本研究的目的在探討4週高強度循環訓練（high-intensity circuit training, HICT）與耐力訓練（endurance training, ET），對有氧適能（包括最大攝氧量[maximal oxygen uptake, VO_(2max)]和最大速度[running velocity at VO_(2max), vVO_(2max)]）及肌肉表現（包含最大等長肌力和發力率[rate of force development, RFD]）的影響。本研究招募36位健康男性，以前測的VO_(2max)為分組指標，將受試者平均分派至HICT組、ET組和控制組（control, CON），分別進行4週訓練，CON則不進行額外訓練。在HICT組，每週須進行3次1～3組，每組6分鐘的HICT，組間休息5分鐘。ET組則在跑步機上進行每週3次，持續30～45分鐘的跑步運動。每位受試者在4週訓練的前、後，須進行遞增負荷運動測驗，以評估VO_(2max)和vVO_(2max)，以及在測力板上，進行最大等長肌力測驗，檢測力量峰值、力量平均值、最大發力率（RFD_(max)）及分段RFD在0～30、0～90、0～150、0～200、0～250毫秒等指標。本研究結果發現HICT組在訓練後RFD_(max)顯著高於前測，並且訓練後RFD_(max)、RFD_(0～30)和RFD_(0～90)皆顯著高於CON和ET組（僅RFD_(0～90)）。而VO_(2max)、力量峰值和平均值，訓練前、後及3組間無明顯差異，但VO_(2max)在HICT和ET皆明顯提升。本研究的結論為4週HICT和ET可提升規律運動者的心肺耐力表現，但無法改善下肢等長肌力。

The purpose of this study was to investigate the effect of 4-week high-intensity circuit training (HICT) and endurance training (ET) on aerobic fitness (maximal oxygen uptake [VO_(2max)] and maximal velocity [vVO_(2max)]) and muscular performance (maximum isometric strength and rate of force development [RFD]) in physically active adults. Thirty-six healthy males were recruited for this study, and equally assigned into HICT, ET, or control (CON) groups based on their VO_(2max) at pre-training. Four weeks training was conducted for participants in both HICT and ET groups, whereas those in CON group did not receive any structured training. Participants in HICT group performed 1-3 sets of exercises, 3 times a week, and each set containing 6 min HICT with 5 min rest between the sets. Participants in ET group ran on a treadmill for 30-45 min thrice a week. All participants performed graded exercise tests before and after 4-week training. The VO_(2max) and vVO_(2max) of participants were evaluated. The peak force, average force, maximum RFD (RFD_(max)) and RFD in periods of 0-30, 0-90, 0-150, 0-200, and 0-250 ms were monitored with maximum isometric strength test on the force platform. The results showed that RFD_(max) in HICT group was significantly higher after 4 weeks than the value at pre-training. Moreover, the RFD_(max), RFD_(0-30) and RFD_(0-90) in HICT group after training were significantly higher than those of CON and ET groups (only RFD_(0-90)). There were no significant changes in VO_(2max), peak and average isometric force before and after training in all groups. However, vVO_(2max) was significantly increased in the HICT and ET groups. In conclusion, 4 weeks HICT and ET might be effective in improving the cardiopulmonary endurance performance in active individuals, but unable to improve the lower limbs isometric strength.