The barbell bent-over row is a compound exercise (one that moves multiple joints) that targets the latissimus dorsi, teres major, middle trapezius, and rhomboids to work your middle back.
Position your feet shoulder-width apart. Bend over so your back and torso are not quite parallel with the floor. Hold the barbell with an overhand grip and with hands slightly wider than shoulder width. Keep your knees slightly flexed. Hold the bar straight down, with arms fully extended. This is where you start every rep.
Pull the bar straight up to the lower part of your chest, elbows pointed out and up. As in your starting position, keep your torso rigid, your back flat, and your knees slightly bent. Slowly allow your elbows to extend back to your starting position. Keep your head up and back straight at all times, and do NOT swing or use momentum to lift the weight! Repeat for however many reps you are performing for the particular weight of your barbells and your specific goals.