目的：本研究目的為(一)探討正常兒童與腦性麻痺兒童的下肢肌肉骨骼系統評估之不同測試者問及測試者內信度，(二)探討正常兒童與腦性麻痺兒童的下肢肌力及關節活動度與平衡活動功能的相關性。方法：痙孿型腦性麻痺兒童及正常兒童各12名分別接受兩名物理治療師測試兩次，以手握測力器測4組量化下肢肌力及以量角尺量下肢5組關節角度，並以功能性伸取測試及計時起身行走測試做為平衡檢查。以內在等級相關係數（Intraclass Correlation Coefficient，簡稱ICC）做為不同測試者問和測試者內信度，再以皮爾森積差相關係數分析(r)做為相關性統計分析。結果：肌力及被動關節角度不同日同一施測者測量信度為中到好信度(ICC=0.56~0.97)，第一天同日不同施測者測量信度也是中度到好信度(ICC=0.41~0.88)。功能性伸取測試與膝膕角呈現顯著中低度到中度正相關性(r=0.37~0.56, P<0.05)，計時起身行走測試與膝膕角呈現顯著中低度負相關性(r=-0.48~-0.49, P<0.05)。結論：研究結果顯示肌力及關節角度測試可做為未來研究正常兒童與腦性麻痺兒童的工具。此外，膝膕角與平衡有相關性，未來值得進一步探討膝膕角對於兒童平衡的影響。

Background and Purpose: The purpose of this study was to determine the reliabilities of clinical measurement in lower extremities, including muscle strength and passive range of movement (PROM), for children with typical development (TD) and children with cerebral palsy (CP). Methods: Two physical therapists worked in pairs and measured 12 children with TD and 12 children with CP on two occasions using a repeated measures design. The PROM was measured by goniometer and standardized mean strength was assessed using a hand-held dynamometer. Functional reach test (FRT) and time up and go test (TUG) were measured as balance function. Interrater and intrarater reliability were examined by Intraclass Correlation Coefficient (ICC). Pearson correltion coefficient was used to determine the relationships among PROM, muscle strengths, and balance tests. Results: Moderate to good intrarater reliability (ICC=0.56~0.97) and interrater reliability (ICC=0.41~0.88) were noted for muscle strength and PROM. The relationships between FRT and popliteal angle were fair to moderate positive correlation (r=0.37~0.56, p<0.05), and fair to moderate negative correlations (r=-0.48~-0.49, p<0.05) between TUG and popliteal angle were noted. Conclusions: The findings support that the clinical usage of muscle strength and PROM measurements for children with TD and children with CP can be reliable. In addition, the influence of popliteal angle to the balance control of children with CP is worth to examine in future because the fair to moderate relationships between popliteal angle and functional balance tests was noted.