The single-arm row tones the largest muscle of your back, which can minimize the dreaded bra-strap bulge. It works the biceps and the shoulders, too, and so improves your posture by counteracting muscle imbalances created by driving, daily computer use, and other activities, says Joan Pagano, the author of Strength Training Exercises for Women, who provided this routine to Real Simple. "And it can improve your performance in tennis, golf, and other sports," she adds.
Photograph by Henry Leutwyler, Illustration by Remie Geoffroi
Want to make it harder? To advance this move, use a heavier dumbbell and a weight bench. Keeping your back flat, put your right knee and right hand on the bench and your left foot on the floor. Without twisting your torso, do 10 reps with your left arm, then switch sides.