This exercise is best performed inside a squat rack for safety purposes. To begin, first place a flat bench or a box behind you. The flat bench is used to teach you to set your hips back and to hit depth.
Then, set the bar on a rack that best matches your height. Once the correct height is chosen and the bar is loaded, step under the bar and place the back of your shoulders (slightly below the neck) across it.
Hold on to the bar using both arms at each side and lift it off the rack by first pushing with your legs and at the same time straightening your torso.
Step away from the rack and position your legs using a shoulder width medium stance with the toes slightly pointed out. Keep your head up at all times as looking down will get you off balance and also maintain a straight back. This will be your starting position. (Note: For the purposes of this discussion we will use the medium stance described above which targets overall development; however you can choose any of the three stances discussed in the foot stances section).
Begin to slowly lower the bar by bending the knees and sitting your hips back as you maintain a straight posture with the head up. Continue down until you slightly touch the bench behind you. Inhale as you perform this portion of the movement. Tip: If you performed the exercise correctly, the front of the knees should make an imaginary straight line with the toes that is perpendicular to the front. If your knees are past that imaginary line (if they are past your toes) then you are placing undue stress on the knee and the exercise has been performed incorrectly.
Begin to raise the bar as you exhale by pushing the floor with the heel of your foot as you straighten the legs and extend the hips to go back to the starting position.
Repeat for the recommended amount of repetitions.
Caution: This is not an exercise to be taken lightly. If you have back issues, substitute it with the dumbbell squat variation or a leg press instead. If you have a healthy back, ensure perfect form and never slouch the back forward as this can cause back injury. Be cautious as well with the weight used; in case of doubt, use less weight rather than more. The squat is a very safe exercise but only if performed properly.
Variations: As previously mentioned, there are various stances that can be used depending on what you want to emphasize.
You can also place a small block under the heels to improve balance.
Dumbbells can be used as well for resistance by holding them to your sides. The use of wrist wraps is a necessity due to the amount of weights used. I find this an excellent variation when my lower back begins to act up after many weeks of regular barbell squats. (Note: For wide stance dumbbell squats you will have to hold the dumbbells in between your legs as opposed to both sides in order to be able to distance your legs sufficiently).
Another way to perform these is by using a smith machine though I do not recommend this. The reason for not performing regular squats on the smith machine is that since the machine allows you to execute the exercise while leaning versus the bar, hip flexor involvement is minimized taking the hamstring out of the exercise. While this does take pressure off the lower back, hamstring involvement is a requirement to stabilize the knee-cap. So, as a result, what is created is a situation where destructive forces place a huge stress on the ACL (anterior cruciate ligament; a primary ligament in the knee capsule whose job is to provide knee stability) by pushing the knee-cap forward. For this reason, I highly recommend against smith machine use for squats and if you still insist on doing so, make sure it is a sporadic use rather than frequent, and also be sure to control the amount of weight used.
Alternative Exercises For Barbell Squat To A Bench