Avela J, Santos P M, Kyröläinen H, Komi P V
Department of Biology of Physical Activity, University of Jyväskylä, Finland.
Aviat Space Environ Med. 1994 Apr;65(4):301-8.
The neuromuscular characteristics of the triceps surae muscle were investigated during the various types of stretch-shortening cycle (SSC) muscle loading. The analysis concentrated on the preactivation and the contact phases of SSC. Muscle loading was changed unconventionally by artificially changing the condition of the gravity in drop jumps. This was accomplished by using a special lifting block system where the gravity could be modified to control loading and unloading effects of the triceps surae muscle. The normal gravity condition showed an advantage over the other gravity drop jump conditions for the measured parameters. The same tendency could be seen in the activation characteristics of the investigated muscles in the preactivation and eccentric phases. Further, the preactivation EMG was related to the eccentric peak angular velocity of the ankle joint. The correlation coefficients were 0.37 (p < 0.05) and 0.48 (p < 0.01) for the gastrocnemius and the soleus muscles, respectively. All the results emphasized considerable adaptation of the neuromuscular system to the normal gravity condition. However, the overall control of landing may also depend on the vestibular and visual inputs, which might modify even the earlier learned central programs.
在各种类型的拉长-缩短周期（SSC）肌肉负荷过程中，对小腿三头肌的神经肌肉特性进行了研究。分析集中在SSC的预激活和接触阶段。通过人为改变跳深时的重力条件，非常规地改变肌肉负荷。这是通过使用一种特殊的升降块系统来实现的，在该系统中，可以改变重力以控制小腿三头肌的加载和卸载效果。对于所测量的参数，正常重力条件比其他重力跳深条件具有优势。在所研究肌肉的预激活和离心阶段的激活特性中也可以看到相同的趋势。此外，预激活肌电图与踝关节的离心峰值角速度相关。腓肠肌和比目鱼肌的相关系数分别为0.37（p<0.05）和0.48（p<0.01）。所有结果都强调了神经肌肉系统对正常重力条件的显著适应性。然而，着陆的整体控制也可能取决于前庭和视觉输入，这甚至可能改变早期学习的中枢程序。
