老年人與年輕人於無預警步態終止時之生物力學分析

老人跌倒是一個嚴重的醫療及社會問題，且是造成老人受傷甚至死亡重要的原因。文獻指出，有百分之五十的老人跌倒是發生在日常活動中，且在做動作的轉換(例如步態開始或結束、跨越障礙物等等)時更會增加跌倒的風險，因此，本研究目的在於探討老年人與年輕人在無預警步態終止時身體的平衡控制能力，利用配備有七台紅外線超高頻攝影機之動作分析系統及兩塊測力板，收取受試者運動學及力動學等資料，以了解老化造成控制能力下降的原因。研究結果得知，老年人在無預警步態終止時需要的反應時間較長，無法在無預警步態終止時立即停止步態，且老年人的向前COM分量略大於年輕人，需要較多的反應時間將COM向後拉回以保持穩定。另一方面，老年人在踏上力板後前腳的向後煞車力較年輕人小，且在前後方向的COM-COP差值較年輕人大，此現象為了補償煞車力的不足，將COM的位置向後拉回維持在身體較後面的位置，以增加全身的平衡。關節角度及力矩變化方面，老年人的髖關節及膝關節的屈曲角度在不同步頻下均大於年輕人，因為老年人在無預警步態終止時增加髖關節及膝關節屈曲角度，採用降低COM垂直位置的策略以保持平衡，顯示老年人藉由改變關節角度來增加步態終止時的平衡穩定性。隨著年齡增加，身體老化造成全身協調能力下降，是造成老年族群發生事故的重要因素，藉由分析步態終止時的老年人的平衡穩定情形，便能了解並提供預防老人在步態終止時跌倒的最佳策略。

關鍵字

步態終止；運動學；力動學；老化；質量中心

並列摘要

Falling in the elderly is a serious medical and social problem and it is a vital reason that causes death in the elderly. From the literature review, 50% of falling happened in daily activities especially when gait transition such as gait initiation, termination, obstacle crossing and so on. In the present study, older and young healthy adults were recruited to investigate the control of gait stability due to aging with motion analysis techniques. Compared to the baseline data in the young group, the elderly had greater AP COM displacement and needed longer reaction time to achieve stable gait termination. On the other hand, the elderly had smaller AP braking force in the leading limb and greater COM-COP separation. This result could be the compensation for the reduced braking force which would lead to instability or falling during gait termination. The elderly also had greater hip and knee flexion angle in different cadences. This was because the elderly had lower COM vertical position to achieve gait termination. Therefore, they used different strategy to complete gait termination. To understand the control of gait stability, the results of biomechanical analysis in every aspect could provide sufficient information of effective gait termination strategies in the elderly.

並列關鍵字

gait termination ； kinematics ； kinetics ； aging ； center of mass

參考文獻

Allander, E., O. J. Bjornsson, et al. (1974). "Normal range of joint movements in shoulder, hip, wrist and thumb with special reference to side: a comparison between two populations." International Journal of Epidemiology 3(3): 253-261.

Bishop, M., D. Brunt, et al. (2004). "The effect of velocity on the strategies used during gait termination." Gait and Posture 20(2): 134-139.

Campbell, A. J., M. J. Borrie, et al. (1989). "Risk factors for falls in a community-based prospective study of people 70 years and older." Journal of gerontology 44(5): M112.

Campbell, A. J., M. J. Borrie, et al. (1990). "Circumstances and consequences of falls experienced by a community population 70 years and over during a prospective study." Age and Ageing 19(2): 136-141.

Den Otter, A., A. Geurts, et al. (2004). "Speed related changes in muscle activity from normal to very slow walking speeds." Gait & Posture 19(3): 270-278.

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老年人與年輕人於無預警步態終止時之生物力學分析

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