本研究目的在比較傳統以最大努力跑步至衰竭時間所推算的臨界速度(critical velocity;CV),與非最大運動攝氧量與心跳率所推算的CV是否有差異存在。同時針對不同強度非最大運動時間所推算之CV強度,進行氧攝取量、心跳率與肌電圖(EMG)等人體生理反應的變化分析,以便確認非最大運動時間推算CV方法之有效性。 本研究以20名經常參與運動的男大學生(20.45±0.83歲、177.30±6.21公分、71.62±6.45公斤)為受試對象,受試者除了先接受一次最大攝氧量及最大心跳率測驗外,所有受試者需接受四個不同強度跑步的CV測量。進行CV測量時,同時蒐集受試者之攝氧量與心跳率,以利從各強度跑步至90%、80%和70%目標攝氧量與心跳率之時間推算非最大運動攝氧量與心跳率CV。最後,以CV強度進行最長時間30分鐘固定強度的運動測驗,運動測驗過程中的第5、10、15、20、25與30分鐘,記錄每位受試者的攝氧量、心跳率與肌電圖變化。結果發現以傳統最大努力跑步至衰竭時間所推算的CV(3.54±0.318m/s)與CV90%VO2max、CV80%VO2max與CV90% HRmax (3.64±0.387、3.56±0.410和3.60±0.354m/s)無顯著差異,同時,與無氧閾值、最大攝氧量和無氧閾值速度的相關皆達顯著水準(0.63~0.73),顯示非最大運動攝氧量和心跳率所推算的CV與傳統運動至衰竭時間皆可有效推算CV。另外,本研究以實用性較高與SEE最低之CV90% HRmax持續30分鐘運動時,肌電圖與攝氧量無顯著變化,顯示以此強度運動30分鐘,攝氧量呈現穩定狀態,股外側肌無疲勞現象發生。
The purposes of this study were 1) to examine the difference between critical velocity (CV) derived from submaximal exercise time and maximal exercise time, and 2) to examine the validity of CV derived from submaximal exercise time. Subjects were 20 college students(20.45±0.83yrs, 177.30±6.21cm, 71.62±6.45kg). Participants performed five exhaustive treadmill tests and a 30-min continuous treadmill tests at CV. The purpose of the first test session was to determine VO2max, HRmax and ventilatory threshold. At the next four sessions, each subject performed four exhaustive constant velocity tests (3.5m/sec~6m/sec). During each test, expired gases and HR were analyzed. CV was derived from submaximal exercise VO2 and HR at each velocity. Secondly, participants performed a 30-min continuous treadmill tests at their CV. During the test, the VO2, HR and electromyography (EMG; RMS & MPF) responses from treadmill and examined the validity of CV derived from submaximal exercise time were determined. The results were: 1) CV derived from submaximal exercise time (CV90%VO2max, 3.64±0.387; CV80%VO2max, 3.56±0.410; CV90%HRmax, 3.60±0.354m/s) and maximal exercise time were (3.54±0.318m/s) not significantly different, but were significantly correlated (0.63~0.73). 2) When running a 30-min continuous treadmill tests at their CV, HR increased with time, but RMS, MPF and VO2 remain unchanged.