Isokinetic Closed Kinetic Chain Exercise using Electric Muscle Stimulation

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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.