Tetanize

Thus, on tetanizing an only slightly irritable nerve, applied to the deriving cushions by its longitudinal and transverse sections very near to the exciting electrodes, with the alternating currents of the Inversor arranged so that its closing value in the unit of time is brought as near as possible to unity, frequently we get only a trace of negative variation, or none at all, or even a positive deflection; but, repeating the experiment several times, we always get a feeble negative variation.

Source: wiktionary

There is, in short, little doubt that the constituent of mammalian muscle which liberates carbon dioxide on prolonged boiling, is the same as that which is decomposed in tetanus and rigor; for if muscles are tetanized or made rigid, while at the same time opportunity is offered for th escape of the carbon dioxide which is known to be generated in those processes, the yield of dioxide on subsequent boiling is reduced to a mean of 20 or 30 vols. p. c. instead of 100.

Source: wiktionary

This tetanizing effect on muscles is most pronounced in frequencies from 15-150 cycles per second.

Source: wiktionary