緒論：本研究探討不同自行車之市售輪組及戶外騎乘不同地形對下肢肌肉活化之影響。方法：本研究對象為12名有運動習慣之大專男生(平均年齡19.5 ± 1.7歲；平均身高174.7 ± 4.7公分；平均體重69.7 ± 7.14公斤)利用肌電感測儀觀察兩款不同市售輪組在不同地形騎乘的下肢肌肉活性之影響，將肌電感測儀分別黏貼於股內側肌、股外側肌、股直肌、股二頭肌、脛前肌及腓腸肌6個肌群，取樣頻率為1000 Hz。使用二因子重複量數變異數分析分析兩款不同市售輪組對於下肢肌肉活化程度，顯著水準訂為α = .05。結果：本研究結果得知，G牌比P牌的下肢肌群活化程度沒有顯著差異；但是在不同地形騎乘時的肌肉活性有顯著差異，股外側肌、股二頭肌及脛前肌肌肉活化在下坡小於上坡、腓腸肌肌肉活化在下坡小於平路，平路小於上坡。結論：一般自行車愛好者在挑選輪組時，重量不是挑選輪組的唯一考量，可以隨自己喜好參考它們的性能及價格進行挑選，再者，因應不同地形的變化，腓腸肌在騎乘過程中扮演著重要的角色。

Purpose: The aim of this study was to investigate lower limb muscle activation differences by riding different commercially available bike wheels on three terrains (ascent, descent, and flat). Methods: This study recruited 12 male college students (mean age: 19.5±1.7 years old, mean height: 174.7±4.7 cm, mean body mass: 69.7±7.14 kg). All of the participants performed regular weekly exercise routines. To obtain access to the lower limb muscle activation data, six electromyography sensors were positioned on the vastus medialis, vastus lateralis, rectus femoris, biceps femoris, tibialis anterior and gastrocnemius. The sampling rate was set as 1000 Hz, and two-way repeated measures ANOVA was applied to analyze the relationship between different bike wheels and lower limb muscle activation. All statistical measurements were performed using SPSS 22.0, and a significance level of α = .05 was adopted. Results: Referring to the test results, lower limb muscle activation showed no significant difference between the G wheel and the P wheel. However, when riding on different terrains, the vastus lateralis, biceps femoris and tibialis anterior muscle activation rates were found to be significantly lower during descents than during ascents. In terms of the gastrocnemius, the muscle activation rate was lower during descents than on horizontal terrain. Comparing ascents to horizontal terrain, the former induced higher muscle activation in the gastrocnemius during the trial. Conclusion: In summary, it is recommended that cyclists choose bike wheels that are able to meet their personal needs, such as functional demands, price, weight, and rim height. Weight itself is not the only consideration for selecting bike wheels, etc. Furthermore, in regard to cycling on different kinds of terrains, it was indicated that the gastrocnemius plays an important role during rides. If the rider can increase the muscle activation rate in the gastrocnemius, it is possible that performance can be enhanced.