A trap bar is a barbell shaped like a rectangle (or sometimes a diamond). To use it, step inside the shape, then grip the bar with hands at your sides (not in front of you as with a standard barbell). On the deadlift, it allows your torso to remain more upright, which lessens the risk that your lower back will lose its arch—a common precursor to injuries.
True to its name, the bar brings more of your trapezius muscles into action, helping you build a bigger “yoke.” If you can’t squat due to injury, using the trap bar for deadlifts may also keep your thighs growing. While the classic deadlift targets mainly your glutes and hamstrings, the trap bar shifts your position to emphasize the quads. Some lifters feel using the trap bar also boosts the amount they can squat.
Be sure to grab the center of the handles. If you don’t balance the bar evenly in your hands, you won’t be able to lift heavy.