目的：經由退化性膝關節炎 (knee osteoarthritis, KOA) 風險角度檢測，探討規律參與運動的中年人與中老年人是否有較高的 KOA 罹患風險。方法：招募規律運動習慣的實驗參與者共 14 位，分為中年組 7 位 (年齡為44.1 ± 4.7歲)，以及中老年組 7 位 (年齡為59.0 ± 8.8歲)。使用 2 台高速攝影機拍攝膝關節內外翻角度，以及Noraxon無線肌電感測系統分析股內側肌與股外側肌之肌肉活化特徵，使用描述性統計分析兩組實驗參與者是否有 KOA 風險的角度特徵，以及經由獨立樣本 t-test 比較中年組與中老年組在膝關節內外翻角度與肌肉活化特徵之差異，顯著水準設 α = .05。結果：中年組膝內翻角度為 0.71 ± 2.9˚，中老年組為 2.14 ± 4.4˚，以上皆小於罹患 KOA 之風險角度 (內翻 3˚)，兩組間無顯著差異。兩組實驗參與者在步行時，股內側肌與股外側肌的活化程度相似，無顯著差異。股內側肌與股外側肌之活化比例與活化時間差值，在兩組之間皆未達顯著差異。結論：在本研究中未發現長期規律運動的中年人與中老年人有較高的退化性膝關節炎罹患風險，膝內翻角度皆未超過罹患 KOA 的風險角度值，平均年齡接近 60 歲的中老年組，KOA 風險角度的平均值仍低於 3°，因此適度的運動對膝關節健康應有正面的效益。

Purpose: Through detecting Knee Osteoarthritis (KOA) risk perspective, to explore whether middle-aged and middle-aged people who regularly participate in sports have a higher risk of KOA. Methods: Fourteen participants with regular exercise habits were recruited and divided into the middle-aged group (seven participants aged 44.1 ± 4.7 years old) and the pre-elderly group (59.0 ± 8.8 years old). Two high-speed cameras were used to capture the varus and valgus angles of the knee joint, and the Noraxon wireless electromyography system was used to analyze the muscle activation characteristics of the vastus medialis and vastus lateralis muscles. Descriptive statistics were used to analyze the angle characteristics of whether the two groups of experiment participants were at risk of KOA. And through the independent sample t-test to compare the differences between the middle-aged group and the pre-elderly group in the varus angle and muscle activation characteristics of the middle-aged group, the significance level was set at α = .05. Results: The knee varus angle was 0.71 ± 2.9° in the middle-aged group, and 2.14 ± 4.4° in the middle-aged and elderly group, all of which were smaller than the risk angle of KOA (varus 3°) and there was no significant difference between the two groups. The activation of the vastus medialis and vastus lateralis was similar between the two groups of participants during walking, with no significant difference. There was no significant difference between the two groups in the activation ratio and activation time difference of vastus medialis and vastus lateralis. Conclusion: In this study, it was not found that middle-aged people and pre-elderly people who exercise regularly for a long time have a higher risk of degenerative knee arthritis, and the angle of knee varus does not exceed the risk angle value of KOA, and the average age is close to 60 years old in the pre-elderly group, the average KOA risk angle was still lower than 3°; therefore moderate exercise should have a positive effect on knee joint health.