Best Arm Exercises for Women: Overhead extension with dumbbells
A. Stand with feet hip-width apart and knees slightly bent, and hold a dumbbell in one hand.
B. Reach your arm overhead, holding the dumbbell vertically. Keep wrists straight. Bend your elbow, lowering the dumbbell behind your head. Keep upper arm close to your head and elbows pointing toward the ceiling.
C. Straighten your arms upward. Finish off the reps for that arm and then repeat reps on the other side for a full set of 8 to 12 reps each arm.