another phase begins with the lower mA intensity
As per safety concerns, a 20 % decrease in stimulation intensity [mA] occurs with every phase being started. You cannot change this settings as otherwise it could lead to a moderate pain sensation if mA would not go down when another phase begins.
When one phase ends and another phase begins, the new phase has a new set of parameters: Hz, uS, timing, type of stimulation pattern. Your previous mA level selected to achive the desired effect: either pain relief, muscle contraction or relaxation, might not be adequate with the new settings of the following phase. Therefore, the mA descease to the safe level and the user shoul adjust the new phase to the new comfortable level for the new parameters.
Phase 1: Warm Up: 5 Hz 220 uS, continuous, you sen it to 40mA which prtovides strong tingling sensation for worm up or vascularization.
Phase 2: Work/rest with contracitons: 40 Hz 220 Us: if this treatment would start with the same level of intensity, this will be a high automatic increase of actual output. Therefeore we decrease it to the overall-safe level of 20% less.