How to gain the back muscle's EMG research has suggested that hitting bent-over barbell rows will work the larger muscle groups of the upper and lower back equally, making this a great overall back builder.[2] Like the deadlift, this is another technical move that requires excellent form but rewards you with a ton of muscle. In your workout: Do bent-over rows toward the start of your back workout for heavy sets in lower rep ranges, about 6-8 or 8-10. You may also be better able to support your lower back—which may have taken plenty of punishment by now—when placing one hand on a bench. The Smith machine allows you to concentrate only on pulling as much weight as possible, since you don't have to worry about balancing it. Bend over about 45 degrees, staying close to the bar, and expect a little contribution from the hips and knees when you're pounding out the heavy sets. The bent-over barbell row has a significantly greater lumbar load than many other back exercises, so it...