Konrad Peter, Schmitz Klaus, Denner Achim
University of Dortmund, Dortmund, Germany.
J Athl Train. 2001 Jun;36(2):109-118.
To evaluate the neuromuscular activation profiles of trunk muscles in commonly used gymnastic strength exercises with a polymyographic set-up and to describe the training effects of each exercise. DESIGN AND SETTING: Subjects performed 9 repetitions of each of 12 gymnastic exercises. Variations of 5 trunk flexions, 5 extensions, and 2 lateral-flexion movements were performed under standardized test conditions. SUBJECTS: Ten healthy subjects (men and women) who were familiar with the exercises participated in the study. MEASUREMENTS: We recorded surface electromyograms (EMGs) from the rectus abdominis, external oblique, rectus femoris, middle trapezius, erector spinae at T12 and L3, gluteus maximus, and semitendinosus and semimembranosus muscles. Recording of each repetition cycle was triggered by a flexible electronic goniometer attached to the trunk. The raw EMG signals were rectified, smoothed, amplitude normalized to maximal voluntary contraction (MVC), and averaged for the last 8 repetitions. RESULTS: Pure spine-flexion exercises, such as a curl-up, produced sufficient and isolated activation (greater than 50% MVC) of the abdominal muscles. When flexion of the spine was combined with hip flexion (sit-up), the peak activation was increased. Lateral-flexion tasks targeted primarily the external oblique muscle, which demonstrated high activity in side-lying flexion tasks. Back- and hip-extension exercises, such as bridging and diagonal hip and shoulder extension, produced only moderate mean activities (less than 35% MVC) in the trunk-extensor muscles. Trunk-extension exercises with combined hip extension increased the EMG activity to 50% MVC but only at the end of the extension. CONCLUSIONS: Individual responses to each exercise varied markedly, which complicated the classification of exercise effects. However, within the limitations of the study, we found that the chosen abdominal exercises provided an effective training stimulus for the trunk-flexor muscles, whereas in the back- and hip-extension exercises, the neuromuscular activation tended to be too low or unspecific to qualify as muscle-specific training.
使用多肌电图装置评估常用体操力量练习中躯干肌肉的神经肌肉激活情况，并描述每种练习的训练效果。设计与环境：受试者对12种体操练习各进行9次重复。在标准化测试条件下进行5种躯干屈曲、5种伸展和2种侧屈动作的变体练习。受试者：10名熟悉这些练习的健康受试者（男女皆有）参与了该研究。测量：我们记录了腹直肌、腹外斜肌、股直肌、斜方肌中部、T12和L3水平的竖脊肌、臀大肌以及半腱肌和半膜肌的表面肌电图（EMG）。每个重复周期的记录由连接到躯干的柔性电子测角仪触发。原始EMG信号经过整流、平滑处理，将幅度归一化至最大自主收缩（MVC），并对最后8次重复进行平均。结果：单纯的脊柱屈曲练习，如仰卧起坐，能使腹部肌肉产生充分且孤立的激活（大于50%MVC）。当脊柱屈曲与髋关节屈曲相结合（仰卧起坐）时，峰值激活增加。侧屈任务主要针对腹外斜肌，该肌肉在侧卧屈曲任务中表现出高活性。背部和髋关节伸展练习，如臀桥和对角髋部与肩部伸展，在躯干伸肌中仅产生中等程度的平均活动（小于35%MVC）。结合髋关节伸展的躯干伸展练习可将EMG活动增加至50%MVC，但仅在伸展末期。结论：个体对每种练习的反应差异显著，这使得练习效果的分类变得复杂。然而，在该研究的局限性范围内，我们发现所选的腹部练习为躯干屈肌提供了有效的训练刺激，而在背部和髋关节伸展练习中，神经肌肉激活往往过低或不具特异性，无法作为特定肌肉的训练。
