Dumbbell sculpting back lines:
Compared with barbells, using one or two dumbbells for bent-over rowing exercises (one-arm rowing is safer for the lower back) can make the back muscles grow more quick.
One-arm dumbbell rowing has always been a favorite back exercise for seven-time Mr. Olympia winners Lee and Haney.
Doing dumbbell flexion and arm raise exercises on a supine bench can not only exercise the serratus anterior muscle of the chest, but also develop the muscles on both sides of the back.