Hope some of these muscle stimulation articles are making sense and helping you to better understand how we need FES units to do specific tasks to aid in the rehab. process.
Waveform is nothing but the description that is used to illustrate what electricity, leaving the unit, looks like. It is usually referred to as either square or sine wave.
The top wave is a sine wave and the second one down is a square wave.
As you can see with the square wave you have the FES unit off when the line is flat, then a sudden 90 degree vertical turn represents the unit has come on and it goes to a set intensity or amplitude and then holds that level until the unit stops transmitting and you see the rapid vertical descension to the base line.
Obviously why is this important, the wave form?
Most muscle nerves require a certain intensity and holding that intensity ( width) for some time period before you can make a muscle move. As a general rule the time period ( width) for larger muscles is 350 microseconds ( millionths of a second ). That number is variable according to the patient but some muscle stimulators do not have 350 when the electricity leaves the unit, forgetting the skin offers resistance and lowers the actual time and decays the wave form. This is especially relevant when one is trying to stimulate larger muscles such as the quads. The Infrex Plus tens mode actually has a 400 microsecond pulse width but again tens is for pain, possibly muscle pain, not for rehabilitation unless pain is hampering the process. If so then the pain must be overcome before the rehab. process can be successful.
When one chooses a FES unit it is very important to have a unit that can transmit TO THE NERVE enough energy. On large muscles the units that use only a 9 volt battery do not have sufficient energy to gain acceptable treatment parameters.
Hope this has helped some.