Patikas D A, Bassa H, Kotzamanidis C
Department of Orthopaedic Surgery, University Orthopaedic Clinic of Heidelberg, Germany.
Int J Sports Med. 2006 Feb;27(2):124-30. doi: 10.1055/s-2005-837490.
The purpose of the study was to evaluate the soleus H-reflex amplitude during and after a low-intensity isometric contraction. Twelve healthy, untrained subjects performed a 10-minute isometric plantar flexion at 20% of their maximum voluntary contraction torque output. The electromyogram, H-reflex, and maximum M-wave (Mmax) of the soleus muscle was recorded during and 10 minutes after the end of the contraction. The results indicated that the H-reflex increased significantly (mean +/- SEM: 44.7 +/- 16.6%, p < 0.05), but when the fatigue protocol was over, the H-reflex was depressed for the first 3 minutes, relative to the H-reflex that was recorded before fatigue, when the muscle was relaxed. The Mmax did not change significantly during the whole experiment. Furthermore, the stimulation frequency (0.1 vs. 0.3 Hz) did not have any significant effect on the H-reflex modulation. The results of the current study suggest that the reflex excitability is increased as fatigue develops, whereas this increase turns to depression for the first minutes of the recovery phase. The functional significance of these changes and the neural mechanisms which might be responsible are discussed.
本研究的目的是评估在低强度等长收缩期间及之后比目鱼肌H反射的幅度。12名健康的未经训练的受试者以其最大自主收缩扭矩输出的20%进行了10分钟的等长跖屈。在收缩期间及收缩结束后10分钟记录比目鱼肌的肌电图、H反射和最大M波（Mmax）。结果表明，H反射显著增加（平均值±标准误：44.7±16.6%，p<0.05），但当疲劳方案结束时，与肌肉放松时疲劳前记录的H反射相比，H反射在最初3分钟内降低。在整个实验过程中，Mmax没有显著变化。此外，刺激频率（0.1Hz对0.3Hz）对H反射调制没有任何显著影响。当前研究的结果表明，随着疲劳的发展，反射兴奋性增加，而在恢复阶段的最初几分钟，这种增加转变为抑制。讨论了这些变化的功能意义以及可能的神经机制。
