Q: I don't seem to getting the results I expected from squats. Any ideas of where the problem is?
A: Squats are the most technique-governed exercise ever invented. Performed properly, they produce the greatest and most complete gains possible in leg size, muscularity and strength. But if you perform them improperly, you won't see gains in any of those areas. What's more, you'll probably injure yourself.
I'd bet that your problem is your hips. Squats are a compound movement, which means they involve the coordination of many different bodyparts, and your hips are the key to it all. If they are not free to rotate and pivot as necessary, nothing else in your body will work as it should. Your back won't be able to assume its strongest angle. Your abdominals and shoulders won't be able to provide support.
Your thigh and calf muscles won't be able to push with maximum power. And you won't be able to breathe efficiently, because you're bent over in a manner that prevents your chest from expanding fully.
You want more? I'll continue. Your knees will be taking most of the stress, the shear plane of the bar will cut right through the weakest part of your lower back, you might snap your Achilles tendons, and you'll promote arthritis in your hips. And that's just for starters.
The next time you're in the gym, observe the form most people use when squatting, then compare yours to theirs. Most likely, their backs and hips will be locked in position so tight that no joint is discernible between the two. Their backs will be a concave arch (slightly swaybacked), and their hips will jut out behind them, causing their upper bodies to lean forward.
This, instead, is what you should be doing: Your hips should swivel forward, under your upper body, to place the center of gravity and maximum support in your body's vertical axis. Keep your upper body comfortably upright. Your back should not be straining to hold the barbell. As you squat, allow your upper body to tilt as necessary--only enough to maintain balance, but not so much that it cantilevers in front of you, as if it's a support beam for the barbell. Before, when you were sticking your hips out behind you and leaning forward, you were restricted to partial squats and had no more range of motion than a beast of burden. Now, with your hips rotating and pivoting freely, you can squat all the way down to your calves, and this complete extension and contraction of your thighs is the only way to maximize their size and strength. From now on, when you think of squats, think "hip squats," and you'll find yourself exploring a vast new frontier of leg growth.