背景與目的：雙數位式傾斜儀是一種測量胸椎後凸角度和胸椎活動度之非侵入式工具。本研究目的在於探討雙數位式傾斜儀於測量健康成年人胸椎後凸角度和胸廓活動度的可信度。方法：共有10位受試者參與研究，測量姿勢與動作包括胸椎後凸角度和各方向活動度。為了評估同日再測信度，前兩次測量時段是安排在同一天，之間間隔30分鐘。第二天再進行第三次測量，以評估隔天再測信度。信度的強度是以組內相關係數(intraclass correlation coefficients,ICC)、測量標準誤(standard error of measurement,SEM)及最小可偵測變化值(minimal detectable change with 95%confidence,MDC95)來做判斷。結果：以雙數位式傾斜儀測量站姿與坐姿下之胸椎後凸角度，以及屈曲、伸直、側彎和旋轉的胸椎活動度，均有良好的同天再測信度(ICC=0.87~0.99;SEM=0.7~2.9°;MDC95=1.91~8.32°)。胸椎後凸角度的隔日再測信度與屈曲，伸展和旋轉的胸椎活動度相當(ICC=0.77~0.93;SEM=1.5~3°;MDC95=4.13~8.32°)。然而，胸椎側彎的隔日信度較差。結論：雙數位式傾斜儀於測量健康年輕人之胸椎後凸角度和活動度上，具有良好信度，可提供研究與臨床使用之量化工具的選擇。

great value for evaluating patients’ thoracic spine posture and movement. Dual Digital Inclinometer (DDI) is a noninvasive device that is able to measure the kyphosis angle and spine mobility. The purpose of this study was to determine the intra-tester reliability of a DDI in measuring the TKA and the mobility of thoracic °exion, extension, side °exion and rotation in healthy adults. Methods: In this study, the TKA and each direction of the thoracic mobility was measured by the DDI in 5 men and 5 women with an average age of 23.4 years old. The ÿrst two measurement sessions were arranged with 30 minutes apart on the same day to assess the within-day reliability for each measurement. The third measurement was taken on the next day to assess the between-day reliability for each measurement. Each measurement was taken three times for calculating its average. The intraclass correlation coe˝cients (ICC), the standard error of measurement (SEM), and the minimal detectable change with 95% conÿdence (MDC95) were used to determine the strength of the reliability. Results: The reliabilities of the TKA and the thoracic mobility of °exion, extension, side °exion, and rotation measured by the DDI were shown to be good with high ICC values, ranging from 0.87 to 0.99 for the within-day data. The range of the SEM was from 0.7 to 2.9° (MDC95 = 1.91 to 8.32°). The between-day reliability of the TKA and the thoracic mobility of °exion, extension, and rotation were moderate with the ICC values ranging from 0.77 to 0.93. The range of the SEM was 1.5 to 3° (MDC95 = 4.13 to 8.32°) for the between-day data. However, the between-day reliability of the thoracic side °exion was poor (ICCs = 0.25 to 0.57, and the SEMs = 3.3 to 5.1°). Conclusions: The DDI is a reliable device for the measurement of TKA and the thoracic mobility of °exion, extension, and rotation in healthy adults. The reliability of DDI in measuring thoracic side °exion was poor.