The barbell row is an excellent exercise for building up your back muscles. More specifically, you'll work your mid- and upper-back muscles, like the lats, rhomboids, traps, and rear delts.

Hold a barbell in both hands, with your hands about shoulder-width apart. Use a supinated (underhand) grip, with your knuckles facing the floor.

Lie under a barbell or Smith machine and grab the bar with an underhand grip slightly wider than shoulder-width. Position your feet and torso so that you’re at a 45-degree angle with the ground.