30分鐘臨界速度跑步的脂肪代謝變化研究

Fat oxidation of 30 minutes running on critical velocity

臨界速度（critical velocity,CV）代表人體可以持續運動極長時間的最大運動強度。瞭解CV跑步過程的脂肪代謝變化，可以作為設定運動強度的依據，以便提高運動參與的效益。目的：本研究目的在瞭解30分鐘的CV跑步過程中，以間接測量的方式探討脂肪代謝的變化情形，並且進一步探討脂肪代謝的變化是否會因為運動時間的增加而改變。方法：以年齡20.35±0.78歲、身高177.41±6.11公分、體重71.55±6.76公斤、最大攝氧量53.67±3.66ml/kg/min經常運動的大學體育系男生17人為受試對象，每位受試者依平衡次序的方式，進行四次不同強度的最大持續跑步時間測驗，並且計算出受試者的CV；最後受試者以CV的強度進行30分鐘的跑步，同時利用Vmax29能量代謝系統，紀錄受試者在跑步過程的攝氧量（oxygen intake,V.O2）、呼吸交換率（respiratory exchange ratio,RER），並且透過V.O2與RER間接測量跑步過程中的脂肪代謝變化。結果：在30分鐘的臨界速度（4.58±0.25m/s）跑步過程中，第10、20、30分鐘時的V.O2分別為41.31±4.10ml/kg/min、42.14±3.65ml/kg/min、42.65±4.16ml/kg/min，RER分別為0.97±0.02、0.98±0.01、0.97±0.02，脂肪代謝率分別為0.15±0.10g/min、0.12±0.08g/min、0.15±0.09g/min。結論：經常運動者以CV強度進行30分鐘的跑步運動時，不僅不會增加運動時的V.O2，也不會改變脂肪代謝的比例。

Critical velocity (CV) is the maximal intensity that people can exercise continually for long time. We can elevate the benefit of exercise if the changes of fat oxidation running on CV were understood. Purpose: The purpose of this study was to investigate the changes of fat oxidation during running on CV for 30 minutes. Methods: 17 activity male university students (age 20.35 ± 0.78 yr, height 177.41 ± 6.11 cm, weight 71.55 ± 6.76 kg, V.O2max 53.67 ± 3.66 ml/kg/min) participated in this study. Each subject followed counterbalance order to perform four running tests of different intensities on treadmill. The maximal exercise time were recorded during four running tests. CV was calculated according to the measurement data of four running tests. Then each subject ran 30 minutes continually on CV , and oxygen intake (V.O2) and respiratory exchange ratio (RER) were recorded during CV running. The changes of fat oxidation were indirectly calculated according to V.O2 and RER. Results: During 30min running on CV, V.O2, RER and fat oxidation rate of 10th, 20th, and 30th minute were 41.31 ± 4.10 ml/kg/min, 42.14 ± 3.65 ml/kg/min, 42.65 ± 4.16 ml/kg/min; 0.97 ± 0.02、0.98 ± 0.01、0.97 ± 0.02 ; 0.15 ± 0.10 g/min, 0.12 ± 0.08 g/min, 0.15 ± 0.09 g/min respectively. There were no any significantly differences. Conclusion: When running on CV for 30 min, neither did V.O2 increase nor did fat oxidation rate change.