平板電腦可望成為下一世代新的電腦資訊產品，其對原本的產業生態、消費者使用習慣與人機互動方式帶來新的改變。除此之外，平板電腦雖然具有方便與可攜性的特色，但它可能帶來與健康相關方面不良的邊際效應問題是值得關注的議題。但在人因工程方面的研究，對於新型平板電腦的設計概念可能對使用者造成的健康相關效應認知仍然不足，需要更多實驗性研究資料來佐證。另外，在多項消費者市場調查結果指出，平板電腦遭受最多使用者批評的就是在文字輸入作業上的不便利性，而是否可經由人機介面的改善解決此問題呢?
因此，本研究目的在於以人因工程的角度，探討使用者在常見的使用姿勢(標準打字姿勢與床墊作業姿勢)與平板電腦的人機互動情形。同時，針對虛擬鍵盤進行不同的介面配置設計(標準、寬間距式與人因分離式鍵盤)，以評估是否可以經由改善虛擬鍵盤的介面排列方式，來提升產品的使用性同時降低使用者肌肉骨骼系統的負擔。除了透過易用性評估量表與肌肉疲勞自覺量表外，經由自行開發的應用軟體程式進行易用性分析，並透過肌電圖量測屈指淺肌、伸指肌、頸豎脊肌、上斜方肌與胸鎖乳突肌，同時，也利用電子量角器測量手腕、手肘及頸部的角度，作進一步的量化分析。
研究結果顯示，虛擬鍵盤的介面配置，對於易用性指標、肌電圖與手腕尺/橈偏角度有顯著性的影響，整體而言，使用人因分離式鍵盤，其打字績效表現較佳，手腕尺/橈偏角度也最接近正中姿勢。此外，使用床墊姿勢手腕伸展的角度明顯高出標準姿勢許多，兩者間的角度差距超過20度。再者，使用標準打字姿勢，頸豎脊肌與上斜方肌的負荷比床墊姿勢還大。另外，性別之間肌肉負荷強度也有所不同，研究結果顯示，女生在屈指淺肌、上斜方肌及胸鎖乳突肌的負荷強度都比男生還高，同樣地，相較之下女生手腕尺偏角度及活動度(ROM)也比男生高。除此此外，發現使用者長時間打字時，在易用性指標及電子量角器測量的指標上也有顯著性的變化。

Tablet PC is expected to become the next generation of new computer and information technology products. Its prevalence brings new changes to industrial ecology, consumer habits and human-computer interaction. The convenience and portability popularized by Tablet PC, however, may cause potential health-related problems. Moreover, it has been showed in several consumer market surveys that the current generations of Tablet PC trends to produce unpleasant user experiences during conventional typing activities.
Therefore, the purpose of this study is to explore the interaction between user and Tablet PC during text-entry tasks while assumed two common postures (standard posture and bed-sitting posture). Three different types of the interface design for virtual keyboard (standard, wide-spacing, split style) were evaluated with respect to the usability and physical burdens on users' musculoskeletal system. Typing performance matrices and self-perceived evaluations were recorded, along with electromyographic signals from flexor digitorum superficialis(FDS), extensor digitorum communis(EDC), cervical erector spinae(CES), upper trapezius(UT) and sternocleidomastoid(SCM). On the same time, the variation of upper-limb body joints during the experiment were simultaneously measured in aid of comprehensive evaluation.
The results showed that the virtual keyboard design has significant impacts on muscular activities and wrist posture. Overall, split keyboard is better in terms of typing performance and the resulting wrist radial/ulnar deviation is closet to neutral posture. Furthermore, when using the bed-sitting posture the wrist extension was significantly higher than that of standard posture by more than 20 degrees. On the contrary, the physical load experienced in CES and UT larger in standard posture, females tend to have higher exertion in the FDS, UT and SCM and prone to deviate their wrists to the ulnar side.

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