Isokinetic Closed Kinetic Chain Exercise using Electric Muscle Stimulation

1.利用电肌肉刺激进行等速闭合运动链训练研制了一种新型等速闭合运动链测试仪。有了这台机器，受试者可以移动他们的腿在渐进的弧形运动。在测力臂末端安装特制的脚踏板和测力传感器，当电刺激器刺激股直肌时，输出信号向脚尖方向位移。电刺激器刺激股内侧肌和股外侧肌时，输出方向不变。当用电肌肉刺激器刺激腘绳肌时，输出在跟骨方向上移位。据推测，双关节肌肉有助于控制输出方向。另一方面，单关节肌肉对输出方向的控制没有贡献。2.电刺激通过p38 MAP激酶途径诱导PC12m3细胞突起生长我们建立了一个能在各种物理刺激下显示突起生长的神经细胞系PC12m3。当培养的PC12突变体（PC12m3）细胞暴露于电刺激，p38 MAP激酶的活性增加，神经突生长大大增强。p38 MAP激酶抑制剂BS 203580可抑制神经突起的生长。长时间电刺激PC12m3细胞引起细胞死亡，SB203580增强。此外，我们检测到激活环磷酸腺苷反应元件结合蛋白（CREB）的电刺激在PC 12 m3细胞。CREB是一种转录因子，是ERK的靶点。这些结果表明，电刺激诱导神经突起生长通过p38 MAP激酶和CREB途径在PC 12 m3细胞和p38 MAP激酶是负责神经元细胞的存活。

1.Isokinetic closed kinetic chain exercise using electric muscle stimulationA new isokinetic testing machine was developed for CKC exercises. With this machine, subjects can move their legs in gradual arc of motions. A custom made foot plate and load cell were attached to the tip of dynamometer arm. When rectus femoris muscle was stimulated by the electric muscle stimulator, the output was displaced in a tiptoe direction. When vastus medialis and vastus lateralis were stimulated by the electric muscle stimulator, the output direction did not change. When hamstring muscle was stimulated by the electric muscle stimulator, the output was displaced in a calx direction. It is speculated that bi-articular muscle contributes to control of an output direction. On the other hand, mono-articular muscle do not contribute to control of an output direction. It is speculated that mono-articular muscle contributes to an absolute value of output force.2.Electrical stimulation induces neurite outgrowth in PC12m3 cells via the p38 MAP kinase pathwayWe developed a neural cell line PC12m3 which show neurite outgrowth by various physical stimuli. When cultures of the PC12 mutant (PC12m3) cells were exposed to electrical stimulation, activity of p38 MAP kinase increased and neurite outgrowth was greatly enhanced. The neurite extension was inhibited by the p38 MAP kinase inhibitor BS203580. Longer electrical stimulation of PC12m3 cells provoked cell death, which was enhanced by SB203580. Furthermore, we detected activation of cyclic AMP responsive element binding protein (CREB) by electrical stimulation in PC12m3 cells. CREB is a transcription factor that is the target of ERK. These findings suggest that electrical stimulation induce neurite outgrowth through p38 MAP kinase and CREB pathways in PC12m3 cells and that p38 MAP kinase is responsible for the survival of neuronal cells.