Bent over Kickbacks are a great way to work your way to having amazing Triceps like Madonna.
For how to do it, read more
Grab a dumbbell (8-15 lbs depending on your level) with your right hand. Put your left knee and hand onto a flat bench. Your torso should be parallel (or almost parallel) to the floor. Keep your right arm tucked into your side at a 90 degree angle. Slowly extend your arm out and keep your elbow in. At full extension of the movement, your arm should be almost straight and behind you. Try to focus all of the tension on your triceps. Slowly lower the dumbbell back to the starting position to complete one. Do this 12 times. Repeat with your opposite arm to complete one set. Do 3 sets.
Fit's Tip: Don't swing your arms. If you are finding it hard to keep your elbow at your side, switch to a lower weight. Be mindful not to arch your back.