Final answer:
NMES Russian current is characterized by a biphasic, symmetrical, and polyphasic waveform. It does not have a rectangular waveform, but features a medium frequency and burst modulation designed for effective muscle strengthening.
Step-by-step explanation:
The waveform used with NMES (Neuromuscular Electrical Stimulation) Russian current is biphasic, symmetrical, and polyphasic. This current is a type of electrical stimulation specifically designed for muscle strengthening. NMES Russian current features a medium frequency of 2500 Hz with a burst modulation that creates a pulsed waveform, where each burst has a 10 millisecond duration occurring at a rate of 50 bursts per second.
The rectangular description does not generally apply to Russian current characteristics. Instead, this term is more often associated with direct current waveforms used in other types of electrical stimulation therapies.