中,青年组和老年组下肢三关节角度、力矩、功率的变化趋势一致。在优势腿的1个支撑相内,老年人的屈髋力矩峰值、伸膝力矩第1峰值、第2峰值、跖屈力矩第1峰值、膝负功率第1峰值、第2峰值、踝负功率峰值以及髋、膝、踝关节净功均显著降低(P<0.05);伸髋力矩峰值、髋负功率峰值、踝关节做功贡献度显著增加(P<0.05),髋、膝关节做功贡献度并未出现显著性差异(P>0.05)。结论在下楼梯过程中,老年人下肢关节力学特征显著降低。老年人采取不同于青年人的下肢关节做功模式。老年人通过较大的伸髋姿势抵制躯干的过度前倾,同时采取踝关节做功的代偿模式,提高下楼梯行走的身体稳定性。建议老年人在锻炼时应以增加膝、踝关节肌肉力量的项目为主,以维持下楼梯的姿势控制能力。

Objective To investigate the effect of aging on mechanical work patterns of lower extremity joints in older adults during stair descent,so as to enrich the fall-prevention theory of stair walking.Methods Vicon infrared motion capture system and Kistler platform were synchronized to collect the kinematic and kinetic data.The mechanical work was quantified by using parameters such as joint angle,moment,power,and mechanical work contribution of lower joints.Results Older adults demonstrated a consistent trend in joint angle,moment and power of lower limbs with young adults during stair descent.Compared with young adults,older adults showed decreased peak hip flexion moment,the first peak and second peak of knee extension moment,the first peak of ankle plantarflexion moment,the first and second peak peak of knee negative power,peak ankle 1010 negative power,net mechanical work of hip,knee,and ankle joints(P<0.05).Significantl increase was found in peak hip extension moment,peak hip negative s power,and the mechanical work contribution of ankle joint among older adults(P<0.05).There was no significant difference in mechanical work of hip and knee joints between two groups(P>0.05).Conclusions The mechanical characteristics of lower extremity joints in older adults were significantly reduced during stair descent.Older adults adopted a strategy in mechanical work which was different from young adults.They would increase hip extension to resist the excessive trunk leaning forward,together with the mechanical work of ankle joint as the compensatory mode,so as to improve body stability during stair decent.It is suggested that older adults should mainly increase the strength of knee and ankle muscles during exercise to retain the postural stability during stair descent.