跌倒是老人或中風病患常見的傷害之一，也是老年人事故的死因之一，其可能導致老人或中風病患的獨立活動功能喪失，進一步加速身體功能的退化，帶來家庭與社會的龐大支出。故本研究旨在觀察不同族群(健康年輕人、健康老人、中風患者)站立前伸觸壓按鈕的變異，利用距離的增加，觀察人體接近失去平衡的過程中，相關之生物力學變數，並找出可能造成跌倒的相關因子。本實驗招收健康年輕人、健康老人和中風病患，利用三維動作捕捉系統、無線肌電儀和六軸測力板，讓受測者進行站立前伸的動作。由簡單的穩定極限之動作控制為基準，發現年輕人比老年人可以摸得更遠，除了身體本身肌肉的延展外，還加上了踝關節的策略，從肌肉的活化程度，年輕人會用較多的腓腸肌（Gastrocnemius），而老年人和中風病患皆在股二頭肌（Biceps femoris）上有較顯著的表現，在COP的移動軌跡方面，老年人與中風患者都有明顯向斜前方移動的表現，導致臀中肌(Gluteal medium)須要使用較多的力量，而年輕人的足底壓力軌跡都是向前的部分比較多，老人則是兩側移動，推估可能也是老人容易跌倒的重點之一。此研究結果日後回饋於臨床訓練人員，希望能夠藉由訓練病患應付正常生活常見之站立前伸動作，降低老人或中風患者的跌倒機率。

Fall is one of the most common leading causes to accelerate the degradation of physical function especially in the elderly and in the patients with stroke. Current study aimed to investigate the postural control and biomechanical strategies during standing reaching in healthy young controls, the elderly and patients with stroke. Subjects in each of the healthy controls, the elderly, and stroke group were recruited. Three-dimensional motion capture system, wireless electromyography system and force plates were used to collect motion data during standing reaching with difference distance until limit of stability. Objective biomechanical indices, namely joint angles and moments at hip, knee, and ankle as well as ground reaction force and electromyography variables during reaching tasks were calculated and compared between conditions and between groups. It was found that the young controls were able to reach further than the elderly, not only using the extensor of the trunk, but also using the ankle strategy. From the measurement of muscle activation, we found that the young subject used more gastrocnemius, while the elderly and the patients with stroke used more biceps femoris. In terms of center of pressure movement trajectory, the movement trajectory of the young people shift more anteriorly. Study design of forward reaching was established with preliminary results. Continuing study with more profound analysis is warranted to identify related factors which may cause loss of stability and falls and to provide more insight for the prevention of falls.

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