This involves the quads, hamstrings, all of the back and traps and arms and is the most complete exercise.

Feet shoulder width apart, width of hands just outside your legs. YOu can either use an overhand grip or and alternate one where one hand is over and the other is under (this stops the bar twisting out of your hands as they oppose each other).

As every one always says when you pick something up, bend your knees!. Bend them so your thighs are almost parallel with the floor. THe bar will be right in front of your shins. Take the strain and keep everything tight then keeping your back straight, first push through the floor using your legs. As the bar rises your back comes into it and you straighten out until your body is vertical. Don't drop the weight though, control it on the way down too.

Repeat until you pass out