背景與目的：腹部肌群有一重要功能是幫助穩定骨盆與腰椎，使人體在從事運動或日常生活活動 中能隨時保護脊椎以避免腰椎受傷。下肢負重測試常被用來測量腹部肌群穩定腰椎與骨盆的能力。 因此，本研究的主要目的在於以腹肌測試（abdominal muscle test, AMT)與雙腳下降測試（double-leg-lowering test, DLLT)來瞭解健康受試者腹部肌群穩定腰椎的能力，以及這兩個下肢負重測試結 果之相關性，並一併驗證兩測試的信度。方法:研究中共徵求35位健康女性受試者，平均年齡為 22.6歲（範圍18-34歲)。由兩位物理治療系學生與兩位治療師；fc責執行AMT與DLLT。在執fl兩個 下肢負重測試時，會在受試者下背部放置壓力生物回饋儀以監測骨盆g否發生前傾。受試者需先 練習並學會使用腹肌收縮以使在執行下肢動作時骨盆可保持在後傾的置。AMT之評分等級為1 至4分；DLLT之評分等級為5至10分。統計方式以Spearman等級相關係數（rs)來檢驗兩測試之間 的相關性•》'因皆屬序位變項’因此採用Spearman等級相關係數來進行兩次測量間相關性的分析， 並以加權卡帕（weighted kappa, kw)係數來表不兩次測量致性的程度結果：受試者在AMT測 試的表現，中位數與平均數分別是3分（範圍2-4分）與3.1_:0.5分，其中有28人（80%)為3分。 而在DLLT的表現，中位數與平均數分別是8分（範圍5-10分）與7.5±1.5分•在6個等級分數的受 試者人數（百分比）則較分散，範圍從2人（5.7% )至11人（31.4% )。AMT與DLLT的表現達顯著 相關（rs=0.72，p<0.001).°_AMT的施測者內或施測者間信度分析結果’ rs的值分別為0.93與0.87 ’ 表示具高度相關（rs&0.7)；而匕的值分別為0.92與0.84，顯示具有優良（kw 3 0.81)的一致性 DLLT的分析結果也顯示具有良好的施測者內或施測者間信度，rs的值分別為0.98與0.83，而kj勺 值分別為0.95與0.80。結論與臨床意義：雖然兩測試皆具有良好的測試者間與施測者內信度，但 因為AMT較無法區辨健康女性腹部肌群的穩定能力，所以並不利於健康年輕女性之應用。因此’ 本研究建議可使用DLLT此下肢負重測試來測量健康女性其腹部肌群穩定腰椎與骨盆的能力。本研 究健康女性在AMT與DLLT的腹肌穩定能力表現與施測方式與步驟，可作為物理治療師在臨床使 用時之參考。（物理治療2012;37(4):297-308 )

Background and Purpose: One of the major functions of the abdominal muscles is to stabilize the spine, which prevents lumbar injuries and allows coordinated limb movements in sports and activities of daily living. Leg loading tests are frequently used to assess this stabilizing ability of the abdominal muscles. The purpose of this study was to describe the pelvic tilt motor control required to maintain lumbar stability as measured by two leg loading tests, abdominal muscle test (AMT) and double-leg-lowering test (DLLT), in healthy women. In addition, the intra-rater and inter-rater reliability were also determined. Methods: Thirty-five healthy women with mean age 22.6 years (between 18 and 34 years old) volunteered to participate in the study. A repeated measures reliability study was conducted by two teams of two examiners, two students and two physical therapists. All DLLT and AMT measurements were tested using a pressure bio-feed-back unit placed beneath the low back to detect pelvic motion. The subjects were instructed and practiced to contract the abdominal muscles to maintain the pelvis in a posterior tilted position while performing the leg lowering in the two leg loading tests. The AMT is an ordinal scale with 4 levels, and the DLLT is also an ordinal scale with 6 scores. The correlation between AMT and DLLT performance were obtained using Spearman’s rank correlation coefficient (rs). Spearman’s correlation coefficient (rs) and weighted kappa (kw) were used to examine the level of agreement between two measurements for the two ordinal measures. Results: The median and mean values for AMT were 3 (2-4) and 3.1 ±0.5. Of the 35 healthy young female, most of them (28，80%) were grade 3. The median and mean values for DLLT were 8 (5-10) and 7.5±1.5. The number of subjects was distributed over the 6 grades of DLLT, ranged from 2 (5.7 %) to 11 (31.4%).
There was a high correlation between AMT and DLLT performance (rs=0.72, p<0.001). Intrarater and inter-rater agreements were high for the AMT, with Spearman r (rs) values of 0.93 and 0.87; and with weighted kappa (kw) values of 0.92 and 0.84, indicating very good agreement. Intra-rater and inter-rater agreements were also high for the DLLT, with Spearman r (rs) values of 0.98 and 0.83; and with weighted kappa (kw) values of 0.95 and 0.80, indicating very good agreement. Conclusion: Although the AMT and DLLT were shown to high levels of intra-rater and inter-rater reliability in healthy women, we recommended the DLLT may be a useful tool to assess pelvic tilt control for spine stability in the healthy young women. The results of the lumbar stability measures, by using AMT and DLLT, in the healthy female provide reference data to enable comparison with clinical group. (FJPT 2012;37(4):297-308)