There was a bodybuilder back in the early 90's named JJ Marsh who had enormous thighs which I admired. He said in a magazine interview that his thighs started to grow like weeds once he changed his squatting routine from one session per week to three times a week. Well, being the sucker I was I tried just that. I began heavy squats 3 times per week and I continuted this for about a year. Sure enough, my legs exploaded with growth. Went from 26" to 29.5 in just under a year and although I only put on 3.5 inches on each thigh, the vascularity and definition is night and day. I highly recommend 3x/weekly squats if you have the stomach for it. It's not easy but the results speak for themselves.