“Electrifying sensations” may appear as a “strange feeling, starting in the feet and radiating up to the head, like electricity”, and can be “horrible” or “quite pleasant”. “Thermic sensations” of heat, burning, or coldness may be “diffusely wave-like”, “ascending”, or “...
[16,51]. Participants and trainers that have to execute this training have to know that frequencies below 20 Hz can cause chest pain, problems to the head and the jaw, and a feeling of discomfort [52]. For muscle strength, the frequency suggested had to be higher than 20 Hz, the ...