全身振動訓練協同輕阻蹲跳訓練對小腿後肌神經適應性之影響

Abstract

背景與目的：肌力、爆發力和跳躍能力能決定運動表現的好壞，傳統上常使用高強度阻力訓練、爆發力訓練或增強式訓練來提昇運動表現。近年來，全身振動訓練（whole body vibration training）受到運動界和醫學界的重視，其特色是，振動平台能提供較大的重力加速度，並同時刺激本體感覺神經，在訓練時誘發肌肉作更強收縮，學者認為此訓練方法可以強化肌力和爆發力，但神經肌肉系統經過此訓練所獲得的效益及改變機轉尚未被完整之實驗設計所驗證，而且全身振動訓練搭配其它訓練方式，與傳統式全身振動訓練機轉之間的差異也未被進一步研究。方法：本研究共徵召24位健康的大專院校運動員，並把他們分配成三組，分別是全身振動協同輕阻蹲跳訓練組、全身振動訓練組或輕阻蹲跳訓練組。全身振動協同輕阻蹲跳訓練組在振動平台上進行8週輕量荷重的跳躍訓練，全身振動訓練組需要在振動平台上維持半蹲的姿勢，輕阻蹲跳訓練組則是在平地上進行輕量荷重跳躍訓練，訓練頻率為每週3次。所有受試者將接受兩次測試：前測、和後測（訓練8週），測試項目包括：脊髓及脊髓上運動神經元總和興奮性（spinal and supraspinal motor-neuron excitability）、神經活化程度（neural activation level）和運動能力之表現。將使用SPSS套裝軟體分析資料，使用重覆量數變異數分析（two-way repeated-measures ANOVA）或Kruskal-Wallis測試，檢定全身振動協同輕阻蹲跳訓練、全身振動訓練和輕阻蹲跳訓練在各依變項變數造成之改變，並使用Pearson相關性檢定方法，檢定各參數之間的相關性，統計之顯著水平訂定為p<0.05。結果：本研究的結果顯示，經過8週訓練後，全身振動合併輕阻蹲跳組的運動表現有所提昇，包括力量之產生速率（進步量為37.4%-52.8%）和垂直跳高度（前測：70.96±4.26cm，後測：76.99±6.54cm），神經活化程度亦有增加，包括標準化肌電圖訊號之產生速率和標準化均單位伏特量，脊髓上運動神經元之總和興奮性也有上升（標準化V波，前測：0.23±0.08，後測：0.36±0.18），（p<0.0083），接受全身振動訓練之運動員，經過8週訓練後並不能讓脊髓或脊髓上運動神經元之總和興奮性、神經活化程度或運動能力表現有顯著改變，（p>0.0083），而在平地上進行輕阻蹲跳訓練之運動員，運動表現之提昇只出現在晚期（0-200ms）的力量之產生速率，（p<0.0083），在其它參數的表現上則無明顯改變，（p>0.0083），除此以外，本研究結果並沒有發現組別間經過訓練後的差異，（p>0.0167）。結論：經過8週全身振動協同輕阻蹲跳訓練後，可以增加運動員之跳躍能力和小腿後肌的力量之產生速率，這些改變可能來自於全身振動引起的張力性振動反射和蹲跳引起的牽張反射之效果，使脊髓上運動神經元之總和興奮性提高，以及神經活化程度的增加所引致的結果。

Background: Muscle force, explosive strength and vertical jump height are important parameters determining the performances of athletes. Traditionally, high intensity resistance training, explosive strength training and plyometric training are used to improve athletes’ performance. Recently, the whole body vibration training is recommended to increase muscle forces and explosive strength, because vibrating platforms can provide a high gravitational acceleration to enhance the sensory input to spinal reflexes, thus, increases muscle activation. Though the training effects have been discussed, the mechanisms of the neuromuscular adaptations in the traditional whole body vibration training have not yet been fully investigated. Training effects of combine training in addition to traditional whole body vibration training are neither discussed in this circumstance. Thus, the purpose of this study is to investigate the combining training effect of the whole body vibration training and light resistance squat jump exercise on the neural adaptations of triceps surae muscles. Design: Prospective study. Subjects: 24 Healthy male subjects with regular training or competition at least 6 hours per week were eligible to this study. Methods: H-reflex, V-wave, triceps surae electromyographic activities and rate of force development were measured at pre-test and post-test (8-week training). Subjects received 8-week- 3 times/week, training programs including light resistance squat jump (combine training) on whole body vibration platform, static squat (traditional training) on the whole body vibration platform or light resistance squat jump on the ground. Data analysis: Data was analyzed by using SPSS 13.0 software (SPSS Inc., Chicago, IL). Two-way ANOVA, Kruskal-Wallis test and Pearson correlation were used for data analysis. Results: After 8-weeks training, the rate of force development (37.4%-52.8% increase, p<0.0083) and vertical jump height (pre-test: 70.96±4.26cm, post-test: 76.99±6.54cm, p<0.0083) in the combine training group increased significantly. In the mean while, there were significant increased in the normalized rate of EMG rise and mean average voltage. Normalized V wave was also increased after the 8-weeks combine training (p<0.0083). Besides the combine training group, subjects performed light resistance squat jump on the ground increased their rate of force development in the 0-200ms time interval significantly (p<0.0083). Conclusion: After 8-weeks whole body vibration combining light resistance squat jump exercise, there were increased rate of force development and vertical jump height performance. Those increases might benefit from the combining effect of tonic vibration reflex and stretch reflex, leading to the increase of supraspinal motor-neurons activation and neural activation level.