老年人跨越不同高度障礙物之生物力學分析

Biomechanical Analysis of Stepping Over Obstacles of Different Heights in The Elderly

邱顯光(Hsien-Kuang Chiu)

指導教授 ： 劉錦璋

國立臺灣師範大學/運動與休閒學院/體育學系/碩士(2004年)

摘要

在步態中跨越障礙物以及較差的身體平衡感，是最常引起老人跌倒的兩個因素。本研究目的在探討老人步行時跨越不同高度障礙物動作，對步態重心平衡及下肢神經肌肉調控的影響。實驗受試者為各10位健康年輕人(平均年齡20.9±1.73)與健康老年人(平均年齡73.5±4.06)。實驗要求受試者自我配速行走約六公尺後，跨越不同高度之障礙物；本實驗的障礙高度分為四個層級，即無高度、低高度(5公分)、中高度(20公分)與高高度(35公分)。利用一塊測力板(1200Hz)、一台Redlake高速攝影機(60Hz)和Biovision肌電圖儀器(1200Hz)等，進行各項參數收集。以混合設計二因子變異數分析檢定四種高度與兩組受試者之各項力學參數差異顯著性，統計水準定為α = .05。經分析後主要的研究結果為：
一、在跨越較高障礙物的單腳支撐期間，受試者增加重心垂直移動、減少向前重心線動量，並在身體重心與壓力中心平衡穩定的限度內，增加重心與壓力中心間距(p<.05)，使身體通過障礙物。
二、在跨越較高障礙高度時，受試者在單腳支撐期因跨越動作改變致使下肢肌肉收縮順序有所改變；此外，老年人在擺動期對股直肌與腓腸肌有較高肌肉活化需求之傾向。
三、老年人跨越漸增障礙高度時，有其獨特的跨越策略：(1)縮短步幅長度並增加垂直位移，(2)減少向前重心線動量(p<.01)，(3)增加跟隨腳跨越前足尖與障礙物距離(p<.001)，以順利通過各種障礙高度。

關鍵字

跨越障礙物 ； 步態 ； 平衡控制 ； 肌電圖

並列摘要

Stepping over obstacles and imbalance during gait are two of the most common causes of falls in the elderly. Thus, the purpose of this study was to investigate the effect of motions in negotiating obstacles of different heights on maintaining the balance of whole body’s center of mass and controlling the neuromuscular system of lower limbs in the elderly.
The subjects of this study included 10 healthy young adults (mean age = 20.9±1.73 yrs) and 10 healthy elderly (mean age = 73.5±4.06 yrs). Subjects were instructed to walk along a 6-m walkway, step over the obstacle at a self-selected speed. In this study, the heights were defined as four levels: unobstructed level walking, low height (5cm), medium height (25cm) and high height (35cm). A Redlake high-speed camera (60Hz), a Kistler force platform (1200Hz), and the Biovision EMG system (1200Hz) were used to collect the kinematic and kinetic data of the crossing stride. The selected variables were tested by 2-way ANOVA mixed design. Statistical significance was set at α=.05. According to the results analyzed, we concluded that:
(1) Stepping over the higher obstacles resulted in significantly greater ranges of motion of the center of mass (CM) in the vertical directions, decreasing the anterior CM leaner momentum, and greater anterior-posterior distance between the CM and COP (p<.05).
(2) While crossing the higher obstacle conditions, cause of changing the motion of crossing stride resulted in different sequence of muscular contraction during single support phase. Besides, the elderly existed the tendency of greater Rectus femoris and Gastrocnemius activity than young adults during the period of swinging phase.
(3) There were several different strategies between the two age groups in crossing the higher obstacle conditions: (i) the elderly decreased more step length and increased the vertical displacement than young adults, (ii) the anterior CM leaner momentum of the elderly was also less than young adults (p<.01), (iii) besides, the toe – obstacle distance of trailing limb before crossing in the elderly was greater than young adults (p<.001).

並列關鍵字

obstacle crossing ； gait ； balance control ； EMG

參考文獻

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