Barbell Squats

Position your body in the squat rack so that the barbell rests behind your head on your shoulders and trapezius, not on your neck. Have a little bend in your knees, and take a comfortably wide grip on the bar.
 
Straighten your legs to lift the bar and then take one step backward.
 
Stand with your feet about shoulder width apart with your toes pointing forward at their natural angle.
 
Maintain the natural curve of your spine by tensing your abdominal and lower back muscles. Keep your head up, looking forward, throughout the exercise.
 
Squat down until your thighs are slightly below parallel to the floor, being sure to keep your torso fixed in the most erect position possible throughout the movement and your knees moving out in the same direction as your feet.
 
Reverse the movement and return to the starting position.
 
The entire motion should be done in a smooth, controlled manner that lasts about 4 seconds, with the downward movement no faster than the upward.
 
Do not bounce at the bottom of the movement and never lock your knees at the top.