Choose an appropriate weight matching your fitness and coordination level. Step under the bar and place the back of your shoulders across it, while you set the bar on a rack to just below shoulder level. Grab the barbell with a wide grip; palms facing forward. Hold the barbell leaning against the back of your shoulders and step away from the rack to make a full-range motion while positioning your legs using a shoulder-width medium stance with toes rotating up to 30 degrees.
Straighten your torso. Your pelvis is in a neutral position.
Begin to slowly lower the bar by bending your knees as you maintain a straight posture and breathe in. Your knees are following the rotation of your toes. Avoid excessive bending forward. Continue down until the angle between the upper leg and the calves becomes slightly less than 90 degrees. Breathing out, go back up the same way all the way to starting position. Repeat the motion as required without changing technique.
Keep your torso muscles upright and your pelvis in a neutral position.
Keep your knees pointing in the same direction as your toes all the way through and avoid oscillation while overcoming resistance. The front of the knees, head and torso should make an imaginary straight line with your toes perpendicular to the front. Keep your heels on the floor at all times.
Start with lighter weight to master the technique well.
To learn the technique, you may put a bench behind you and sit and rise from it. As your motion gets more fluent and your technique improves, you may lower your bench.
Barbell squat is arguably the most complex exercise in terms of muscles involved. The whole lower part of the body gets involved and so do the muscles around the waist (body core).
The main targeted muscles are quadriceps and glutes. These are both very large and very strong muscles and it is therefore necessary to use relatively heavy weights for the squat to be effective.
However, by placing the barbell on your shoulders you can potentially injure your upper back, lower back and shoulder joints. Therefore, only fit and healthy individuals should attempt heavy barbell squats.
The feet should be positioned shoulder-wide, and should be pointing outwards in an angle of about 30 degrees.
Make sure your knees are not in front of your toes. This is not easy: a good training method is to squat facing the wall, with your toes touching it.
Never lower you head. You could get dizzy and fall down with tragic consequences. Also, lowering the head will put the spinal cord in wrong position. The back must be straight during the whole exercise.
Lower your torso until your hips are slightly below the level of your knees. That’s also called “hitting the parallel”. The whole movement must be slow and fully controlled.
For better safety barbell squats can be done inside the rack cage.
The squat technique can be somewhat altered depending on where you want to increase or decrease the torque. It means that some alterations put more torque (and stress) on the knees and less on the lower back and vice versa. However, such experimenting should be done only under the supervision of experienced coach.