目的：探討4週高強度循環訓練 (high-intensity circuit training, HICT) 與耐力訓練 (endurance training, ET) 對心肺適能、心率變異性 (heart rate variability, HRV)、身體組成與運動中的脂質代謝之影響。方法：招募36名健康男性，依前測之最大攝氧量 (maximal oxygen uptake, VO2max) 分派至HICT (每組12個動作執行30秒，動作間休息10秒) 、ET [以第一換氣閾值 (first ventilatory threshold, VT1) 所對應之強度，於跑步機上進行運動30－45分鐘] 與CON (不訓練)。所有受試者於4週前、後分別進行遞增負荷運動測驗 (graded exercise test, GXT)、安靜狀態下HRV指標 (時域與頻域分析) 評估與皮脂厚測量 (胸部、下腹部與股四頭肌)。脂質代謝會使用GXT前數個階段，呼吸交換率 (respiratory exchange ratio, RER) 低於或等於1.0時的資料進行分析。結果：VO2max、安靜狀態下HRV指標與運動中的脂質代謝在組別因子與時間因子之交互作用皆未達顯著差異 (p > . 05)。VO2max所對應的跑步速度 (vVO2max) 在HICT與ET訓練後有顯著進步 (前測vs.後測：HICT，15.3 ± 1.1 vs. 15.8 ± 1.2 km/hr；ET，14.9 ± 1.4 vs. 15.7 ± 1.1 km/hr，p < .05)，而HICT與ET之間未達顯著差異 (p > . 05)；遞增負荷運動至衰竭的時間在HICT訓練後有顯著提升 (前測vs.後測：2160.0 ± 267.5 vs. 2209.7 ± 265.3秒，p < .05)；VT1所對應的VO2max百分比 (%VO2max at VT1)，HICT與ET (前測vs.後測：HICT，50.9 ± 7.7% vs. 57.1 ± 9.9%；ET，50.9 ± 8.4% vs. 58 ± 6.2%，p < .05) 訓練後均顯著提升，而ET後測顯著高於CON後測 (48.9 ± 11 %, p < .05)；HICT與ET的皮脂厚總和 (前測vs.後測：HICT，47.8 ± 11.8 vs. 44.1± 10.8 mm；ET，51.7 ± 13 vs. 46.8 ± 13.1 mm) 與體脂肪百分比 (前測vs.後測：HICT，13.7 ± 3.4 vs. 12.7 ± 3.1%；ET，14.8 ± 3.9 vs. 13.4 ± 4%) 在訓練後均顯著下降。然而，GXT前期的脂質代謝在組別因子與時間因子之交互作用未達顯著差異。結論：4週的HICT與ET可以提升規律運動者心肺適能並改善體脂肪百分比，但無法改善安靜狀態下自律神經系統的調控與運動中的脂質代謝。

關鍵詞：脂質代謝、體重訓練、有氧適能、身體組成、高強度間歇訓練

Purpose: The purpose of the study was to investigate the effects of 4 weeks of high intensity circuit training (HICT) and endurance training (ET) on cardiopulmonary fitness, heart rate variability (HRV), body composition, and fat oxidation rate during exercise. Methods: 36 active male adults were recruited and assigned to HICT (12 callisthenic exercises were performed for 30-s with 10-s rest interval), ET [ran at first ventilatory threshold (VT1) for 30–45 minutes on a treadmill] and control (CON, no training) groups according to the initial maximal oxygen uptake (VO2max). Before and after 4-week training, all participants were asked to perform the graded exercise test (GXT), resting HRV indices (time and frequency domain), and skinfold thickness (chest, abdominal, thigh). During GXT, the fat oxidation rates were further analyzed at first few stages which respiratory exchange ratio was less than or equal to 1.0. Results: No significant interaction effects were observed in VO2max, HRV indices at rest, and fat oxidation during exercise (p > .05). The velocity at VO2max (vVO2max) was significantly improved after HICT and ET (HICT, from 15.3 ± 1.1 to 15.8 ± 1.2 km/hr; ET, from 14.9 ± 1.4 to 15.7 ± 1.1 km/hr, p < .05); however, there were no significant differences between HICT and ET (p > .05). Time to exhaustion during GXT was significantly extended after HICT (from 2160.0 ± 267.5 to 2209.7 ± 265.3 s, p < .05). The percentage of VO2max at VT1 (%VO2max at VT1) were significantly increased after HICT and ET (HICT, from 50.9 ± 7.7% to 57.1 ± 9.9%; ET, from 50.9 ± 8.4% to 58 ± 6.2%, p < .05). The %VO2max at VT1 after ET was significantly higher than that in CON (48.9 ± 11 %, p < .05). The sum of skinfold thickness at 3 sites (HICT, from 47.8 ± 11.8 to 44.1± 10.8 mm; ET, from 51.7 ± 13 to 46.8 ± 13.1 mm) and body fat percentages (HICT, from 13.7 ± 3.4 to 12.7 ± 3.1%; ET, from 14.8 ± 3.9 to 13.4 ± 4%) were significantly decreased after HICT and ET. However, no significant interaction effects were found in fat oxidation rates at early period of GXT. Conclusion: 4 weeks of HICT and ET might improve cardiopulmonary fitness and percent body fat, but not for the modulation of autonomic nervous system at rest and fat oxidation during exercise in active individuals.

Keywords: fat oxidation, body weight exercise, aerobic fitness, body composition, high-intensity interval training

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