Baratta R, Solomonow M, Zhou B H, Letson D, Chuinard R, D'Ambrosia R
Department of Orthopaedic Surgery, Louisiana State University Medical Center, New Orleans.
Am J Sports Med. 1988 Mar-Apr;16(2):113-22. doi: 10.1177/036354658801600205.
The objective of this study was to quantify the coactivation patterns of the knee flexor and extensor muscles as part of continued efforts to identify the role of the antagonist muscles in maintaining joint stability. The simultaneous EMG from the flexor and extensor muscles of the knee were recorded during maximal effort, slow isokinetic contractions (15 deg/sec) on the plane parallel to the ground to eliminate the effect of gravity. The processed EMG from the antagonist muscle was normalized with respect to its EMG as agonist at maximal effort for each joint angle. The plots of normalized antagonist EMG versus joint angle for each muscle group were shown to relate inversely to their moment arm variations over the joint range of motion. Additional calculations demonstrated that the antagonist exerts nearly constant opposing torque throughout joint range of motion. Comparison of data recorded from normal healthy subjects with that of high performance athletes with hypertrophied quadriceps demonstrated strong inhibitory effects on the hamstrings coactivations. Athletes who routinely exercise their hamstrings, however, had a coactivation response similar to that of normal subjects. We concluded that coactivation of the antagonist is necessary to aid the ligaments in maintaining joint stability, equalizing the articular surface pressure distribution, and regulating the joint's mechanical impedance. The reduced coactivation pattern of the unexercised antagonist to a hypertrophied muscle increases the risk of ligamentous damage, as well as demonstrates the adaptive properties of the antagonist muscle in response to exercise. It was also concluded that reduced risk of knee injuries in high performance athletes with muscular imbalance could result from complementary resistive exercise of the antagonist muscle.
本研究的目的是量化膝关节屈肌和伸肌的共同激活模式，这是持续努力确定拮抗肌在维持关节稳定性中作用的一部分。在与地面平行的平面上进行最大努力、慢速等速收缩（15度/秒）时，记录膝关节屈肌和伸肌的同步肌电图，以消除重力的影响。将拮抗肌处理后的肌电图相对于其在每个关节角度最大努力时作为主动肌的肌电图进行归一化。结果显示，每个肌肉群归一化拮抗肌肌电图与关节角度的关系图与其在关节活动范围内的力臂变化呈反比。进一步的计算表明，拮抗肌在整个关节活动范围内施加几乎恒定的反向扭矩。将正常健康受试者与股四头肌肥大的高性能运动员记录的数据进行比较，结果表明对腘绳肌的共同激活有强烈的抑制作用。然而，经常锻炼腘绳肌的运动员的共同激活反应与正常受试者相似。我们得出结论，拮抗肌的共同激活对于帮助韧带维持关节稳定性、平衡关节表面压力分布以及调节关节的机械阻抗是必要的。未锻炼的拮抗肌对肥大肌肉的共同激活模式降低会增加韧带损伤的风险，同时也证明了拮抗肌对运动的适应性。研究还得出结论，肌肉失衡的高性能运动员膝关节受伤风险降低可能是由于拮抗肌的补充性抗阻运动。
