To perform barbell rows grip the barbell a little wider than shoulder width apart. Take the bar of the rack and bend forward with your back almost parrallel to the floor. Do not round your lower back - that is a sure way to injure it. Pull the barbell up with force to the bottom of your ribcage and lower the bar down slowly controlling the weight.

 

Keep your elbows close to your body throughout the entire movement and make sure to get a good squeeze at the top of the movement. Repeat the process.