Having done squats now for a while, there are a few things that can throw off your balance in no order of precedence:
- Lack of flexibility
- Looking up or down
- Bad position in the hole (knees to far forward)
The number one mistake that I and many other people new to squats make is to look up. We're either looking in the mirror to evaluate our form or we are looking at our waist directly. Either way the head is not in an anatomically neutral position. It's amazing how a small adjustment like that can fix balance problems or back position problems.
To deal with flexibility, there are a few stretches that help out, and I recommend doing them before you start your session:
- Lunge stretches. Improves hip-flexor mobility and calf/ankle mobility. Both feet should be flat on the floor and you should keep your body vertical as you push your hip forward.
- Body weight squats. Hold your position at the bottom and push your knees out with your elbows. The crease of your hips should be below the top of your patella, and your balance should be in the middle of your foot. Hold it for about 10 seconds and do it at least twice. Memorize the way your body feels in this position, it's what you are trying to do when you have the weight on your back.
To deal with balance, there are a couple of variations with the squats to help you learn your body position:
- Blocks in front of your knees. The blocks should be tall enough so that your knee can touch it, and placed about 1-2 inches in front of your toes. When you squat touch the block with your knees but don't knock it over.
- Block under your butt. The block should be low enough so that the crease of your hips is below your patella, and positioned so that when your knees are at the right position you will touch the block with your butt, but not sit on it.
These variations help you to learn proper body position and get a better kinesthetic sense of yourself during the exercise. Remember with squats you are lowering your hips, not your back. If your hips aren't getting low enough it will throw off your balance as well (pushing your balance on your toes). The bar should always be over mid foot, as should your weight.