“Does electric stimulation actually build muscle?”
“Unless I’m terribly confused, you shock your muscle and your muscle contracts means your body is still doing some work. But as I recall from discussing this with some physical therapists and athletic trainers and a couple exercise physiologist (I run in some weird circles, believe it or not) part of the problem is that it doesn’t push your myofibers to the level of performance, and there’s no increase in heart rate to accommodate the relative increase in need for oxygen and whatnot, which results in limited potential for gain. But, having gotten stim many times myself, I can tell you them make a sore muscle feel a hell of a lot better after 20 minutes or so. Oh, and a lot of athletes do use it, just not the way Bruce Lee did in the movie. More for use on sore muscles, less to make your core muscles look good.”