My university has it exclusively for athletics. I pulled my groin and was able to use it. Works amazing. After practices Id get it treated and did for a few weeks straight and no problems since.
Muscle stimulators won't build muscle. Theres no resistance, its like trying to get a bicep workout (to build muscle) by just flexing end tensing them for 30minutes (good workout but won't build muslce) at least thats what i think...