中風患者需要經過一段漫長的治療以及復健過程，才能夠達到用兩腳站立並 保持穩定的動作。然而僅就力板所測得之壓力中心 (Center of Pressure, COP) 參數 來反應姿勢控制的能力仍有不足之處，所以本研究的目的是透過壓力中心與重心 (Center of Mass, COM) 的相對距離及COP 安全幅度，來重新檢視中風患者與健康 成人，在雙腳靜態站立時，姿勢穩定上的差異。共計20 位健康成人與20 位中風 患者參與實驗。受測者身體表面上會貼上反光球以便數據化身體各肢段的位置， 並赤腳踩在力板上靜止不動站立30 秒鐘。研究者會同步收集運動學、測力板資料， 並分別計算出COM、COP 等參數。研究結果顯示單就力板讀數而言，中風患者不 論在前後、左右方向，COP 位移幅度與晃動軌跡皆出現較差的表現。但若加入重 心移動的考量，則可發現中風患者在前後方向的穩定表現，確實遠不如健康成人， 而在左右穩定上卻出現無明顯的差異。此外，中風患者會出現類似馬蹄足 (pes equinus) 站姿，COP 安全幅度是明顯較小，且位置向前移偏靠近腳趾邊緣，而健 康成人則約落於腳掌之中間範圍。導致此COP 前移的原因可能與中風患者小腿後 部肌群的過高張力有關。臨床治療師在面對小腿三頭肌有明顯痙攣張力的中風病 患，在訓練靜態站立平衡前，可透過肌肉張力放鬆的手法，來增大COP 安全幅度。

Stroke patients have gone through a long process of rehabilitation to be able to stand with two feet and maintain postural stability. However, the parameters with regard to the center of pressure (COP) derived from force platform are not sufficient for determining the ability of postural control. Therefore, the purpose of this study is to reevaluate the postural stabilityduring quiet standing in stroke patients and healthy adults through the biomechanical variable COP-COM, which represents the distance between the COP and COM, and saftey margin of COP. Twenty stroke patients and twenty healthy adults participated in this study. Reflective markers were acttached on the subject’s body to indentify the position of each body segment. Subjects were asked to perform a quiet standing with bare feet on the force plate for 30 seconds. Researcher collected the kinematic and kinetic variables synchronously, and after that calculated the COM and COP parameters respectively. The results indicated that stroke patients displayed worse postural stability in anterior-posterior and the medial-lateral directions than did the healthy adults if only the reading from the force plate was inspected. However, if adding consideration of the COM, stroke patients did show poor postural stability in anterior-posterior direction, but have no significant differences in medial-lateral directions. Furthermore, stroke patients showed pes equinus during standing with small saftey margin of COP. The COP was obviously moved forward along the edge of toes. On the other hand, the COP in healthy adults was located near in the middle of the feet. The possible reason shifting the COP forward may be related to the spasticity of triceps surae in stroke patients. Clinical therapists should be done the calf muscle relaxation techniques prior to balance training in stroke patients who has severe spasticity of triceps surae.