Seated Bent-over One-arm Dumbbell Triceps Extension

Sit on a bench, feet flat on the ground, and lean forward from the waist. Hold a dumbbell in one hand with your arm bent at 90 degrees. Without moving your upper arm, extend your forearm backwards until your entire arm is fully extended. Squeeze your tricep at the top of the movement and then slowly lower the dumbbell back to the starting position. Repeat for desired reps, then switch arms.