I used to think it wasn't, but after my last couple workouts, I may be changing my stance on the subject. You see I used to believe that extreme soreness can be avoided by streching, and therefore soreness is a result of lack of stretching and not a good measure of how intense your workout was. Perhaps I just used that to comfort myself since I wasn't getting very sore from my work outs previously. Well my past few visits to the gym have been real intense and I've learned some killer excercises that have resulted in nearly dead body parts the following day... and this is WITH stretching as part of my routine! So my question now is, is soreness an effective measure of progress and gains?