Sometimes I get a little impatient with training and I'm looking for something a bit more aerobic (I feel the opposite when I'm tired). Tonight, I was too impatient to do squats so I did lunges. I forgot how much those bitches burn. How often do you do lunges? Do you go back and forth between lunges and squats or do you do them both in one session? What benefits does one bring that the other doesn't?