實驗設計：探究性研究。目的：本實驗欲探究超音波影像測量參數與性別、年齡、身體質量指數(BMI)以及體重等因子之關係。背景：本實驗利用影像超音波量測腹橫肌(Transversus abdominis TrA)之肌肉厚度變化及肌肉－筋膜連結之滑動量變化(lateral sliding of muscle-fascia junction)。方法：本實驗徵召37位20至35歲沒有復發性下背痛之受測者。使用超音波影像(HDI 5000 Philips/ATL, Bothell, WA, USA)紀錄肌肉－筋膜連結之滑動變化(△x)、休息時肌肉厚度(Thr)、最大收縮厚度(Thm)以及厚度變化比(Thm-Thr/Thr)。以配對t核定(paired t-test)來檢驗超音波測量參數之左右一致性、以Pearson product-moment correlation coefficient檢驗超音波測量參數與性別、年齡及其他人體測量參數如體重及BMI之相關性。Partial correlation用來檢測控制體重因素下，性別與超音波參數的相關性。結果：兩側的超音波測量參數皆無顯著差異，顯示彼此具有左右一致性。性別與TrA之△x(r=0.34)、Thr(r=0.57)、Thm(r=0.43)；腹內斜肌(Obliquus Internus, OI)之Thr(r=0.69)及Thm(r=0.60)之間則有顯著相關。在控制體重因素後，則TrA之△x與Thr；TrA之Thm與性別則無顯著差異。年齡與超音波測量參數之間無顯著相關。體重與△X(r=0.37)、TrA之Thr(r=0.62)及Thm(r=0.51)、OI之Thr(r=0.54)及Thm(r=0.54)之間有正相關。BMI與TrA之Thr或Thm有正相關(r=0.45 or 0.44)。結論：兩側之超音波測量參數具有致性。未來進行超音波測量參數評估時，需考慮的影響因子如體重及其對性別及年齡之影響。

Study Design: Cross-sectional. Objective: The purpose of this study was (1) to investigate whether the measurement of thickness and lateral sliding of the muscle-fascia junction of trans-versus abdominis (TrA) by ultrasound imaging was symmetrical: (2) to explore the relationship between these parameters and gender, age, BMI and weight: (3) to examine the influence of weight on the observed relationship between gender and ultrasound measurements. Summary of Background: Ultrasound imaging was employed to provide information about the shape. performance of contraction, change of muscle thickness between resting and contraction, and lateral sliding of muscle-fascia junction of TrA. However, few studies investigated the factors influencing the measurements of changes in thickness and sliding during contraction. Methods: Thirty-seven subjects (20-35 years old) without LBP were recruited. The ultrasound imaging equipment used in this study was HDI 5000 (Philips/ATL. Bothell, WA, USA). The outcome measures included the lateral sliding of the muscle-fascia junction (△x), resting thickness (Thr) maximal contracting thickness (Thm), and contraction ratio (Thm/Thr). The participants performed abdominal draw-in maneuver in hook-lying position. Real-time ultrasonographic image was taken for off-line measurement. The paired t-test was employed to examine the symmetry of muscle thickness and lateral sliding of the muscle-fascia junction of TrA measured by ultrasonography. Pearson product-moment correlation coefficient was utilized to measure the correlation between ultrasound measurements of abdominal muscle, and gender, age, weight and BMI Partial correlation vas employed to assess the relationship between gender, and muscle thickness and lateral sliding of muscle-fascia junction of TrA with the effect of weight eliminated. Results: There was no significant difference in measurement of thickness and lateral sliding of muscle-fascia junction of TrA on both sides. There was significant positive correlation between gender and △x (r=0.34 ), Thr of TrA (r=0.57). Thm of TrA (r=0.43), Thr of obliquus internus (OI) (r=0.69), and Thm of OI (r=0.60). However, there was no significant relationship between gender and △x and Thr, Thm of TrA when partial correlation coefficients were calculated between gender, and thickness and lateral sliding of muscle-fascia junction of TrA controlling for weight. There was no significant correlation between age, and thickness and lateral sliding of muscle-fascia junction of TrA. There was significant positive correlation between weight, and △x (r=0.37), Thr of TrA (r=0.62), Thm of TrA (r=0.51), Thr of OI (r=0.54), and Thm of OI (r=0.54) Conclusions: Ultrasonic measurement of thickness and lateral sliding of the muscle-fascia junction of TrA were symmetrical on both side. The weight and gender should be controlled when comparing the measurement of abdominal muscles between groups by ultrasound imaging in future study.