橢圓機坡度改變對下肢肌群肌電訊號與生理反應之影響

Lower extremity muscle activation and physiological response to different inclines of exercise on elliptical trainer

Agile Trainer型橢圓機為透過連桿角度的改變，達到改變橢圓機的踩踏軌跡與坡度改變的效果。目的：探討不同橢圓機坡度運動下肢肌群（脛前肌、腓腸肌、股直肌、股二頭肌、臀大肌）肌電訊號與生理反應之差異。方法：8名受試者（年齡：25.6±4.7歲；身高：178.13±5.3公分；體重：79.0±16.4公斤）依據平衡次序，從事不同橢圓機坡度（0％，9.3％與18.6％）0負荷，每次踩踏進行3分鐘，踩踏頻率分別設定30rpm與60rpm，兩組踩踏頻率實驗間休息24小時以上，每次測驗在橢圓機坡度變化間，皆以坐姿休息5分鐘，資料擷取受試者踩踏穩定的120秒（運動後第2分鐘開始）。由Acq Knowledge3.8.2生物訊號分析軟體計算每個週期平均的均方根振幅（root mean square，RMS），再將每個坡度RMS除以最大值，以百分比相對強度（％RMSmax）呈現，探討不同坡度的變化情形。同時，在運動過程中，蒐集攝氧量與心跳率資料。結果：除了脛前肌會隨著橢圓機坡度的增加，％RMSmax值呈現顯著下降的趨勢；其他的肌群（腓腸肌、股直肌、股二頭肌、臀大肌）隨著橢圓機坡度增加，％RMSmax值顯著增加（p＜.05）。生理反應方面在60rpm的橢圓機運動攝氧量與心跳率顯著大於30rpm的橢圓機運動，攝氧量隨著橢圓機坡度的增大而顯著提昇。結論：可變橢圓機坡度橢圓機（Agile Trainer型），具備隨著橢圓機坡度增加，改變下肢肌群參與情形，以及逐漸增加生理負荷的趨勢。Purposes: To investigate how muscles of lower extremity response to different training inclines on elliptical trainer via measuring EMG and several physiological parameters. Methods: Eight volunteer subjects (age: 25.6 ± 4.7 yrs, height: 178.1 ± 5.3 cm, weight: 79.0 ± 16.4 kg) performed six trials, which were composed of three different incline elliptical trainer exercises (0%, 9.3% and 18.6%) and two different cycling frequencies (30 and 60 rpm). Each exercise trial took 3 minutes and data acquisition was started at the 2nd minute to the end of each trial. A five-minute sedentary rest was set between each exercise trail. Average of root mean square (RMS) for every cycle was calculated by a software AcqKnowledge 3.8.2. Then, RMS from every incline was divided by the maximal value of acquired data and presented as percent RMS maximal (%RMSmax). In addition, oxygen intake (V.O2) and heart rate (HR) were measured during all exercise trials. Results: With increased training incline, most muscles showed increased trend in %RMSmax except for a decreased trend revealed in %RMSmax of tibialis anterior (TA). Moreover, values of %RMSmax showed significant difference among different training incline. Regarding physiological parameters, V.O2 and HR responses were greater under 60 rpm of elliptical exercise than those under 30 rpm. Conclusion: The elliptical trainer (Model: Agile Trainer) could vary muscle recruitment pattern of lower limbs through incline adjustment.