go"The effect may vary, depending on what muscles are affected. If chest muscles are contracted by an external current, the normal contraction-relaxation cycle for breathing cannot occur. This can produce asphyxiation. A shock that produces muscle contractions often will cause sudden contractions at many location in the body. People who 'jump"from a ladder when shocked or"jump" away from a source of shock are often experiencing rapid involuntary muscle contraction.
Certain currents cause fibrillation, which is a disruption of the normal,cyclical contraction of heat muscle. Compared with other muscle tissue,heat muscle tissue has the unique ability to generate an electrical pulse.One location in the heart muscle dominates and starts the synchronous contraction process of heart muscle.An externally applied current can disrupt the synchronous pulse and can cause fibrillation.Then each local element of heart tissue generates its own current, which causes local contraction.During this random contraction of local tissue,the heart loses coordinated pumping action.
The current that is likely to cause fibrillation is called a probability current. For a 60 Hz current,the fibrillation threshold probability current I,for an arm-to-arm or arm-to-leg connection are given by Lee as