Here’s a great reason to throw in an extra half rep during your next reverse fly: It can spur muscle growth in the back of your shoulders, says Men’s Health Fitness Director BJ Gaddour.

The technique increases muscle tension in your rear delts by overloading the hardest portion—the top—of the movement. It’s also the part of the exercise where the muscles in the back of your shoulders are most activated, Gaddour explains.

Do sets of 6 to 8 reps with a heavier load, or sets of 10 to 15 reps with a lighter load. You can use a challenging overhand grip, which zeroes in on your rear delts. You can also use a neutral grip to target your rear and lateral delts. Another option: Switch between an overhand and neutral grip.