老年人步行策略與下肢能量流動的型態

Abstract

本研究的目的是利用能量的觀點來檢視在步行時人體的控制策略與能量分布，並比較老年人與年輕人在步行時能量分布型態的不同。進一步分析下肢能量的協調性與因老化而產生的代償作用對步態的影響。 利用主成分分析法與能量流的概念，來達到簡化變數的目的。研究結果顯示，老年人有較低的踝關節能量(Ankle power)，並同時有膝關節與髖關節的關節能量提高(knee and Hip power)，此一現象表示老年人運用較多的近端肌肉來達到代償的目的。然而此種代償作用，是由於下肢能量分布不均的結果。大腿肢段機械能變化與分布明顯的不同於年輕受試者，造成髖關節與膝關節肌肉必須去調適這樣的代償作用，因此形成與年輕人截然不同的能量流動型態。 總結而言，老年人因踝關節肌力下降的原因，造成其他關節的代償作用，會改變整體的步態表現，其中又以髖關節為最明顯，這樣的表徵也許表露出老年人在步行時的策略會朝向比較安全的方式而不是達到比較快的速度。

Objective: The aim of this study is to investigate lower limb energy transfer, changes in joint coordination and compensation that elders adopt due to aging. Design: Experimental, principal component analysis (PCA) and mechanical energy model Participants: 11 healthy young adults and 11 healthy elders Setting: Rehabilitation Engineering Research Center with instrumented gait laboratory. Main outcome measures: Temporal-spatial parameters and kinematic and kinetic parameters including joint angles, joint moment, joint power and segmental power were calculated. Results: Elder subjects showed reduced peak ankle power generation, more knee power ab-sorption and more hip flexor power as compared to young subjects. It indicates that weak plantar-flexors in the elder population generate lesser power for locomotion .While at fast speed, elders generate more hip concentric power than at self-selected speed reveals a hip strategy they adopt. Conclusion: Decreased ankle power in elders induces compensation of other muscular. It results in energy distributing abnormally thus evokes hip flexor and knee extensor simultaneously act to balance energy on lower extremity. Lower thigh segment energy due to insuffi-cient ankle power also need more hip flexor power for larger stride length. Elders also produced lesser power from transverse and frontal plane it potentially indicates more instable in gait.