Rather, about the group classes . Know what it is ? If not, I'll tell you ! Usually they are held in the spacious halls where along one (and maybe more) wall hanging mirror in which you can look while doing exercise. It is something like a helper who is saying by : " Straighten your back ," " Below squat ," " Do not correct the other way ! " Well , and the like . But we ran into a little forward . Before turning to the lessons you have to walk a ritual, if you want to go …