Ye X, Beck T W, Wages N P
Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA.
Biol Sport. 2015 Sep;32(3):199-205. doi: 10.5604/20831862.1150301. Epub 2015 Apr 24.
The purpose of this study was to examine the acute effects of maximal concentric vs. eccentric exercise on the isometric strength of the elbow flexor, as well as the biceps brachii muscle electromyographic (EMG) responses in resistance-trained (RT) vs. untrained (UT) men. Thirteen RT men (age: 24 ± 4 years; height: 180.2 ± 7.7 cm; body weight: 92.2 ± 16.9 kg) and twelve UT men (age: 23 ± 4 years; height: 179.2 ± 5.0 cm; body weight: 81.5 ± 8.6 kg) performed six sets of ten maximal concentric isokinetic (CON) or eccentric isokinetic (ECC) elbow flexion exercise in two separate visits. Before and after the exercise interventions, maximal voluntary contractions (MVCs) were performed for testing isometric strength. In addition, bipolar surface EMG signals were detected from the biceps brachii muscle during the strength testing. Both CON and ECC caused isometric strength to decrease, regardless of the training status. However, ECC caused greater isometric strength decline than CON did for the UT group (p = 0.006), but not for the RT group. Both EMG amplitude and mean frequency significantly decreased and increased, respectively, regardless of the training status and exercise intervention. Resistance-trained men are less susceptible to eccentric exercise-induced muscle damage, but this advantage is not likely linked to the chronic resistance training-induced neural adaptations.
本研究的目的是检验最大向心收缩与离心收缩运动对肘屈肌等长力量的急性影响，以及抗阻训练（RT）和未训练（UT）男性肱二头肌肌电图（EMG）反应。13名抗阻训练男性（年龄：24±4岁；身高：180.2±7.7厘米；体重：92.2±16.9千克）和12名未训练男性（年龄：23±4岁；身高：179.2±5.0厘米；体重：81.5±8.6千克）在两次单独的访视中进行了六组，每组十次的最大向心等速（CON）或离心等速（ECC）肘屈运动。在运动干预前后，进行最大自主收缩（MVC）以测试等长力量。此外，在力量测试期间从肱二头肌检测双极表面肌电信号。无论训练状态如何，CON和ECC均导致等长力量下降。然而，ECC导致未训练组的等长力量下降幅度大于CON组（p = 0.006），但抗阻训练组并非如此。无论训练状态和运动干预如何，肌电幅度和平均频率均分别显著降低和增加。抗阻训练的男性较不易受离心运动诱导的肌肉损伤影响，但这种优势不太可能与长期抗阻训练诱导的神经适应有关。
