背景與目的：維持坐姿對於腦性麻痺兒童執行手部前伸動作而言，是不可或缺的輔助因素。雖然過去許多研究指出改變座椅面傾斜可以有效地增加姿勢穩定度及促進上肢動作像是手部前伸，但最適當的座椅面傾斜方向及角度仍然充滿爭議。本篇研究目的在探討以自選速度下手部前伸動作時不同座椅面傾斜對腦性麻痺兒童姿勢穩定及前伸動作效率影響。方法：共選取10位（6男，4女，7.8 ± 1.48歲）腦性麻痺兒童，以及16位（8男，8女，8.85 ± 1.89歲）正常發展兒童。每位受試者首先接受基本生理測量及兒童伸手測試。受試者坐在與膝同高椅面聽到聲音指示後手部用自選速度前伸至距離手長140%遠之目標物（按鈕），隨機安排水平、前傾及後傾座椅面，再隨機變化角度（5 o, 10 o 和 15 o)。依變相包括最大垂直地面反作用力、壓力中心前後及左右位移路徑及搖晃比例、反應及動作時間、下肢姿勢性肌肉的收縮形式。多重比較二因子變異數分析分別比較組別及座椅面傾斜方向，組別及座椅面傾斜角度的主要效果及交互作用。肌電圖流資料使用描述性統計概之。結果：在所有座椅面下，腦性麻痺兒童姿勢穩定及前伸效率相較於正常發展兒童差，但在前傾座椅面時，腦性麻痺兒童下肢承重增加使前伸時有較好姿勢穩定（壓力中心移動以前後方向為主，減少左右方向移動）。此外，在前傾座椅面下之手部前伸的反應時間及動作時間都相較於後傾座椅面短。下肢姿勢肌肉收縮變異性大，但前傾座椅面可誘發出比較一致性地背側肌肉收縮。結論：前傾座椅面使腦性麻痺兒童手部前伸過程中增加下肢承重並有較好姿勢穩定。前傾座椅面對手部前伸效率增加。臨床意義：本篇研究可作為姿勢控制缺失兒童特殊座椅面設計參考及臨床訓練依據。

Background and Purpose: Seated reaching is critical for upper extremity movement in carrying out daily living activities in children with cerebral palsy (CP). Several studies have concluded that the seat surface inclination is an important factor to improve postural stability during functional movement, such as reaching. However, the optimal seat surface inclination is still disputed. The purpose of the study was to examine the effects of seat surface inclination on postural stability and reaching efficiency during a self-paced forward reaching in children with and without CP. Methods: Ten children (6 boys, 4 girls; aged: 7.8 ± 1.48 years) with CP and sixteen children (8 boys and 8 girls; aged: 8.85 ± 1.89 years) without CP were recruited. Each child first received physical examination and pediatric reach test. During a trial, a child was asked to be seated and press a switch at a distance of 140% arm length distance at listening a verbal cue. A flat seat surface and three degrees (5 o, 10 o and 15 o) of inclination in two directions seat surface conditions were randomly assigned. Center of pressure variables derived from ground reaction force, EMG data of lower extremities, reaction time and movement time were collected and used as dependent variables. Two-way ANOVA with repeated measure was used to compare the effects of group, inclination direction, degrees and their interaction. EMG data were analyzed descriptively. Results: The results showed that the children with CP presented more postural instability and reaching inefficiency than children without CP in all test conditions. But the children with CP showed more weight bearing of lower extremities and better postural stability (more straight forward movement of COP and less medial-lateral movement of COP) during reaching in anterior inclined seat surface. Moreover, the reaction time and movement time were shorter in the anterior inclined than in the posterior inclined seat surface conditions. The patterns of muscle activation were variable, but the dorsal side muscles demonstrated more consistently patterns than the anterior side, especially during an anterior inclined seat surface test condition. Conclusions: The anterior inclined seat surface may allow children with CP to increase the contribution of the lower extremities for weight bearing and show better postural stability during a forward reaching. The reaction time and movement of arm reaching are also shorter in the anterior inclined seat surface conditions. Clinical Relevance: Findings may be used as reference for seat design and rehabilitation training for children with postural control difficulties.

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