:The frequency gives the number of single
pulses per second, and is quoted in Hz
(Hertz).
The frequency determines which types of muscle fiber will react
preferred. Slow-reacting fibers react to low pulse frequencies of
up to 15 Hz, quick-reacting fibers on the other hand respond
from approx. 35 Hz upwards. At pulses of approx. 45-70 Hz, the
muscles are permanently tensed and become fatigued rapidly.
Higher pulse frequencies should therefore be preferred for rapid
and maximum power training.