The Effects of Dual Task and Adding Weight on Lower Leg on the Stepping Ability for Fallers and Non-Fallers

目的：本實驗的首要目的乃在觀察雙重作業與下肢載重對正常老年人與曾經有過跌倒經驗的老年人跨步能力的影響，此外，本研究還想檢視，方向的改變是否會影響老年人的跨步參數。方法：本研究選取了11位健康老年人和11位有跌倒經驗之老年人，以其正常跨步速度分別往前、側、後三方向做連續3次跨步的動作，認知測驗為連續倒算數學。下肢載重指的是在慣用下肢加上1.5磅的沙包。實驗狀況包括單一作業、雙重作業、單一載重作業與雙重載重作業四種情況。統計方法將使用重複測量變異數分析來分析步長、步寬、步態時間參數與其變異度。結果：雙重作業減少了跨步的長度，但明顯增加了跨步的時間（站立期與擺盪期）與其變異度（站立期與擺盪）。不管有沒有在下肢加重，跌倒者在雙重作業情況下都會明顯增加站立期時間，但一般老人在雙重作業情況下加了重量在下肢則會使站立時問縮短。至於在方向方面，老人們會在向後跨步時會增加跨步的寬度以及其變異度，至於時間參數則在向後跨步時會縮短。結論：雙重作業明顯地改變了受試者的跨步能力，尤其是時間方面的參數。有跌倒經驗的老人相較於一般老人，使用不同的方法來應付下肢加上重量與方向改變的挑戰，尤其用改變時間參數的方法應對。但是當老人在做這些調整時，可能會影響其平衡控制的能力，臨床人員應該特別關注這些改變，以預防跌倒的發生。

關鍵字

雙重作業；跌倒者；跨步能力

並列摘要

Purposes: The purpose of this study was to explore whether dual task and an externally applied weight would affect the stepping ability in a group of healthy old adults and a group of old adults with fall experiences. Moreover, whether movement direction would affect the stepping parameter was also investigated. Methods: Eleven older adults and 11 elderly fallers were recruited from the Tainan area. A dual task paradigm (motor and cognitive tasks) was used in the current study. For the motor task, all participants were asked to perform three times of anterior, lateral, and posterior stepping tasks using their normal walking speed. Cognitive task was backward counting by 7. A sandbag weighted 1.5 lb was used to be the loading for the dominant lower leg. There were four experimental conditions including: single task, dual task, single task with weight, and dual task with weight. Four-way ANOVA with repeated measures was used for data analysis. Results: From single to dual task, subjects decreased their step length, but increased their stance time, stance time variability, swing time, and swing time variability. Fallers increased their stance time from single to dual task condition no matter they had weight on leg or not. However non-fallers decreased their stance time under the dual task condition when they had weight on their leg. For the direction effect, stepping to the posterior direction significantly increased step width and its variability, but most temporal parameters decreased in this direction. Conclusion: Dual task significantly affected the stepping ability of the subjects, especially for the temporal parameters. Fallers used different coping strategy as compared to non-fallers when they have to carry weight or move into different directions under the dual task condition, especially changing the temporal parameters. However, when they adjusted these parameters, balance control might be affected and fall risk might increase, which needs clinicians' special care.

並列關鍵字

Dual task ； Fallers ； Stepping ability

國際替代計量

The Effects of Dual Task and Adding Weight on Lower Leg on the Stepping Ability for Fallers and Non-Fallers

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