The thighs, more commonly known in the Iron Game as quads (quadriceps) are the largest and most powerful muscle group in the entire body. It therefore goes without saying that they will also account for much of a persons overall strength and weight.
Building the thighs is simple enough, but it does require heavy weight and hard work.
Squats are certainly the best way to build the thighs. My personal favourite method of squatting isn’t the traditional way (bar behind neck), but instead, a front-squat on a smith machine with my feet a little forward. I find this to be more effective for my body type (long legs and short upper body) allowing me to hit my quads more effectively, and also helping me to avoid the dreaded ‘bubble-butt syndrome’ which tends to afflict us longer-limbed folk who dare to squat the conventional way.
I’ve also found old-school, free-weight hack squats to be pretty effective at building my lower thigh area, and machine hack squats to be very effective for this also.
Whatever you do, for building big strong thighs, squats are the best you can do, and anyone who tells you any different simply isn’t being truthful. While the results each person will get from different types of squat will vary, you should always include some variation of the squat into your program if you want well developed thighs. You simply have to find which works best for you.
Alternatively (preferably as well as) you can do several sets of heavy dead lifts, which work the legs somewhat before the lower back takes control of the load.
One final alternative – although it’ll never come close to the kind of development you can get from squatting or dead lifting, is to cycle in a very hard gear until your legs crap out. Believe me, if you have never trained your legs before, don’t be surprised if you put on some size by doing some intense cycling in a hard gear. In fact, if you are new to leg training, hard cycling is a pretty good primer for weight training.