Beck Travis W, Ye Xin, Wages Nathan P
Biophysics Laboratory, University of Oklahoma, Department of Health and Exercise Science, Huston Huffman Center, Norman, Oklahoma.
J Strength Cond Res. 2016 Mar;30(3):703-9. doi: 10.1519/JSC.0000000000001137.
The purpose of this study was to compare the electromyographic (EMG) intensity patterns after unilateral concentric vs. eccentric exercise in the dominant (DOM) and nondominant (NONDOM) forearm flexors. Twenty-six men (mean ± SD: age, 24.0 ± 3.7 years) volunteered to perform a maximal isometric muscle action of the DOM and NONDOM forearm flexors before (PRE) and immediately after (POST) a series of maximal concentric isokinetic or maximal eccentric isokinetic muscle actions of the DOM forearm flexors. The concentric isokinetic and eccentric isokinetic muscle actions were performed on separate days that were randomly ordered. However, in both cases, the subjects performed 6 sets of 10 maximal muscle actions. A bipolar surface EMG signal was detected from the biceps brachii of the DOM and NONDOM limbs during the PRE and POST isometric muscle actions. The signals were then analyzed with a wavelet analysis, and the resulting intensity patterns were classified with a paired pattern classification procedure. The results indicated that the EMG intensity patterns could be correctly classified into their respective PRE vs. POST categories with an accuracy rate that was significantly better than random (20 of 26 patterns = 76.9% accuracy) but only for the DOM limb following the eccentric muscle actions. All other classifications were not significantly better than random. These findings indicated that eccentric exercise had a significant influence on the muscle activation pattern for the forearm flexors. It is possible that the muscle damage resulting from eccentric exercise affects muscle spindle or golgi tendon organ or both activity, thereby altering the muscle activation pattern.
本研究的目的是比较优势（DOM）和非优势（NONDOM）前臂屈肌在单侧向心运动与离心运动后的肌电图（EMG）强度模式。26名男性（平均±标准差：年龄，24.0±3.7岁）自愿在优势前臂屈肌进行一系列最大向心等速或最大离心等速肌肉动作之前（PRE）和之后立即（POST），对优势和非优势前臂屈肌进行最大等长肌肉动作。向心等速和离心等速肌肉动作在随机安排的不同日子进行。然而，在两种情况下，受试者均进行6组，每组10次最大肌肉动作。在等长肌肉动作的PRE和POST阶段，从优势和非优势肢体的肱二头肌检测双极表面肌电信号。然后用小波分析对信号进行分析，并用配对模式分类程序对所得强度模式进行分类。结果表明，肌电强度模式能够以显著高于随机水平的准确率（26种模式中的20种 = 76.9%准确率）正确分类到各自的PRE与POST类别，但仅适用于离心肌肉动作后的优势肢体。所有其他分类并不显著优于随机水平。这些发现表明，离心运动对前臂屈肌的肌肉激活模式有显著影响。离心运动导致的肌肉损伤可能会影响肌梭或高尔基腱器官或两者的活动，从而改变肌肉激活模式。
